4d6931c380
The reset_rsvds_bits_mask() function can use the guest walker's root level number instead of using a separate 'level' variable. Signed-off-by: Davidlohr Bueso <dave@gnu.org> Signed-off-by: Avi Kivity <avi@redhat.com>
4027 lines
96 KiB
C
4027 lines
96 KiB
C
/*
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* Kernel-based Virtual Machine driver for Linux
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*
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* This module enables machines with Intel VT-x extensions to run virtual
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* machines without emulation or binary translation.
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*
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* MMU support
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*
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* Copyright (C) 2006 Qumranet, Inc.
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* Copyright 2010 Red Hat, Inc. and/or its affiliates.
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*
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* Authors:
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* Yaniv Kamay <yaniv@qumranet.com>
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* Avi Kivity <avi@qumranet.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#include "irq.h"
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#include "mmu.h"
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#include "x86.h"
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#include "kvm_cache_regs.h"
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#include <linux/kvm_host.h>
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#include <linux/types.h>
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <linux/module.h>
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#include <linux/swap.h>
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#include <linux/hugetlb.h>
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#include <linux/compiler.h>
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#include <linux/srcu.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <asm/page.h>
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#include <asm/cmpxchg.h>
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#include <asm/io.h>
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#include <asm/vmx.h>
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/*
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* When setting this variable to true it enables Two-Dimensional-Paging
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* where the hardware walks 2 page tables:
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* 1. the guest-virtual to guest-physical
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* 2. while doing 1. it walks guest-physical to host-physical
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* If the hardware supports that we don't need to do shadow paging.
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*/
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bool tdp_enabled = false;
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enum {
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AUDIT_PRE_PAGE_FAULT,
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AUDIT_POST_PAGE_FAULT,
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AUDIT_PRE_PTE_WRITE,
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AUDIT_POST_PTE_WRITE,
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AUDIT_PRE_SYNC,
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AUDIT_POST_SYNC
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};
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#undef MMU_DEBUG
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#ifdef MMU_DEBUG
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#define pgprintk(x...) do { if (dbg) printk(x); } while (0)
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#define rmap_printk(x...) do { if (dbg) printk(x); } while (0)
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#else
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#define pgprintk(x...) do { } while (0)
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#define rmap_printk(x...) do { } while (0)
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#endif
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#ifdef MMU_DEBUG
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static bool dbg = 0;
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module_param(dbg, bool, 0644);
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#endif
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#ifndef MMU_DEBUG
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#define ASSERT(x) do { } while (0)
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#else
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#define ASSERT(x) \
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if (!(x)) { \
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printk(KERN_WARNING "assertion failed %s:%d: %s\n", \
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__FILE__, __LINE__, #x); \
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}
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#endif
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#define PTE_PREFETCH_NUM 8
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#define PT_FIRST_AVAIL_BITS_SHIFT 9
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#define PT64_SECOND_AVAIL_BITS_SHIFT 52
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#define PT64_LEVEL_BITS 9
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#define PT64_LEVEL_SHIFT(level) \
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(PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
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#define PT64_INDEX(address, level)\
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(((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))
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#define PT32_LEVEL_BITS 10
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#define PT32_LEVEL_SHIFT(level) \
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(PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
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#define PT32_LVL_OFFSET_MASK(level) \
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(PT32_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
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* PT32_LEVEL_BITS))) - 1))
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#define PT32_INDEX(address, level)\
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(((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
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#define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
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#define PT64_DIR_BASE_ADDR_MASK \
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(PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
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#define PT64_LVL_ADDR_MASK(level) \
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(PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
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* PT64_LEVEL_BITS))) - 1))
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#define PT64_LVL_OFFSET_MASK(level) \
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(PT64_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
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* PT64_LEVEL_BITS))) - 1))
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#define PT32_BASE_ADDR_MASK PAGE_MASK
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#define PT32_DIR_BASE_ADDR_MASK \
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(PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
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#define PT32_LVL_ADDR_MASK(level) \
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(PAGE_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
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* PT32_LEVEL_BITS))) - 1))
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#define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
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| PT64_NX_MASK)
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#define PTE_LIST_EXT 4
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#define ACC_EXEC_MASK 1
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#define ACC_WRITE_MASK PT_WRITABLE_MASK
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#define ACC_USER_MASK PT_USER_MASK
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#define ACC_ALL (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK)
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#include <trace/events/kvm.h>
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#define CREATE_TRACE_POINTS
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#include "mmutrace.h"
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#define SPTE_HOST_WRITEABLE (1ULL << PT_FIRST_AVAIL_BITS_SHIFT)
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#define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
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struct pte_list_desc {
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u64 *sptes[PTE_LIST_EXT];
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struct pte_list_desc *more;
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};
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struct kvm_shadow_walk_iterator {
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u64 addr;
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hpa_t shadow_addr;
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u64 *sptep;
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int level;
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unsigned index;
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};
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#define for_each_shadow_entry(_vcpu, _addr, _walker) \
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for (shadow_walk_init(&(_walker), _vcpu, _addr); \
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shadow_walk_okay(&(_walker)); \
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shadow_walk_next(&(_walker)))
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#define for_each_shadow_entry_lockless(_vcpu, _addr, _walker, spte) \
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for (shadow_walk_init(&(_walker), _vcpu, _addr); \
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shadow_walk_okay(&(_walker)) && \
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({ spte = mmu_spte_get_lockless(_walker.sptep); 1; }); \
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__shadow_walk_next(&(_walker), spte))
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static struct kmem_cache *pte_list_desc_cache;
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static struct kmem_cache *mmu_page_header_cache;
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static struct percpu_counter kvm_total_used_mmu_pages;
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static u64 __read_mostly shadow_nx_mask;
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static u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */
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static u64 __read_mostly shadow_user_mask;
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static u64 __read_mostly shadow_accessed_mask;
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static u64 __read_mostly shadow_dirty_mask;
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static u64 __read_mostly shadow_mmio_mask;
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static void mmu_spte_set(u64 *sptep, u64 spte);
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void kvm_mmu_set_mmio_spte_mask(u64 mmio_mask)
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{
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shadow_mmio_mask = mmio_mask;
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}
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EXPORT_SYMBOL_GPL(kvm_mmu_set_mmio_spte_mask);
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static void mark_mmio_spte(u64 *sptep, u64 gfn, unsigned access)
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{
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access &= ACC_WRITE_MASK | ACC_USER_MASK;
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trace_mark_mmio_spte(sptep, gfn, access);
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mmu_spte_set(sptep, shadow_mmio_mask | access | gfn << PAGE_SHIFT);
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}
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static bool is_mmio_spte(u64 spte)
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{
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return (spte & shadow_mmio_mask) == shadow_mmio_mask;
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}
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static gfn_t get_mmio_spte_gfn(u64 spte)
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{
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return (spte & ~shadow_mmio_mask) >> PAGE_SHIFT;
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}
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static unsigned get_mmio_spte_access(u64 spte)
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{
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return (spte & ~shadow_mmio_mask) & ~PAGE_MASK;
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}
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static bool set_mmio_spte(u64 *sptep, gfn_t gfn, pfn_t pfn, unsigned access)
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{
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if (unlikely(is_noslot_pfn(pfn))) {
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mark_mmio_spte(sptep, gfn, access);
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return true;
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}
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return false;
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}
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static inline u64 rsvd_bits(int s, int e)
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{
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return ((1ULL << (e - s + 1)) - 1) << s;
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}
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void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
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u64 dirty_mask, u64 nx_mask, u64 x_mask)
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{
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shadow_user_mask = user_mask;
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shadow_accessed_mask = accessed_mask;
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shadow_dirty_mask = dirty_mask;
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shadow_nx_mask = nx_mask;
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shadow_x_mask = x_mask;
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}
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EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
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static int is_cpuid_PSE36(void)
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{
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return 1;
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}
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static int is_nx(struct kvm_vcpu *vcpu)
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{
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return vcpu->arch.efer & EFER_NX;
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}
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static int is_shadow_present_pte(u64 pte)
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{
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return pte & PT_PRESENT_MASK && !is_mmio_spte(pte);
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}
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static int is_large_pte(u64 pte)
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{
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return pte & PT_PAGE_SIZE_MASK;
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}
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static int is_dirty_gpte(unsigned long pte)
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{
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return pte & PT_DIRTY_MASK;
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}
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static int is_rmap_spte(u64 pte)
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{
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return is_shadow_present_pte(pte);
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}
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static int is_last_spte(u64 pte, int level)
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{
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if (level == PT_PAGE_TABLE_LEVEL)
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return 1;
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if (is_large_pte(pte))
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return 1;
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return 0;
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}
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static pfn_t spte_to_pfn(u64 pte)
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{
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return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
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}
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static gfn_t pse36_gfn_delta(u32 gpte)
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{
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int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;
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return (gpte & PT32_DIR_PSE36_MASK) << shift;
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}
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#ifdef CONFIG_X86_64
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static void __set_spte(u64 *sptep, u64 spte)
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{
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*sptep = spte;
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}
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static void __update_clear_spte_fast(u64 *sptep, u64 spte)
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{
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*sptep = spte;
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}
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static u64 __update_clear_spte_slow(u64 *sptep, u64 spte)
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{
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return xchg(sptep, spte);
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}
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static u64 __get_spte_lockless(u64 *sptep)
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{
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return ACCESS_ONCE(*sptep);
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}
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static bool __check_direct_spte_mmio_pf(u64 spte)
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{
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/* It is valid if the spte is zapped. */
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return spte == 0ull;
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}
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#else
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union split_spte {
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struct {
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u32 spte_low;
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u32 spte_high;
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};
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u64 spte;
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};
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static void count_spte_clear(u64 *sptep, u64 spte)
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{
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struct kvm_mmu_page *sp = page_header(__pa(sptep));
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if (is_shadow_present_pte(spte))
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return;
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/* Ensure the spte is completely set before we increase the count */
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smp_wmb();
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sp->clear_spte_count++;
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}
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static void __set_spte(u64 *sptep, u64 spte)
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{
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union split_spte *ssptep, sspte;
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ssptep = (union split_spte *)sptep;
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sspte = (union split_spte)spte;
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ssptep->spte_high = sspte.spte_high;
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/*
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* If we map the spte from nonpresent to present, We should store
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* the high bits firstly, then set present bit, so cpu can not
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* fetch this spte while we are setting the spte.
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*/
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smp_wmb();
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ssptep->spte_low = sspte.spte_low;
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}
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static void __update_clear_spte_fast(u64 *sptep, u64 spte)
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{
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union split_spte *ssptep, sspte;
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ssptep = (union split_spte *)sptep;
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sspte = (union split_spte)spte;
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ssptep->spte_low = sspte.spte_low;
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/*
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* If we map the spte from present to nonpresent, we should clear
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* present bit firstly to avoid vcpu fetch the old high bits.
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*/
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smp_wmb();
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ssptep->spte_high = sspte.spte_high;
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count_spte_clear(sptep, spte);
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}
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static u64 __update_clear_spte_slow(u64 *sptep, u64 spte)
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{
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union split_spte *ssptep, sspte, orig;
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ssptep = (union split_spte *)sptep;
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sspte = (union split_spte)spte;
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/* xchg acts as a barrier before the setting of the high bits */
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orig.spte_low = xchg(&ssptep->spte_low, sspte.spte_low);
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orig.spte_high = ssptep->spte_high;
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ssptep->spte_high = sspte.spte_high;
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count_spte_clear(sptep, spte);
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return orig.spte;
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}
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|
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/*
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* The idea using the light way get the spte on x86_32 guest is from
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* gup_get_pte(arch/x86/mm/gup.c).
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* The difference is we can not catch the spte tlb flush if we leave
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* guest mode, so we emulate it by increase clear_spte_count when spte
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* is cleared.
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*/
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static u64 __get_spte_lockless(u64 *sptep)
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{
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struct kvm_mmu_page *sp = page_header(__pa(sptep));
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union split_spte spte, *orig = (union split_spte *)sptep;
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int count;
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retry:
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count = sp->clear_spte_count;
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smp_rmb();
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spte.spte_low = orig->spte_low;
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smp_rmb();
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spte.spte_high = orig->spte_high;
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smp_rmb();
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if (unlikely(spte.spte_low != orig->spte_low ||
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count != sp->clear_spte_count))
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goto retry;
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|
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return spte.spte;
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}
|
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|
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static bool __check_direct_spte_mmio_pf(u64 spte)
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{
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union split_spte sspte = (union split_spte)spte;
|
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u32 high_mmio_mask = shadow_mmio_mask >> 32;
|
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|
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/* It is valid if the spte is zapped. */
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if (spte == 0ull)
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return true;
|
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|
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/* It is valid if the spte is being zapped. */
|
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if (sspte.spte_low == 0ull &&
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(sspte.spte_high & high_mmio_mask) == high_mmio_mask)
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return true;
|
|
|
|
return false;
|
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}
|
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#endif
|
|
|
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static bool spte_has_volatile_bits(u64 spte)
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{
|
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if (!shadow_accessed_mask)
|
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return false;
|
|
|
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if (!is_shadow_present_pte(spte))
|
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return false;
|
|
|
|
if ((spte & shadow_accessed_mask) &&
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(!is_writable_pte(spte) || (spte & shadow_dirty_mask)))
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return false;
|
|
|
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return true;
|
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}
|
|
|
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static bool spte_is_bit_cleared(u64 old_spte, u64 new_spte, u64 bit_mask)
|
|
{
|
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return (old_spte & bit_mask) && !(new_spte & bit_mask);
|
|
}
|
|
|
|
/* Rules for using mmu_spte_set:
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* Set the sptep from nonpresent to present.
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|
* Note: the sptep being assigned *must* be either not present
|
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* or in a state where the hardware will not attempt to update
|
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* the spte.
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|
*/
|
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static void mmu_spte_set(u64 *sptep, u64 new_spte)
|
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{
|
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WARN_ON(is_shadow_present_pte(*sptep));
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__set_spte(sptep, new_spte);
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}
|
|
|
|
/* Rules for using mmu_spte_update:
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* Update the state bits, it means the mapped pfn is not changged.
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*/
|
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static void mmu_spte_update(u64 *sptep, u64 new_spte)
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{
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u64 mask, old_spte = *sptep;
|
|
|
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WARN_ON(!is_rmap_spte(new_spte));
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|
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if (!is_shadow_present_pte(old_spte))
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return mmu_spte_set(sptep, new_spte);
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|
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new_spte |= old_spte & shadow_dirty_mask;
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|
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mask = shadow_accessed_mask;
|
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if (is_writable_pte(old_spte))
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mask |= shadow_dirty_mask;
|
|
|
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if (!spte_has_volatile_bits(old_spte) || (new_spte & mask) == mask)
|
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__update_clear_spte_fast(sptep, new_spte);
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else
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old_spte = __update_clear_spte_slow(sptep, new_spte);
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|
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if (!shadow_accessed_mask)
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return;
|
|
|
|
if (spte_is_bit_cleared(old_spte, new_spte, shadow_accessed_mask))
|
|
kvm_set_pfn_accessed(spte_to_pfn(old_spte));
|
|
if (spte_is_bit_cleared(old_spte, new_spte, shadow_dirty_mask))
|
|
kvm_set_pfn_dirty(spte_to_pfn(old_spte));
|
|
}
|
|
|
|
/*
|
|
* Rules for using mmu_spte_clear_track_bits:
|
|
* It sets the sptep from present to nonpresent, and track the
|
|
* state bits, it is used to clear the last level sptep.
|
|
*/
|
|
static int mmu_spte_clear_track_bits(u64 *sptep)
|
|
{
|
|
pfn_t pfn;
|
|
u64 old_spte = *sptep;
|
|
|
|
if (!spte_has_volatile_bits(old_spte))
|
|
__update_clear_spte_fast(sptep, 0ull);
|
|
else
|
|
old_spte = __update_clear_spte_slow(sptep, 0ull);
|
|
|
|
if (!is_rmap_spte(old_spte))
|
|
return 0;
|
|
|
|
pfn = spte_to_pfn(old_spte);
|
|
if (!shadow_accessed_mask || old_spte & shadow_accessed_mask)
|
|
kvm_set_pfn_accessed(pfn);
|
|
if (!shadow_dirty_mask || (old_spte & shadow_dirty_mask))
|
|
kvm_set_pfn_dirty(pfn);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Rules for using mmu_spte_clear_no_track:
|
|
* Directly clear spte without caring the state bits of sptep,
|
|
* it is used to set the upper level spte.
|
|
*/
|
|
static void mmu_spte_clear_no_track(u64 *sptep)
|
|
{
|
|
__update_clear_spte_fast(sptep, 0ull);
|
|
}
|
|
|
|
static u64 mmu_spte_get_lockless(u64 *sptep)
|
|
{
|
|
return __get_spte_lockless(sptep);
|
|
}
|
|
|
|
static void walk_shadow_page_lockless_begin(struct kvm_vcpu *vcpu)
|
|
{
|
|
rcu_read_lock();
|
|
atomic_inc(&vcpu->kvm->arch.reader_counter);
|
|
|
|
/* Increase the counter before walking shadow page table */
|
|
smp_mb__after_atomic_inc();
|
|
}
|
|
|
|
static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
|
|
{
|
|
/* Decrease the counter after walking shadow page table finished */
|
|
smp_mb__before_atomic_dec();
|
|
atomic_dec(&vcpu->kvm->arch.reader_counter);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
|
|
struct kmem_cache *base_cache, int min)
|
|
{
|
|
void *obj;
|
|
|
|
if (cache->nobjs >= min)
|
|
return 0;
|
|
while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
|
|
obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
|
|
if (!obj)
|
|
return -ENOMEM;
|
|
cache->objects[cache->nobjs++] = obj;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int mmu_memory_cache_free_objects(struct kvm_mmu_memory_cache *cache)
|
|
{
|
|
return cache->nobjs;
|
|
}
|
|
|
|
static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc,
|
|
struct kmem_cache *cache)
|
|
{
|
|
while (mc->nobjs)
|
|
kmem_cache_free(cache, mc->objects[--mc->nobjs]);
|
|
}
|
|
|
|
static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
|
|
int min)
|
|
{
|
|
void *page;
|
|
|
|
if (cache->nobjs >= min)
|
|
return 0;
|
|
while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
|
|
page = (void *)__get_free_page(GFP_KERNEL);
|
|
if (!page)
|
|
return -ENOMEM;
|
|
cache->objects[cache->nobjs++] = page;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
|
|
{
|
|
while (mc->nobjs)
|
|
free_page((unsigned long)mc->objects[--mc->nobjs]);
|
|
}
|
|
|
|
static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
|
|
{
|
|
int r;
|
|
|
|
r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
|
|
pte_list_desc_cache, 8 + PTE_PREFETCH_NUM);
|
|
if (r)
|
|
goto out;
|
|
r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
|
|
if (r)
|
|
goto out;
|
|
r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
|
|
mmu_page_header_cache, 4);
|
|
out:
|
|
return r;
|
|
}
|
|
|
|
static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
|
|
{
|
|
mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
|
|
pte_list_desc_cache);
|
|
mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
|
|
mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache,
|
|
mmu_page_header_cache);
|
|
}
|
|
|
|
static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
|
|
size_t size)
|
|
{
|
|
void *p;
|
|
|
|
BUG_ON(!mc->nobjs);
|
|
p = mc->objects[--mc->nobjs];
|
|
return p;
|
|
}
|
|
|
|
static struct pte_list_desc *mmu_alloc_pte_list_desc(struct kvm_vcpu *vcpu)
|
|
{
|
|
return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_list_desc_cache,
|
|
sizeof(struct pte_list_desc));
|
|
}
|
|
|
|
static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc)
|
|
{
|
|
kmem_cache_free(pte_list_desc_cache, pte_list_desc);
|
|
}
|
|
|
|
static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index)
|
|
{
|
|
if (!sp->role.direct)
|
|
return sp->gfns[index];
|
|
|
|
return sp->gfn + (index << ((sp->role.level - 1) * PT64_LEVEL_BITS));
|
|
}
|
|
|
|
static void kvm_mmu_page_set_gfn(struct kvm_mmu_page *sp, int index, gfn_t gfn)
|
|
{
|
|
if (sp->role.direct)
|
|
BUG_ON(gfn != kvm_mmu_page_get_gfn(sp, index));
|
|
else
|
|
sp->gfns[index] = gfn;
|
|
}
|
|
|
|
/*
|
|
* Return the pointer to the large page information for a given gfn,
|
|
* handling slots that are not large page aligned.
|
|
*/
|
|
static struct kvm_lpage_info *lpage_info_slot(gfn_t gfn,
|
|
struct kvm_memory_slot *slot,
|
|
int level)
|
|
{
|
|
unsigned long idx;
|
|
|
|
idx = gfn_to_index(gfn, slot->base_gfn, level);
|
|
return &slot->arch.lpage_info[level - 2][idx];
|
|
}
|
|
|
|
static void account_shadowed(struct kvm *kvm, gfn_t gfn)
|
|
{
|
|
struct kvm_memory_slot *slot;
|
|
struct kvm_lpage_info *linfo;
|
|
int i;
|
|
|
|
slot = gfn_to_memslot(kvm, gfn);
|
|
for (i = PT_DIRECTORY_LEVEL;
|
|
i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
|
|
linfo = lpage_info_slot(gfn, slot, i);
|
|
linfo->write_count += 1;
|
|
}
|
|
kvm->arch.indirect_shadow_pages++;
|
|
}
|
|
|
|
static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
|
|
{
|
|
struct kvm_memory_slot *slot;
|
|
struct kvm_lpage_info *linfo;
|
|
int i;
|
|
|
|
slot = gfn_to_memslot(kvm, gfn);
|
|
for (i = PT_DIRECTORY_LEVEL;
|
|
i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
|
|
linfo = lpage_info_slot(gfn, slot, i);
|
|
linfo->write_count -= 1;
|
|
WARN_ON(linfo->write_count < 0);
|
|
}
|
|
kvm->arch.indirect_shadow_pages--;
|
|
}
|
|
|
|
static int has_wrprotected_page(struct kvm *kvm,
|
|
gfn_t gfn,
|
|
int level)
|
|
{
|
|
struct kvm_memory_slot *slot;
|
|
struct kvm_lpage_info *linfo;
|
|
|
|
slot = gfn_to_memslot(kvm, gfn);
|
|
if (slot) {
|
|
linfo = lpage_info_slot(gfn, slot, level);
|
|
return linfo->write_count;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int host_mapping_level(struct kvm *kvm, gfn_t gfn)
|
|
{
|
|
unsigned long page_size;
|
|
int i, ret = 0;
|
|
|
|
page_size = kvm_host_page_size(kvm, gfn);
|
|
|
|
for (i = PT_PAGE_TABLE_LEVEL;
|
|
i < (PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES); ++i) {
|
|
if (page_size >= KVM_HPAGE_SIZE(i))
|
|
ret = i;
|
|
else
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static struct kvm_memory_slot *
|
|
gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t gfn,
|
|
bool no_dirty_log)
|
|
{
|
|
struct kvm_memory_slot *slot;
|
|
|
|
slot = gfn_to_memslot(vcpu->kvm, gfn);
|
|
if (!slot || slot->flags & KVM_MEMSLOT_INVALID ||
|
|
(no_dirty_log && slot->dirty_bitmap))
|
|
slot = NULL;
|
|
|
|
return slot;
|
|
}
|
|
|
|
static bool mapping_level_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t large_gfn)
|
|
{
|
|
return !gfn_to_memslot_dirty_bitmap(vcpu, large_gfn, true);
|
|
}
|
|
|
|
static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn)
|
|
{
|
|
int host_level, level, max_level;
|
|
|
|
host_level = host_mapping_level(vcpu->kvm, large_gfn);
|
|
|
|
if (host_level == PT_PAGE_TABLE_LEVEL)
|
|
return host_level;
|
|
|
|
max_level = kvm_x86_ops->get_lpage_level() < host_level ?
|
|
kvm_x86_ops->get_lpage_level() : host_level;
|
|
|
|
for (level = PT_DIRECTORY_LEVEL; level <= max_level; ++level)
|
|
if (has_wrprotected_page(vcpu->kvm, large_gfn, level))
|
|
break;
|
|
|
|
return level - 1;
|
|
}
|
|
|
|
/*
|
|
* Pte mapping structures:
|
|
*
|
|
* If pte_list bit zero is zero, then pte_list point to the spte.
|
|
*
|
|
* If pte_list bit zero is one, (then pte_list & ~1) points to a struct
|
|
* pte_list_desc containing more mappings.
|
|
*
|
|
* Returns the number of pte entries before the spte was added or zero if
|
|
* the spte was not added.
|
|
*
|
|
*/
|
|
static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte,
|
|
unsigned long *pte_list)
|
|
{
|
|
struct pte_list_desc *desc;
|
|
int i, count = 0;
|
|
|
|
if (!*pte_list) {
|
|
rmap_printk("pte_list_add: %p %llx 0->1\n", spte, *spte);
|
|
*pte_list = (unsigned long)spte;
|
|
} else if (!(*pte_list & 1)) {
|
|
rmap_printk("pte_list_add: %p %llx 1->many\n", spte, *spte);
|
|
desc = mmu_alloc_pte_list_desc(vcpu);
|
|
desc->sptes[0] = (u64 *)*pte_list;
|
|
desc->sptes[1] = spte;
|
|
*pte_list = (unsigned long)desc | 1;
|
|
++count;
|
|
} else {
|
|
rmap_printk("pte_list_add: %p %llx many->many\n", spte, *spte);
|
|
desc = (struct pte_list_desc *)(*pte_list & ~1ul);
|
|
while (desc->sptes[PTE_LIST_EXT-1] && desc->more) {
|
|
desc = desc->more;
|
|
count += PTE_LIST_EXT;
|
|
}
|
|
if (desc->sptes[PTE_LIST_EXT-1]) {
|
|
desc->more = mmu_alloc_pte_list_desc(vcpu);
|
|
desc = desc->more;
|
|
}
|
|
for (i = 0; desc->sptes[i]; ++i)
|
|
++count;
|
|
desc->sptes[i] = spte;
|
|
}
|
|
return count;
|
|
}
|
|
|
|
static u64 *pte_list_next(unsigned long *pte_list, u64 *spte)
|
|
{
|
|
struct pte_list_desc *desc;
|
|
u64 *prev_spte;
|
|
int i;
|
|
|
|
if (!*pte_list)
|
|
return NULL;
|
|
else if (!(*pte_list & 1)) {
|
|
if (!spte)
|
|
return (u64 *)*pte_list;
|
|
return NULL;
|
|
}
|
|
desc = (struct pte_list_desc *)(*pte_list & ~1ul);
|
|
prev_spte = NULL;
|
|
while (desc) {
|
|
for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i) {
|
|
if (prev_spte == spte)
|
|
return desc->sptes[i];
|
|
prev_spte = desc->sptes[i];
|
|
}
|
|
desc = desc->more;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static void
|
|
pte_list_desc_remove_entry(unsigned long *pte_list, struct pte_list_desc *desc,
|
|
int i, struct pte_list_desc *prev_desc)
|
|
{
|
|
int j;
|
|
|
|
for (j = PTE_LIST_EXT - 1; !desc->sptes[j] && j > i; --j)
|
|
;
|
|
desc->sptes[i] = desc->sptes[j];
|
|
desc->sptes[j] = NULL;
|
|
if (j != 0)
|
|
return;
|
|
if (!prev_desc && !desc->more)
|
|
*pte_list = (unsigned long)desc->sptes[0];
|
|
else
|
|
if (prev_desc)
|
|
prev_desc->more = desc->more;
|
|
else
|
|
*pte_list = (unsigned long)desc->more | 1;
|
|
mmu_free_pte_list_desc(desc);
|
|
}
|
|
|
|
static void pte_list_remove(u64 *spte, unsigned long *pte_list)
|
|
{
|
|
struct pte_list_desc *desc;
|
|
struct pte_list_desc *prev_desc;
|
|
int i;
|
|
|
|
if (!*pte_list) {
|
|
printk(KERN_ERR "pte_list_remove: %p 0->BUG\n", spte);
|
|
BUG();
|
|
} else if (!(*pte_list & 1)) {
|
|
rmap_printk("pte_list_remove: %p 1->0\n", spte);
|
|
if ((u64 *)*pte_list != spte) {
|
|
printk(KERN_ERR "pte_list_remove: %p 1->BUG\n", spte);
|
|
BUG();
|
|
}
|
|
*pte_list = 0;
|
|
} else {
|
|
rmap_printk("pte_list_remove: %p many->many\n", spte);
|
|
desc = (struct pte_list_desc *)(*pte_list & ~1ul);
|
|
prev_desc = NULL;
|
|
while (desc) {
|
|
for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i)
|
|
if (desc->sptes[i] == spte) {
|
|
pte_list_desc_remove_entry(pte_list,
|
|
desc, i,
|
|
prev_desc);
|
|
return;
|
|
}
|
|
prev_desc = desc;
|
|
desc = desc->more;
|
|
}
|
|
pr_err("pte_list_remove: %p many->many\n", spte);
|
|
BUG();
|
|
}
|
|
}
|
|
|
|
typedef void (*pte_list_walk_fn) (u64 *spte);
|
|
static void pte_list_walk(unsigned long *pte_list, pte_list_walk_fn fn)
|
|
{
|
|
struct pte_list_desc *desc;
|
|
int i;
|
|
|
|
if (!*pte_list)
|
|
return;
|
|
|
|
if (!(*pte_list & 1))
|
|
return fn((u64 *)*pte_list);
|
|
|
|
desc = (struct pte_list_desc *)(*pte_list & ~1ul);
|
|
while (desc) {
|
|
for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i)
|
|
fn(desc->sptes[i]);
|
|
desc = desc->more;
|
|
}
|
|
}
|
|
|
|
static unsigned long *__gfn_to_rmap(gfn_t gfn, int level,
|
|
struct kvm_memory_slot *slot)
|
|
{
|
|
struct kvm_lpage_info *linfo;
|
|
|
|
if (likely(level == PT_PAGE_TABLE_LEVEL))
|
|
return &slot->rmap[gfn - slot->base_gfn];
|
|
|
|
linfo = lpage_info_slot(gfn, slot, level);
|
|
return &linfo->rmap_pde;
|
|
}
|
|
|
|
/*
|
|
* Take gfn and return the reverse mapping to it.
|
|
*/
|
|
static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level)
|
|
{
|
|
struct kvm_memory_slot *slot;
|
|
|
|
slot = gfn_to_memslot(kvm, gfn);
|
|
return __gfn_to_rmap(gfn, level, slot);
|
|
}
|
|
|
|
static bool rmap_can_add(struct kvm_vcpu *vcpu)
|
|
{
|
|
struct kvm_mmu_memory_cache *cache;
|
|
|
|
cache = &vcpu->arch.mmu_pte_list_desc_cache;
|
|
return mmu_memory_cache_free_objects(cache);
|
|
}
|
|
|
|
static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
|
|
{
|
|
struct kvm_mmu_page *sp;
|
|
unsigned long *rmapp;
|
|
|
|
sp = page_header(__pa(spte));
|
|
kvm_mmu_page_set_gfn(sp, spte - sp->spt, gfn);
|
|
rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
|
|
return pte_list_add(vcpu, spte, rmapp);
|
|
}
|
|
|
|
static u64 *rmap_next(unsigned long *rmapp, u64 *spte)
|
|
{
|
|
return pte_list_next(rmapp, spte);
|
|
}
|
|
|
|
static void rmap_remove(struct kvm *kvm, u64 *spte)
|
|
{
|
|
struct kvm_mmu_page *sp;
|
|
gfn_t gfn;
|
|
unsigned long *rmapp;
|
|
|
|
sp = page_header(__pa(spte));
|
|
gfn = kvm_mmu_page_get_gfn(sp, spte - sp->spt);
|
|
rmapp = gfn_to_rmap(kvm, gfn, sp->role.level);
|
|
pte_list_remove(spte, rmapp);
|
|
}
|
|
|
|
static void drop_spte(struct kvm *kvm, u64 *sptep)
|
|
{
|
|
if (mmu_spte_clear_track_bits(sptep))
|
|
rmap_remove(kvm, sptep);
|
|
}
|
|
|
|
int kvm_mmu_rmap_write_protect(struct kvm *kvm, u64 gfn,
|
|
struct kvm_memory_slot *slot)
|
|
{
|
|
unsigned long *rmapp;
|
|
u64 *spte;
|
|
int i, write_protected = 0;
|
|
|
|
rmapp = __gfn_to_rmap(gfn, PT_PAGE_TABLE_LEVEL, slot);
|
|
spte = rmap_next(rmapp, NULL);
|
|
while (spte) {
|
|
BUG_ON(!(*spte & PT_PRESENT_MASK));
|
|
rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
|
|
if (is_writable_pte(*spte)) {
|
|
mmu_spte_update(spte, *spte & ~PT_WRITABLE_MASK);
|
|
write_protected = 1;
|
|
}
|
|
spte = rmap_next(rmapp, spte);
|
|
}
|
|
|
|
/* check for huge page mappings */
|
|
for (i = PT_DIRECTORY_LEVEL;
|
|
i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
|
|
rmapp = __gfn_to_rmap(gfn, i, slot);
|
|
spte = rmap_next(rmapp, NULL);
|
|
while (spte) {
|
|
BUG_ON(!(*spte & PT_PRESENT_MASK));
|
|
BUG_ON(!is_large_pte(*spte));
|
|
pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
|
|
if (is_writable_pte(*spte)) {
|
|
drop_spte(kvm, spte);
|
|
--kvm->stat.lpages;
|
|
spte = NULL;
|
|
write_protected = 1;
|
|
}
|
|
spte = rmap_next(rmapp, spte);
|
|
}
|
|
}
|
|
|
|
return write_protected;
|
|
}
|
|
|
|
static int rmap_write_protect(struct kvm *kvm, u64 gfn)
|
|
{
|
|
struct kvm_memory_slot *slot;
|
|
|
|
slot = gfn_to_memslot(kvm, gfn);
|
|
return kvm_mmu_rmap_write_protect(kvm, gfn, slot);
|
|
}
|
|
|
|
static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
|
|
unsigned long data)
|
|
{
|
|
u64 *spte;
|
|
int need_tlb_flush = 0;
|
|
|
|
while ((spte = rmap_next(rmapp, NULL))) {
|
|
BUG_ON(!(*spte & PT_PRESENT_MASK));
|
|
rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", spte, *spte);
|
|
drop_spte(kvm, spte);
|
|
need_tlb_flush = 1;
|
|
}
|
|
return need_tlb_flush;
|
|
}
|
|
|
|
static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,
|
|
unsigned long data)
|
|
{
|
|
int need_flush = 0;
|
|
u64 *spte, new_spte;
|
|
pte_t *ptep = (pte_t *)data;
|
|
pfn_t new_pfn;
|
|
|
|
WARN_ON(pte_huge(*ptep));
|
|
new_pfn = pte_pfn(*ptep);
|
|
spte = rmap_next(rmapp, NULL);
|
|
while (spte) {
|
|
BUG_ON(!is_shadow_present_pte(*spte));
|
|
rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", spte, *spte);
|
|
need_flush = 1;
|
|
if (pte_write(*ptep)) {
|
|
drop_spte(kvm, spte);
|
|
spte = rmap_next(rmapp, NULL);
|
|
} else {
|
|
new_spte = *spte &~ (PT64_BASE_ADDR_MASK);
|
|
new_spte |= (u64)new_pfn << PAGE_SHIFT;
|
|
|
|
new_spte &= ~PT_WRITABLE_MASK;
|
|
new_spte &= ~SPTE_HOST_WRITEABLE;
|
|
new_spte &= ~shadow_accessed_mask;
|
|
mmu_spte_clear_track_bits(spte);
|
|
mmu_spte_set(spte, new_spte);
|
|
spte = rmap_next(rmapp, spte);
|
|
}
|
|
}
|
|
if (need_flush)
|
|
kvm_flush_remote_tlbs(kvm);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
|
|
unsigned long data,
|
|
int (*handler)(struct kvm *kvm, unsigned long *rmapp,
|
|
unsigned long data))
|
|
{
|
|
int j;
|
|
int ret;
|
|
int retval = 0;
|
|
struct kvm_memslots *slots;
|
|
struct kvm_memory_slot *memslot;
|
|
|
|
slots = kvm_memslots(kvm);
|
|
|
|
kvm_for_each_memslot(memslot, slots) {
|
|
unsigned long start = memslot->userspace_addr;
|
|
unsigned long end;
|
|
|
|
end = start + (memslot->npages << PAGE_SHIFT);
|
|
if (hva >= start && hva < end) {
|
|
gfn_t gfn_offset = (hva - start) >> PAGE_SHIFT;
|
|
gfn_t gfn = memslot->base_gfn + gfn_offset;
|
|
|
|
ret = handler(kvm, &memslot->rmap[gfn_offset], data);
|
|
|
|
for (j = 0; j < KVM_NR_PAGE_SIZES - 1; ++j) {
|
|
struct kvm_lpage_info *linfo;
|
|
|
|
linfo = lpage_info_slot(gfn, memslot,
|
|
PT_DIRECTORY_LEVEL + j);
|
|
ret |= handler(kvm, &linfo->rmap_pde, data);
|
|
}
|
|
trace_kvm_age_page(hva, memslot, ret);
|
|
retval |= ret;
|
|
}
|
|
}
|
|
|
|
return retval;
|
|
}
|
|
|
|
int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
|
|
{
|
|
return kvm_handle_hva(kvm, hva, 0, kvm_unmap_rmapp);
|
|
}
|
|
|
|
void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
|
|
{
|
|
kvm_handle_hva(kvm, hva, (unsigned long)&pte, kvm_set_pte_rmapp);
|
|
}
|
|
|
|
static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
|
|
unsigned long data)
|
|
{
|
|
u64 *spte;
|
|
int young = 0;
|
|
|
|
/*
|
|
* Emulate the accessed bit for EPT, by checking if this page has
|
|
* an EPT mapping, and clearing it if it does. On the next access,
|
|
* a new EPT mapping will be established.
|
|
* This has some overhead, but not as much as the cost of swapping
|
|
* out actively used pages or breaking up actively used hugepages.
|
|
*/
|
|
if (!shadow_accessed_mask)
|
|
return kvm_unmap_rmapp(kvm, rmapp, data);
|
|
|
|
spte = rmap_next(rmapp, NULL);
|
|
while (spte) {
|
|
int _young;
|
|
u64 _spte = *spte;
|
|
BUG_ON(!(_spte & PT_PRESENT_MASK));
|
|
_young = _spte & PT_ACCESSED_MASK;
|
|
if (_young) {
|
|
young = 1;
|
|
clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
|
|
}
|
|
spte = rmap_next(rmapp, spte);
|
|
}
|
|
return young;
|
|
}
|
|
|
|
static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
|
|
unsigned long data)
|
|
{
|
|
u64 *spte;
|
|
int young = 0;
|
|
|
|
/*
|
|
* If there's no access bit in the secondary pte set by the
|
|
* hardware it's up to gup-fast/gup to set the access bit in
|
|
* the primary pte or in the page structure.
|
|
*/
|
|
if (!shadow_accessed_mask)
|
|
goto out;
|
|
|
|
spte = rmap_next(rmapp, NULL);
|
|
while (spte) {
|
|
u64 _spte = *spte;
|
|
BUG_ON(!(_spte & PT_PRESENT_MASK));
|
|
young = _spte & PT_ACCESSED_MASK;
|
|
if (young) {
|
|
young = 1;
|
|
break;
|
|
}
|
|
spte = rmap_next(rmapp, spte);
|
|
}
|
|
out:
|
|
return young;
|
|
}
|
|
|
|
#define RMAP_RECYCLE_THRESHOLD 1000
|
|
|
|
static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
|
|
{
|
|
unsigned long *rmapp;
|
|
struct kvm_mmu_page *sp;
|
|
|
|
sp = page_header(__pa(spte));
|
|
|
|
rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
|
|
|
|
kvm_unmap_rmapp(vcpu->kvm, rmapp, 0);
|
|
kvm_flush_remote_tlbs(vcpu->kvm);
|
|
}
|
|
|
|
int kvm_age_hva(struct kvm *kvm, unsigned long hva)
|
|
{
|
|
return kvm_handle_hva(kvm, hva, 0, kvm_age_rmapp);
|
|
}
|
|
|
|
int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
|
|
{
|
|
return kvm_handle_hva(kvm, hva, 0, kvm_test_age_rmapp);
|
|
}
|
|
|
|
#ifdef MMU_DEBUG
|
|
static int is_empty_shadow_page(u64 *spt)
|
|
{
|
|
u64 *pos;
|
|
u64 *end;
|
|
|
|
for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
|
|
if (is_shadow_present_pte(*pos)) {
|
|
printk(KERN_ERR "%s: %p %llx\n", __func__,
|
|
pos, *pos);
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* This value is the sum of all of the kvm instances's
|
|
* kvm->arch.n_used_mmu_pages values. We need a global,
|
|
* aggregate version in order to make the slab shrinker
|
|
* faster
|
|
*/
|
|
static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, int nr)
|
|
{
|
|
kvm->arch.n_used_mmu_pages += nr;
|
|
percpu_counter_add(&kvm_total_used_mmu_pages, nr);
|
|
}
|
|
|
|
/*
|
|
* Remove the sp from shadow page cache, after call it,
|
|
* we can not find this sp from the cache, and the shadow
|
|
* page table is still valid.
|
|
* It should be under the protection of mmu lock.
|
|
*/
|
|
static void kvm_mmu_isolate_page(struct kvm_mmu_page *sp)
|
|
{
|
|
ASSERT(is_empty_shadow_page(sp->spt));
|
|
hlist_del(&sp->hash_link);
|
|
if (!sp->role.direct)
|
|
free_page((unsigned long)sp->gfns);
|
|
}
|
|
|
|
/*
|
|
* Free the shadow page table and the sp, we can do it
|
|
* out of the protection of mmu lock.
|
|
*/
|
|
static void kvm_mmu_free_page(struct kvm_mmu_page *sp)
|
|
{
|
|
list_del(&sp->link);
|
|
free_page((unsigned long)sp->spt);
|
|
kmem_cache_free(mmu_page_header_cache, sp);
|
|
}
|
|
|
|
static unsigned kvm_page_table_hashfn(gfn_t gfn)
|
|
{
|
|
return gfn & ((1 << KVM_MMU_HASH_SHIFT) - 1);
|
|
}
|
|
|
|
static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
|
|
struct kvm_mmu_page *sp, u64 *parent_pte)
|
|
{
|
|
if (!parent_pte)
|
|
return;
|
|
|
|
pte_list_add(vcpu, parent_pte, &sp->parent_ptes);
|
|
}
|
|
|
|
static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
|
|
u64 *parent_pte)
|
|
{
|
|
pte_list_remove(parent_pte, &sp->parent_ptes);
|
|
}
|
|
|
|
static void drop_parent_pte(struct kvm_mmu_page *sp,
|
|
u64 *parent_pte)
|
|
{
|
|
mmu_page_remove_parent_pte(sp, parent_pte);
|
|
mmu_spte_clear_no_track(parent_pte);
|
|
}
|
|
|
|
static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
|
|
u64 *parent_pte, int direct)
|
|
{
|
|
struct kvm_mmu_page *sp;
|
|
sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache,
|
|
sizeof *sp);
|
|
sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
|
|
if (!direct)
|
|
sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache,
|
|
PAGE_SIZE);
|
|
set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
|
|
list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
|
|
bitmap_zero(sp->slot_bitmap, KVM_MEM_SLOTS_NUM);
|
|
sp->parent_ptes = 0;
|
|
mmu_page_add_parent_pte(vcpu, sp, parent_pte);
|
|
kvm_mod_used_mmu_pages(vcpu->kvm, +1);
|
|
return sp;
|
|
}
|
|
|
|
static void mark_unsync(u64 *spte);
|
|
static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp)
|
|
{
|
|
pte_list_walk(&sp->parent_ptes, mark_unsync);
|
|
}
|
|
|
|
static void mark_unsync(u64 *spte)
|
|
{
|
|
struct kvm_mmu_page *sp;
|
|
unsigned int index;
|
|
|
|
sp = page_header(__pa(spte));
|
|
index = spte - sp->spt;
|
|
if (__test_and_set_bit(index, sp->unsync_child_bitmap))
|
|
return;
|
|
if (sp->unsync_children++)
|
|
return;
|
|
kvm_mmu_mark_parents_unsync(sp);
|
|
}
|
|
|
|
static int nonpaging_sync_page(struct kvm_vcpu *vcpu,
|
|
struct kvm_mmu_page *sp)
|
|
{
|
|
return 1;
|
|
}
|
|
|
|
static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
|
|
{
|
|
}
|
|
|
|
static void nonpaging_update_pte(struct kvm_vcpu *vcpu,
|
|
struct kvm_mmu_page *sp, u64 *spte,
|
|
const void *pte)
|
|
{
|
|
WARN_ON(1);
|
|
}
|
|
|
|
#define KVM_PAGE_ARRAY_NR 16
|
|
|
|
struct kvm_mmu_pages {
|
|
struct mmu_page_and_offset {
|
|
struct kvm_mmu_page *sp;
|
|
unsigned int idx;
|
|
} page[KVM_PAGE_ARRAY_NR];
|
|
unsigned int nr;
|
|
};
|
|
|
|
static int mmu_pages_add(struct kvm_mmu_pages *pvec, struct kvm_mmu_page *sp,
|
|
int idx)
|
|
{
|
|
int i;
|
|
|
|
if (sp->unsync)
|
|
for (i=0; i < pvec->nr; i++)
|
|
if (pvec->page[i].sp == sp)
|
|
return 0;
|
|
|
|
pvec->page[pvec->nr].sp = sp;
|
|
pvec->page[pvec->nr].idx = idx;
|
|
pvec->nr++;
|
|
return (pvec->nr == KVM_PAGE_ARRAY_NR);
|
|
}
|
|
|
|
static int __mmu_unsync_walk(struct kvm_mmu_page *sp,
|
|
struct kvm_mmu_pages *pvec)
|
|
{
|
|
int i, ret, nr_unsync_leaf = 0;
|
|
|
|
for_each_set_bit(i, sp->unsync_child_bitmap, 512) {
|
|
struct kvm_mmu_page *child;
|
|
u64 ent = sp->spt[i];
|
|
|
|
if (!is_shadow_present_pte(ent) || is_large_pte(ent))
|
|
goto clear_child_bitmap;
|
|
|
|
child = page_header(ent & PT64_BASE_ADDR_MASK);
|
|
|
|
if (child->unsync_children) {
|
|
if (mmu_pages_add(pvec, child, i))
|
|
return -ENOSPC;
|
|
|
|
ret = __mmu_unsync_walk(child, pvec);
|
|
if (!ret)
|
|
goto clear_child_bitmap;
|
|
else if (ret > 0)
|
|
nr_unsync_leaf += ret;
|
|
else
|
|
return ret;
|
|
} else if (child->unsync) {
|
|
nr_unsync_leaf++;
|
|
if (mmu_pages_add(pvec, child, i))
|
|
return -ENOSPC;
|
|
} else
|
|
goto clear_child_bitmap;
|
|
|
|
continue;
|
|
|
|
clear_child_bitmap:
|
|
__clear_bit(i, sp->unsync_child_bitmap);
|
|
sp->unsync_children--;
|
|
WARN_ON((int)sp->unsync_children < 0);
|
|
}
|
|
|
|
|
|
return nr_unsync_leaf;
|
|
}
|
|
|
|
static int mmu_unsync_walk(struct kvm_mmu_page *sp,
|
|
struct kvm_mmu_pages *pvec)
|
|
{
|
|
if (!sp->unsync_children)
|
|
return 0;
|
|
|
|
mmu_pages_add(pvec, sp, 0);
|
|
return __mmu_unsync_walk(sp, pvec);
|
|
}
|
|
|
|
static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
|
|
{
|
|
WARN_ON(!sp->unsync);
|
|
trace_kvm_mmu_sync_page(sp);
|
|
sp->unsync = 0;
|
|
--kvm->stat.mmu_unsync;
|
|
}
|
|
|
|
static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
|
|
struct list_head *invalid_list);
|
|
static void kvm_mmu_commit_zap_page(struct kvm *kvm,
|
|
struct list_head *invalid_list);
|
|
|
|
#define for_each_gfn_sp(kvm, sp, gfn, pos) \
|
|
hlist_for_each_entry(sp, pos, \
|
|
&(kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)], hash_link) \
|
|
if ((sp)->gfn != (gfn)) {} else
|
|
|
|
#define for_each_gfn_indirect_valid_sp(kvm, sp, gfn, pos) \
|
|
hlist_for_each_entry(sp, pos, \
|
|
&(kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)], hash_link) \
|
|
if ((sp)->gfn != (gfn) || (sp)->role.direct || \
|
|
(sp)->role.invalid) {} else
|
|
|
|
/* @sp->gfn should be write-protected at the call site */
|
|
static int __kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
|
|
struct list_head *invalid_list, bool clear_unsync)
|
|
{
|
|
if (sp->role.cr4_pae != !!is_pae(vcpu)) {
|
|
kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list);
|
|
return 1;
|
|
}
|
|
|
|
if (clear_unsync)
|
|
kvm_unlink_unsync_page(vcpu->kvm, sp);
|
|
|
|
if (vcpu->arch.mmu.sync_page(vcpu, sp)) {
|
|
kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list);
|
|
return 1;
|
|
}
|
|
|
|
kvm_mmu_flush_tlb(vcpu);
|
|
return 0;
|
|
}
|
|
|
|
static int kvm_sync_page_transient(struct kvm_vcpu *vcpu,
|
|
struct kvm_mmu_page *sp)
|
|
{
|
|
LIST_HEAD(invalid_list);
|
|
int ret;
|
|
|
|
ret = __kvm_sync_page(vcpu, sp, &invalid_list, false);
|
|
if (ret)
|
|
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
|
|
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_KVM_MMU_AUDIT
|
|
#include "mmu_audit.c"
|
|
#else
|
|
static void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point) { }
|
|
static void mmu_audit_disable(void) { }
|
|
#endif
|
|
|
|
static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
|
|
struct list_head *invalid_list)
|
|
{
|
|
return __kvm_sync_page(vcpu, sp, invalid_list, true);
|
|
}
|
|
|
|
/* @gfn should be write-protected at the call site */
|
|
static void kvm_sync_pages(struct kvm_vcpu *vcpu, gfn_t gfn)
|
|
{
|
|
struct kvm_mmu_page *s;
|
|
struct hlist_node *node;
|
|
LIST_HEAD(invalid_list);
|
|
bool flush = false;
|
|
|
|
for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) {
|
|
if (!s->unsync)
|
|
continue;
|
|
|
|
WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL);
|
|
kvm_unlink_unsync_page(vcpu->kvm, s);
|
|
if ((s->role.cr4_pae != !!is_pae(vcpu)) ||
|
|
(vcpu->arch.mmu.sync_page(vcpu, s))) {
|
|
kvm_mmu_prepare_zap_page(vcpu->kvm, s, &invalid_list);
|
|
continue;
|
|
}
|
|
flush = true;
|
|
}
|
|
|
|
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
|
|
if (flush)
|
|
kvm_mmu_flush_tlb(vcpu);
|
|
}
|
|
|
|
struct mmu_page_path {
|
|
struct kvm_mmu_page *parent[PT64_ROOT_LEVEL-1];
|
|
unsigned int idx[PT64_ROOT_LEVEL-1];
|
|
};
|
|
|
|
#define for_each_sp(pvec, sp, parents, i) \
|
|
for (i = mmu_pages_next(&pvec, &parents, -1), \
|
|
sp = pvec.page[i].sp; \
|
|
i < pvec.nr && ({ sp = pvec.page[i].sp; 1;}); \
|
|
i = mmu_pages_next(&pvec, &parents, i))
|
|
|
|
static int mmu_pages_next(struct kvm_mmu_pages *pvec,
|
|
struct mmu_page_path *parents,
|
|
int i)
|
|
{
|
|
int n;
|
|
|
|
for (n = i+1; n < pvec->nr; n++) {
|
|
struct kvm_mmu_page *sp = pvec->page[n].sp;
|
|
|
|
if (sp->role.level == PT_PAGE_TABLE_LEVEL) {
|
|
parents->idx[0] = pvec->page[n].idx;
|
|
return n;
|
|
}
|
|
|
|
parents->parent[sp->role.level-2] = sp;
|
|
parents->idx[sp->role.level-1] = pvec->page[n].idx;
|
|
}
|
|
|
|
return n;
|
|
}
|
|
|
|
static void mmu_pages_clear_parents(struct mmu_page_path *parents)
|
|
{
|
|
struct kvm_mmu_page *sp;
|
|
unsigned int level = 0;
|
|
|
|
do {
|
|
unsigned int idx = parents->idx[level];
|
|
|
|
sp = parents->parent[level];
|
|
if (!sp)
|
|
return;
|
|
|
|
--sp->unsync_children;
|
|
WARN_ON((int)sp->unsync_children < 0);
|
|
__clear_bit(idx, sp->unsync_child_bitmap);
|
|
level++;
|
|
} while (level < PT64_ROOT_LEVEL-1 && !sp->unsync_children);
|
|
}
|
|
|
|
static void kvm_mmu_pages_init(struct kvm_mmu_page *parent,
|
|
struct mmu_page_path *parents,
|
|
struct kvm_mmu_pages *pvec)
|
|
{
|
|
parents->parent[parent->role.level-1] = NULL;
|
|
pvec->nr = 0;
|
|
}
|
|
|
|
static void mmu_sync_children(struct kvm_vcpu *vcpu,
|
|
struct kvm_mmu_page *parent)
|
|
{
|
|
int i;
|
|
struct kvm_mmu_page *sp;
|
|
struct mmu_page_path parents;
|
|
struct kvm_mmu_pages pages;
|
|
LIST_HEAD(invalid_list);
|
|
|
|
kvm_mmu_pages_init(parent, &parents, &pages);
|
|
while (mmu_unsync_walk(parent, &pages)) {
|
|
int protected = 0;
|
|
|
|
for_each_sp(pages, sp, parents, i)
|
|
protected |= rmap_write_protect(vcpu->kvm, sp->gfn);
|
|
|
|
if (protected)
|
|
kvm_flush_remote_tlbs(vcpu->kvm);
|
|
|
|
for_each_sp(pages, sp, parents, i) {
|
|
kvm_sync_page(vcpu, sp, &invalid_list);
|
|
mmu_pages_clear_parents(&parents);
|
|
}
|
|
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
|
|
cond_resched_lock(&vcpu->kvm->mmu_lock);
|
|
kvm_mmu_pages_init(parent, &parents, &pages);
|
|
}
|
|
}
|
|
|
|
static void init_shadow_page_table(struct kvm_mmu_page *sp)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
|
|
sp->spt[i] = 0ull;
|
|
}
|
|
|
|
static void __clear_sp_write_flooding_count(struct kvm_mmu_page *sp)
|
|
{
|
|
sp->write_flooding_count = 0;
|
|
}
|
|
|
|
static void clear_sp_write_flooding_count(u64 *spte)
|
|
{
|
|
struct kvm_mmu_page *sp = page_header(__pa(spte));
|
|
|
|
__clear_sp_write_flooding_count(sp);
|
|
}
|
|
|
|
static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
|
|
gfn_t gfn,
|
|
gva_t gaddr,
|
|
unsigned level,
|
|
int direct,
|
|
unsigned access,
|
|
u64 *parent_pte)
|
|
{
|
|
union kvm_mmu_page_role role;
|
|
unsigned quadrant;
|
|
struct kvm_mmu_page *sp;
|
|
struct hlist_node *node;
|
|
bool need_sync = false;
|
|
|
|
role = vcpu->arch.mmu.base_role;
|
|
role.level = level;
|
|
role.direct = direct;
|
|
if (role.direct)
|
|
role.cr4_pae = 0;
|
|
role.access = access;
|
|
if (!vcpu->arch.mmu.direct_map
|
|
&& vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) {
|
|
quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
|
|
quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
|
|
role.quadrant = quadrant;
|
|
}
|
|
for_each_gfn_sp(vcpu->kvm, sp, gfn, node) {
|
|
if (!need_sync && sp->unsync)
|
|
need_sync = true;
|
|
|
|
if (sp->role.word != role.word)
|
|
continue;
|
|
|
|
if (sp->unsync && kvm_sync_page_transient(vcpu, sp))
|
|
break;
|
|
|
|
mmu_page_add_parent_pte(vcpu, sp, parent_pte);
|
|
if (sp->unsync_children) {
|
|
kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
|
|
kvm_mmu_mark_parents_unsync(sp);
|
|
} else if (sp->unsync)
|
|
kvm_mmu_mark_parents_unsync(sp);
|
|
|
|
__clear_sp_write_flooding_count(sp);
|
|
trace_kvm_mmu_get_page(sp, false);
|
|
return sp;
|
|
}
|
|
++vcpu->kvm->stat.mmu_cache_miss;
|
|
sp = kvm_mmu_alloc_page(vcpu, parent_pte, direct);
|
|
if (!sp)
|
|
return sp;
|
|
sp->gfn = gfn;
|
|
sp->role = role;
|
|
hlist_add_head(&sp->hash_link,
|
|
&vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]);
|
|
if (!direct) {
|
|
if (rmap_write_protect(vcpu->kvm, gfn))
|
|
kvm_flush_remote_tlbs(vcpu->kvm);
|
|
if (level > PT_PAGE_TABLE_LEVEL && need_sync)
|
|
kvm_sync_pages(vcpu, gfn);
|
|
|
|
account_shadowed(vcpu->kvm, gfn);
|
|
}
|
|
init_shadow_page_table(sp);
|
|
trace_kvm_mmu_get_page(sp, true);
|
|
return sp;
|
|
}
|
|
|
|
static void shadow_walk_init(struct kvm_shadow_walk_iterator *iterator,
|
|
struct kvm_vcpu *vcpu, u64 addr)
|
|
{
|
|
iterator->addr = addr;
|
|
iterator->shadow_addr = vcpu->arch.mmu.root_hpa;
|
|
iterator->level = vcpu->arch.mmu.shadow_root_level;
|
|
|
|
if (iterator->level == PT64_ROOT_LEVEL &&
|
|
vcpu->arch.mmu.root_level < PT64_ROOT_LEVEL &&
|
|
!vcpu->arch.mmu.direct_map)
|
|
--iterator->level;
|
|
|
|
if (iterator->level == PT32E_ROOT_LEVEL) {
|
|
iterator->shadow_addr
|
|
= vcpu->arch.mmu.pae_root[(addr >> 30) & 3];
|
|
iterator->shadow_addr &= PT64_BASE_ADDR_MASK;
|
|
--iterator->level;
|
|
if (!iterator->shadow_addr)
|
|
iterator->level = 0;
|
|
}
|
|
}
|
|
|
|
static bool shadow_walk_okay(struct kvm_shadow_walk_iterator *iterator)
|
|
{
|
|
if (iterator->level < PT_PAGE_TABLE_LEVEL)
|
|
return false;
|
|
|
|
iterator->index = SHADOW_PT_INDEX(iterator->addr, iterator->level);
|
|
iterator->sptep = ((u64 *)__va(iterator->shadow_addr)) + iterator->index;
|
|
return true;
|
|
}
|
|
|
|
static void __shadow_walk_next(struct kvm_shadow_walk_iterator *iterator,
|
|
u64 spte)
|
|
{
|
|
if (is_last_spte(spte, iterator->level)) {
|
|
iterator->level = 0;
|
|
return;
|
|
}
|
|
|
|
iterator->shadow_addr = spte & PT64_BASE_ADDR_MASK;
|
|
--iterator->level;
|
|
}
|
|
|
|
static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
|
|
{
|
|
return __shadow_walk_next(iterator, *iterator->sptep);
|
|
}
|
|
|
|
static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp)
|
|
{
|
|
u64 spte;
|
|
|
|
spte = __pa(sp->spt)
|
|
| PT_PRESENT_MASK | PT_ACCESSED_MASK
|
|
| PT_WRITABLE_MASK | PT_USER_MASK;
|
|
mmu_spte_set(sptep, spte);
|
|
}
|
|
|
|
static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep)
|
|
{
|
|
if (is_large_pte(*sptep)) {
|
|
drop_spte(vcpu->kvm, sptep);
|
|
--vcpu->kvm->stat.lpages;
|
|
kvm_flush_remote_tlbs(vcpu->kvm);
|
|
}
|
|
}
|
|
|
|
static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep,
|
|
unsigned direct_access)
|
|
{
|
|
if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep)) {
|
|
struct kvm_mmu_page *child;
|
|
|
|
/*
|
|
* For the direct sp, if the guest pte's dirty bit
|
|
* changed form clean to dirty, it will corrupt the
|
|
* sp's access: allow writable in the read-only sp,
|
|
* so we should update the spte at this point to get
|
|
* a new sp with the correct access.
|
|
*/
|
|
child = page_header(*sptep & PT64_BASE_ADDR_MASK);
|
|
if (child->role.access == direct_access)
|
|
return;
|
|
|
|
drop_parent_pte(child, sptep);
|
|
kvm_flush_remote_tlbs(vcpu->kvm);
|
|
}
|
|
}
|
|
|
|
static bool mmu_page_zap_pte(struct kvm *kvm, struct kvm_mmu_page *sp,
|
|
u64 *spte)
|
|
{
|
|
u64 pte;
|
|
struct kvm_mmu_page *child;
|
|
|
|
pte = *spte;
|
|
if (is_shadow_present_pte(pte)) {
|
|
if (is_last_spte(pte, sp->role.level)) {
|
|
drop_spte(kvm, spte);
|
|
if (is_large_pte(pte))
|
|
--kvm->stat.lpages;
|
|
} else {
|
|
child = page_header(pte & PT64_BASE_ADDR_MASK);
|
|
drop_parent_pte(child, spte);
|
|
}
|
|
return true;
|
|
}
|
|
|
|
if (is_mmio_spte(pte))
|
|
mmu_spte_clear_no_track(spte);
|
|
|
|
return false;
|
|
}
|
|
|
|
static void kvm_mmu_page_unlink_children(struct kvm *kvm,
|
|
struct kvm_mmu_page *sp)
|
|
{
|
|
unsigned i;
|
|
|
|
for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
|
|
mmu_page_zap_pte(kvm, sp, sp->spt + i);
|
|
}
|
|
|
|
static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
|
|
{
|
|
mmu_page_remove_parent_pte(sp, parent_pte);
|
|
}
|
|
|
|
static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
|
|
{
|
|
u64 *parent_pte;
|
|
|
|
while ((parent_pte = pte_list_next(&sp->parent_ptes, NULL)))
|
|
drop_parent_pte(sp, parent_pte);
|
|
}
|
|
|
|
static int mmu_zap_unsync_children(struct kvm *kvm,
|
|
struct kvm_mmu_page *parent,
|
|
struct list_head *invalid_list)
|
|
{
|
|
int i, zapped = 0;
|
|
struct mmu_page_path parents;
|
|
struct kvm_mmu_pages pages;
|
|
|
|
if (parent->role.level == PT_PAGE_TABLE_LEVEL)
|
|
return 0;
|
|
|
|
kvm_mmu_pages_init(parent, &parents, &pages);
|
|
while (mmu_unsync_walk(parent, &pages)) {
|
|
struct kvm_mmu_page *sp;
|
|
|
|
for_each_sp(pages, sp, parents, i) {
|
|
kvm_mmu_prepare_zap_page(kvm, sp, invalid_list);
|
|
mmu_pages_clear_parents(&parents);
|
|
zapped++;
|
|
}
|
|
kvm_mmu_pages_init(parent, &parents, &pages);
|
|
}
|
|
|
|
return zapped;
|
|
}
|
|
|
|
static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
|
|
struct list_head *invalid_list)
|
|
{
|
|
int ret;
|
|
|
|
trace_kvm_mmu_prepare_zap_page(sp);
|
|
++kvm->stat.mmu_shadow_zapped;
|
|
ret = mmu_zap_unsync_children(kvm, sp, invalid_list);
|
|
kvm_mmu_page_unlink_children(kvm, sp);
|
|
kvm_mmu_unlink_parents(kvm, sp);
|
|
if (!sp->role.invalid && !sp->role.direct)
|
|
unaccount_shadowed(kvm, sp->gfn);
|
|
if (sp->unsync)
|
|
kvm_unlink_unsync_page(kvm, sp);
|
|
if (!sp->root_count) {
|
|
/* Count self */
|
|
ret++;
|
|
list_move(&sp->link, invalid_list);
|
|
kvm_mod_used_mmu_pages(kvm, -1);
|
|
} else {
|
|
list_move(&sp->link, &kvm->arch.active_mmu_pages);
|
|
kvm_reload_remote_mmus(kvm);
|
|
}
|
|
|
|
sp->role.invalid = 1;
|
|
return ret;
|
|
}
|
|
|
|
static void kvm_mmu_isolate_pages(struct list_head *invalid_list)
|
|
{
|
|
struct kvm_mmu_page *sp;
|
|
|
|
list_for_each_entry(sp, invalid_list, link)
|
|
kvm_mmu_isolate_page(sp);
|
|
}
|
|
|
|
static void free_pages_rcu(struct rcu_head *head)
|
|
{
|
|
struct kvm_mmu_page *next, *sp;
|
|
|
|
sp = container_of(head, struct kvm_mmu_page, rcu);
|
|
while (sp) {
|
|
if (!list_empty(&sp->link))
|
|
next = list_first_entry(&sp->link,
|
|
struct kvm_mmu_page, link);
|
|
else
|
|
next = NULL;
|
|
kvm_mmu_free_page(sp);
|
|
sp = next;
|
|
}
|
|
}
|
|
|
|
static void kvm_mmu_commit_zap_page(struct kvm *kvm,
|
|
struct list_head *invalid_list)
|
|
{
|
|
struct kvm_mmu_page *sp;
|
|
|
|
if (list_empty(invalid_list))
|
|
return;
|
|
|
|
kvm_flush_remote_tlbs(kvm);
|
|
|
|
if (atomic_read(&kvm->arch.reader_counter)) {
|
|
kvm_mmu_isolate_pages(invalid_list);
|
|
sp = list_first_entry(invalid_list, struct kvm_mmu_page, link);
|
|
list_del_init(invalid_list);
|
|
|
|
trace_kvm_mmu_delay_free_pages(sp);
|
|
call_rcu(&sp->rcu, free_pages_rcu);
|
|
return;
|
|
}
|
|
|
|
do {
|
|
sp = list_first_entry(invalid_list, struct kvm_mmu_page, link);
|
|
WARN_ON(!sp->role.invalid || sp->root_count);
|
|
kvm_mmu_isolate_page(sp);
|
|
kvm_mmu_free_page(sp);
|
|
} while (!list_empty(invalid_list));
|
|
|
|
}
|
|
|
|
/*
|
|
* Changing the number of mmu pages allocated to the vm
|
|
* Note: if goal_nr_mmu_pages is too small, you will get dead lock
|
|
*/
|
|
void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages)
|
|
{
|
|
LIST_HEAD(invalid_list);
|
|
/*
|
|
* If we set the number of mmu pages to be smaller be than the
|
|
* number of actived pages , we must to free some mmu pages before we
|
|
* change the value
|
|
*/
|
|
|
|
if (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages) {
|
|
while (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages &&
|
|
!list_empty(&kvm->arch.active_mmu_pages)) {
|
|
struct kvm_mmu_page *page;
|
|
|
|
page = container_of(kvm->arch.active_mmu_pages.prev,
|
|
struct kvm_mmu_page, link);
|
|
kvm_mmu_prepare_zap_page(kvm, page, &invalid_list);
|
|
}
|
|
kvm_mmu_commit_zap_page(kvm, &invalid_list);
|
|
goal_nr_mmu_pages = kvm->arch.n_used_mmu_pages;
|
|
}
|
|
|
|
kvm->arch.n_max_mmu_pages = goal_nr_mmu_pages;
|
|
}
|
|
|
|
int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
|
|
{
|
|
struct kvm_mmu_page *sp;
|
|
struct hlist_node *node;
|
|
LIST_HEAD(invalid_list);
|
|
int r;
|
|
|
|
pgprintk("%s: looking for gfn %llx\n", __func__, gfn);
|
|
r = 0;
|
|
spin_lock(&kvm->mmu_lock);
|
|
for_each_gfn_indirect_valid_sp(kvm, sp, gfn, node) {
|
|
pgprintk("%s: gfn %llx role %x\n", __func__, gfn,
|
|
sp->role.word);
|
|
r = 1;
|
|
kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
|
|
}
|
|
kvm_mmu_commit_zap_page(kvm, &invalid_list);
|
|
spin_unlock(&kvm->mmu_lock);
|
|
|
|
return r;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page);
|
|
|
|
static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn)
|
|
{
|
|
int slot = memslot_id(kvm, gfn);
|
|
struct kvm_mmu_page *sp = page_header(__pa(pte));
|
|
|
|
__set_bit(slot, sp->slot_bitmap);
|
|
}
|
|
|
|
/*
|
|
* The function is based on mtrr_type_lookup() in
|
|
* arch/x86/kernel/cpu/mtrr/generic.c
|
|
*/
|
|
static int get_mtrr_type(struct mtrr_state_type *mtrr_state,
|
|
u64 start, u64 end)
|
|
{
|
|
int i;
|
|
u64 base, mask;
|
|
u8 prev_match, curr_match;
|
|
int num_var_ranges = KVM_NR_VAR_MTRR;
|
|
|
|
if (!mtrr_state->enabled)
|
|
return 0xFF;
|
|
|
|
/* Make end inclusive end, instead of exclusive */
|
|
end--;
|
|
|
|
/* Look in fixed ranges. Just return the type as per start */
|
|
if (mtrr_state->have_fixed && (start < 0x100000)) {
|
|
int idx;
|
|
|
|
if (start < 0x80000) {
|
|
idx = 0;
|
|
idx += (start >> 16);
|
|
return mtrr_state->fixed_ranges[idx];
|
|
} else if (start < 0xC0000) {
|
|
idx = 1 * 8;
|
|
idx += ((start - 0x80000) >> 14);
|
|
return mtrr_state->fixed_ranges[idx];
|
|
} else if (start < 0x1000000) {
|
|
idx = 3 * 8;
|
|
idx += ((start - 0xC0000) >> 12);
|
|
return mtrr_state->fixed_ranges[idx];
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Look in variable ranges
|
|
* Look of multiple ranges matching this address and pick type
|
|
* as per MTRR precedence
|
|
*/
|
|
if (!(mtrr_state->enabled & 2))
|
|
return mtrr_state->def_type;
|
|
|
|
prev_match = 0xFF;
|
|
for (i = 0; i < num_var_ranges; ++i) {
|
|
unsigned short start_state, end_state;
|
|
|
|
if (!(mtrr_state->var_ranges[i].mask_lo & (1 << 11)))
|
|
continue;
|
|
|
|
base = (((u64)mtrr_state->var_ranges[i].base_hi) << 32) +
|
|
(mtrr_state->var_ranges[i].base_lo & PAGE_MASK);
|
|
mask = (((u64)mtrr_state->var_ranges[i].mask_hi) << 32) +
|
|
(mtrr_state->var_ranges[i].mask_lo & PAGE_MASK);
|
|
|
|
start_state = ((start & mask) == (base & mask));
|
|
end_state = ((end & mask) == (base & mask));
|
|
if (start_state != end_state)
|
|
return 0xFE;
|
|
|
|
if ((start & mask) != (base & mask))
|
|
continue;
|
|
|
|
curr_match = mtrr_state->var_ranges[i].base_lo & 0xff;
|
|
if (prev_match == 0xFF) {
|
|
prev_match = curr_match;
|
|
continue;
|
|
}
|
|
|
|
if (prev_match == MTRR_TYPE_UNCACHABLE ||
|
|
curr_match == MTRR_TYPE_UNCACHABLE)
|
|
return MTRR_TYPE_UNCACHABLE;
|
|
|
|
if ((prev_match == MTRR_TYPE_WRBACK &&
|
|
curr_match == MTRR_TYPE_WRTHROUGH) ||
|
|
(prev_match == MTRR_TYPE_WRTHROUGH &&
|
|
curr_match == MTRR_TYPE_WRBACK)) {
|
|
prev_match = MTRR_TYPE_WRTHROUGH;
|
|
curr_match = MTRR_TYPE_WRTHROUGH;
|
|
}
|
|
|
|
if (prev_match != curr_match)
|
|
return MTRR_TYPE_UNCACHABLE;
|
|
}
|
|
|
|
if (prev_match != 0xFF)
|
|
return prev_match;
|
|
|
|
return mtrr_state->def_type;
|
|
}
|
|
|
|
u8 kvm_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
|
|
{
|
|
u8 mtrr;
|
|
|
|
mtrr = get_mtrr_type(&vcpu->arch.mtrr_state, gfn << PAGE_SHIFT,
|
|
(gfn << PAGE_SHIFT) + PAGE_SIZE);
|
|
if (mtrr == 0xfe || mtrr == 0xff)
|
|
mtrr = MTRR_TYPE_WRBACK;
|
|
return mtrr;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kvm_get_guest_memory_type);
|
|
|
|
static void __kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
|
|
{
|
|
trace_kvm_mmu_unsync_page(sp);
|
|
++vcpu->kvm->stat.mmu_unsync;
|
|
sp->unsync = 1;
|
|
|
|
kvm_mmu_mark_parents_unsync(sp);
|
|
}
|
|
|
|
static void kvm_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn)
|
|
{
|
|
struct kvm_mmu_page *s;
|
|
struct hlist_node *node;
|
|
|
|
for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) {
|
|
if (s->unsync)
|
|
continue;
|
|
WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL);
|
|
__kvm_unsync_page(vcpu, s);
|
|
}
|
|
}
|
|
|
|
static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
|
|
bool can_unsync)
|
|
{
|
|
struct kvm_mmu_page *s;
|
|
struct hlist_node *node;
|
|
bool need_unsync = false;
|
|
|
|
for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) {
|
|
if (!can_unsync)
|
|
return 1;
|
|
|
|
if (s->role.level != PT_PAGE_TABLE_LEVEL)
|
|
return 1;
|
|
|
|
if (!need_unsync && !s->unsync) {
|
|
need_unsync = true;
|
|
}
|
|
}
|
|
if (need_unsync)
|
|
kvm_unsync_pages(vcpu, gfn);
|
|
return 0;
|
|
}
|
|
|
|
static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
|
|
unsigned pte_access, int user_fault,
|
|
int write_fault, int level,
|
|
gfn_t gfn, pfn_t pfn, bool speculative,
|
|
bool can_unsync, bool host_writable)
|
|
{
|
|
u64 spte, entry = *sptep;
|
|
int ret = 0;
|
|
|
|
if (set_mmio_spte(sptep, gfn, pfn, pte_access))
|
|
return 0;
|
|
|
|
spte = PT_PRESENT_MASK;
|
|
if (!speculative)
|
|
spte |= shadow_accessed_mask;
|
|
|
|
if (pte_access & ACC_EXEC_MASK)
|
|
spte |= shadow_x_mask;
|
|
else
|
|
spte |= shadow_nx_mask;
|
|
if (pte_access & ACC_USER_MASK)
|
|
spte |= shadow_user_mask;
|
|
if (level > PT_PAGE_TABLE_LEVEL)
|
|
spte |= PT_PAGE_SIZE_MASK;
|
|
if (tdp_enabled)
|
|
spte |= kvm_x86_ops->get_mt_mask(vcpu, gfn,
|
|
kvm_is_mmio_pfn(pfn));
|
|
|
|
if (host_writable)
|
|
spte |= SPTE_HOST_WRITEABLE;
|
|
else
|
|
pte_access &= ~ACC_WRITE_MASK;
|
|
|
|
spte |= (u64)pfn << PAGE_SHIFT;
|
|
|
|
if ((pte_access & ACC_WRITE_MASK)
|
|
|| (!vcpu->arch.mmu.direct_map && write_fault
|
|
&& !is_write_protection(vcpu) && !user_fault)) {
|
|
|
|
if (level > PT_PAGE_TABLE_LEVEL &&
|
|
has_wrprotected_page(vcpu->kvm, gfn, level)) {
|
|
ret = 1;
|
|
drop_spte(vcpu->kvm, sptep);
|
|
goto done;
|
|
}
|
|
|
|
spte |= PT_WRITABLE_MASK;
|
|
|
|
if (!vcpu->arch.mmu.direct_map
|
|
&& !(pte_access & ACC_WRITE_MASK)) {
|
|
spte &= ~PT_USER_MASK;
|
|
/*
|
|
* If we converted a user page to a kernel page,
|
|
* so that the kernel can write to it when cr0.wp=0,
|
|
* then we should prevent the kernel from executing it
|
|
* if SMEP is enabled.
|
|
*/
|
|
if (kvm_read_cr4_bits(vcpu, X86_CR4_SMEP))
|
|
spte |= PT64_NX_MASK;
|
|
}
|
|
|
|
/*
|
|
* Optimization: for pte sync, if spte was writable the hash
|
|
* lookup is unnecessary (and expensive). Write protection
|
|
* is responsibility of mmu_get_page / kvm_sync_page.
|
|
* Same reasoning can be applied to dirty page accounting.
|
|
*/
|
|
if (!can_unsync && is_writable_pte(*sptep))
|
|
goto set_pte;
|
|
|
|
if (mmu_need_write_protect(vcpu, gfn, can_unsync)) {
|
|
pgprintk("%s: found shadow page for %llx, marking ro\n",
|
|
__func__, gfn);
|
|
ret = 1;
|
|
pte_access &= ~ACC_WRITE_MASK;
|
|
if (is_writable_pte(spte))
|
|
spte &= ~PT_WRITABLE_MASK;
|
|
}
|
|
}
|
|
|
|
if (pte_access & ACC_WRITE_MASK)
|
|
mark_page_dirty(vcpu->kvm, gfn);
|
|
|
|
set_pte:
|
|
mmu_spte_update(sptep, spte);
|
|
/*
|
|
* If we overwrite a writable spte with a read-only one we
|
|
* should flush remote TLBs. Otherwise rmap_write_protect
|
|
* will find a read-only spte, even though the writable spte
|
|
* might be cached on a CPU's TLB.
|
|
*/
|
|
if (is_writable_pte(entry) && !is_writable_pte(*sptep))
|
|
kvm_flush_remote_tlbs(vcpu->kvm);
|
|
done:
|
|
return ret;
|
|
}
|
|
|
|
static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
|
|
unsigned pt_access, unsigned pte_access,
|
|
int user_fault, int write_fault,
|
|
int *emulate, int level, gfn_t gfn,
|
|
pfn_t pfn, bool speculative,
|
|
bool host_writable)
|
|
{
|
|
int was_rmapped = 0;
|
|
int rmap_count;
|
|
|
|
pgprintk("%s: spte %llx access %x write_fault %d"
|
|
" user_fault %d gfn %llx\n",
|
|
__func__, *sptep, pt_access,
|
|
write_fault, user_fault, gfn);
|
|
|
|
if (is_rmap_spte(*sptep)) {
|
|
/*
|
|
* If we overwrite a PTE page pointer with a 2MB PMD, unlink
|
|
* the parent of the now unreachable PTE.
|
|
*/
|
|
if (level > PT_PAGE_TABLE_LEVEL &&
|
|
!is_large_pte(*sptep)) {
|
|
struct kvm_mmu_page *child;
|
|
u64 pte = *sptep;
|
|
|
|
child = page_header(pte & PT64_BASE_ADDR_MASK);
|
|
drop_parent_pte(child, sptep);
|
|
kvm_flush_remote_tlbs(vcpu->kvm);
|
|
} else if (pfn != spte_to_pfn(*sptep)) {
|
|
pgprintk("hfn old %llx new %llx\n",
|
|
spte_to_pfn(*sptep), pfn);
|
|
drop_spte(vcpu->kvm, sptep);
|
|
kvm_flush_remote_tlbs(vcpu->kvm);
|
|
} else
|
|
was_rmapped = 1;
|
|
}
|
|
|
|
if (set_spte(vcpu, sptep, pte_access, user_fault, write_fault,
|
|
level, gfn, pfn, speculative, true,
|
|
host_writable)) {
|
|
if (write_fault)
|
|
*emulate = 1;
|
|
kvm_mmu_flush_tlb(vcpu);
|
|
}
|
|
|
|
if (unlikely(is_mmio_spte(*sptep) && emulate))
|
|
*emulate = 1;
|
|
|
|
pgprintk("%s: setting spte %llx\n", __func__, *sptep);
|
|
pgprintk("instantiating %s PTE (%s) at %llx (%llx) addr %p\n",
|
|
is_large_pte(*sptep)? "2MB" : "4kB",
|
|
*sptep & PT_PRESENT_MASK ?"RW":"R", gfn,
|
|
*sptep, sptep);
|
|
if (!was_rmapped && is_large_pte(*sptep))
|
|
++vcpu->kvm->stat.lpages;
|
|
|
|
if (is_shadow_present_pte(*sptep)) {
|
|
page_header_update_slot(vcpu->kvm, sptep, gfn);
|
|
if (!was_rmapped) {
|
|
rmap_count = rmap_add(vcpu, sptep, gfn);
|
|
if (rmap_count > RMAP_RECYCLE_THRESHOLD)
|
|
rmap_recycle(vcpu, sptep, gfn);
|
|
}
|
|
}
|
|
kvm_release_pfn_clean(pfn);
|
|
}
|
|
|
|
static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
|
|
{
|
|
}
|
|
|
|
static pfn_t pte_prefetch_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn,
|
|
bool no_dirty_log)
|
|
{
|
|
struct kvm_memory_slot *slot;
|
|
unsigned long hva;
|
|
|
|
slot = gfn_to_memslot_dirty_bitmap(vcpu, gfn, no_dirty_log);
|
|
if (!slot) {
|
|
get_page(fault_page);
|
|
return page_to_pfn(fault_page);
|
|
}
|
|
|
|
hva = gfn_to_hva_memslot(slot, gfn);
|
|
|
|
return hva_to_pfn_atomic(vcpu->kvm, hva);
|
|
}
|
|
|
|
static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu,
|
|
struct kvm_mmu_page *sp,
|
|
u64 *start, u64 *end)
|
|
{
|
|
struct page *pages[PTE_PREFETCH_NUM];
|
|
unsigned access = sp->role.access;
|
|
int i, ret;
|
|
gfn_t gfn;
|
|
|
|
gfn = kvm_mmu_page_get_gfn(sp, start - sp->spt);
|
|
if (!gfn_to_memslot_dirty_bitmap(vcpu, gfn, access & ACC_WRITE_MASK))
|
|
return -1;
|
|
|
|
ret = gfn_to_page_many_atomic(vcpu->kvm, gfn, pages, end - start);
|
|
if (ret <= 0)
|
|
return -1;
|
|
|
|
for (i = 0; i < ret; i++, gfn++, start++)
|
|
mmu_set_spte(vcpu, start, ACC_ALL,
|
|
access, 0, 0, NULL,
|
|
sp->role.level, gfn,
|
|
page_to_pfn(pages[i]), true, true);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void __direct_pte_prefetch(struct kvm_vcpu *vcpu,
|
|
struct kvm_mmu_page *sp, u64 *sptep)
|
|
{
|
|
u64 *spte, *start = NULL;
|
|
int i;
|
|
|
|
WARN_ON(!sp->role.direct);
|
|
|
|
i = (sptep - sp->spt) & ~(PTE_PREFETCH_NUM - 1);
|
|
spte = sp->spt + i;
|
|
|
|
for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) {
|
|
if (is_shadow_present_pte(*spte) || spte == sptep) {
|
|
if (!start)
|
|
continue;
|
|
if (direct_pte_prefetch_many(vcpu, sp, start, spte) < 0)
|
|
break;
|
|
start = NULL;
|
|
} else if (!start)
|
|
start = spte;
|
|
}
|
|
}
|
|
|
|
static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep)
|
|
{
|
|
struct kvm_mmu_page *sp;
|
|
|
|
/*
|
|
* Since it's no accessed bit on EPT, it's no way to
|
|
* distinguish between actually accessed translations
|
|
* and prefetched, so disable pte prefetch if EPT is
|
|
* enabled.
|
|
*/
|
|
if (!shadow_accessed_mask)
|
|
return;
|
|
|
|
sp = page_header(__pa(sptep));
|
|
if (sp->role.level > PT_PAGE_TABLE_LEVEL)
|
|
return;
|
|
|
|
__direct_pte_prefetch(vcpu, sp, sptep);
|
|
}
|
|
|
|
static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
|
|
int map_writable, int level, gfn_t gfn, pfn_t pfn,
|
|
bool prefault)
|
|
{
|
|
struct kvm_shadow_walk_iterator iterator;
|
|
struct kvm_mmu_page *sp;
|
|
int emulate = 0;
|
|
gfn_t pseudo_gfn;
|
|
|
|
for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
|
|
if (iterator.level == level) {
|
|
unsigned pte_access = ACC_ALL;
|
|
|
|
mmu_set_spte(vcpu, iterator.sptep, ACC_ALL, pte_access,
|
|
0, write, &emulate,
|
|
level, gfn, pfn, prefault, map_writable);
|
|
direct_pte_prefetch(vcpu, iterator.sptep);
|
|
++vcpu->stat.pf_fixed;
|
|
break;
|
|
}
|
|
|
|
if (!is_shadow_present_pte(*iterator.sptep)) {
|
|
u64 base_addr = iterator.addr;
|
|
|
|
base_addr &= PT64_LVL_ADDR_MASK(iterator.level);
|
|
pseudo_gfn = base_addr >> PAGE_SHIFT;
|
|
sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr,
|
|
iterator.level - 1,
|
|
1, ACC_ALL, iterator.sptep);
|
|
if (!sp) {
|
|
pgprintk("nonpaging_map: ENOMEM\n");
|
|
kvm_release_pfn_clean(pfn);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
mmu_spte_set(iterator.sptep,
|
|
__pa(sp->spt)
|
|
| PT_PRESENT_MASK | PT_WRITABLE_MASK
|
|
| shadow_user_mask | shadow_x_mask
|
|
| shadow_accessed_mask);
|
|
}
|
|
}
|
|
return emulate;
|
|
}
|
|
|
|
static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *tsk)
|
|
{
|
|
siginfo_t info;
|
|
|
|
info.si_signo = SIGBUS;
|
|
info.si_errno = 0;
|
|
info.si_code = BUS_MCEERR_AR;
|
|
info.si_addr = (void __user *)address;
|
|
info.si_addr_lsb = PAGE_SHIFT;
|
|
|
|
send_sig_info(SIGBUS, &info, tsk);
|
|
}
|
|
|
|
static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, pfn_t pfn)
|
|
{
|
|
kvm_release_pfn_clean(pfn);
|
|
if (is_hwpoison_pfn(pfn)) {
|
|
kvm_send_hwpoison_signal(gfn_to_hva(vcpu->kvm, gfn), current);
|
|
return 0;
|
|
}
|
|
|
|
return -EFAULT;
|
|
}
|
|
|
|
static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu,
|
|
gfn_t *gfnp, pfn_t *pfnp, int *levelp)
|
|
{
|
|
pfn_t pfn = *pfnp;
|
|
gfn_t gfn = *gfnp;
|
|
int level = *levelp;
|
|
|
|
/*
|
|
* Check if it's a transparent hugepage. If this would be an
|
|
* hugetlbfs page, level wouldn't be set to
|
|
* PT_PAGE_TABLE_LEVEL and there would be no adjustment done
|
|
* here.
|
|
*/
|
|
if (!is_error_pfn(pfn) && !kvm_is_mmio_pfn(pfn) &&
|
|
level == PT_PAGE_TABLE_LEVEL &&
|
|
PageTransCompound(pfn_to_page(pfn)) &&
|
|
!has_wrprotected_page(vcpu->kvm, gfn, PT_DIRECTORY_LEVEL)) {
|
|
unsigned long mask;
|
|
/*
|
|
* mmu_notifier_retry was successful and we hold the
|
|
* mmu_lock here, so the pmd can't become splitting
|
|
* from under us, and in turn
|
|
* __split_huge_page_refcount() can't run from under
|
|
* us and we can safely transfer the refcount from
|
|
* PG_tail to PG_head as we switch the pfn to tail to
|
|
* head.
|
|
*/
|
|
*levelp = level = PT_DIRECTORY_LEVEL;
|
|
mask = KVM_PAGES_PER_HPAGE(level) - 1;
|
|
VM_BUG_ON((gfn & mask) != (pfn & mask));
|
|
if (pfn & mask) {
|
|
gfn &= ~mask;
|
|
*gfnp = gfn;
|
|
kvm_release_pfn_clean(pfn);
|
|
pfn &= ~mask;
|
|
if (!get_page_unless_zero(pfn_to_page(pfn)))
|
|
BUG();
|
|
*pfnp = pfn;
|
|
}
|
|
}
|
|
}
|
|
|
|
static bool mmu_invalid_pfn(pfn_t pfn)
|
|
{
|
|
return unlikely(is_invalid_pfn(pfn));
|
|
}
|
|
|
|
static bool handle_abnormal_pfn(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
|
|
pfn_t pfn, unsigned access, int *ret_val)
|
|
{
|
|
bool ret = true;
|
|
|
|
/* The pfn is invalid, report the error! */
|
|
if (unlikely(is_invalid_pfn(pfn))) {
|
|
*ret_val = kvm_handle_bad_page(vcpu, gfn, pfn);
|
|
goto exit;
|
|
}
|
|
|
|
if (unlikely(is_noslot_pfn(pfn)))
|
|
vcpu_cache_mmio_info(vcpu, gva, gfn, access);
|
|
|
|
ret = false;
|
|
exit:
|
|
return ret;
|
|
}
|
|
|
|
static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
|
|
gva_t gva, pfn_t *pfn, bool write, bool *writable);
|
|
|
|
static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn,
|
|
bool prefault)
|
|
{
|
|
int r;
|
|
int level;
|
|
int force_pt_level;
|
|
pfn_t pfn;
|
|
unsigned long mmu_seq;
|
|
bool map_writable;
|
|
|
|
force_pt_level = mapping_level_dirty_bitmap(vcpu, gfn);
|
|
if (likely(!force_pt_level)) {
|
|
level = mapping_level(vcpu, gfn);
|
|
/*
|
|
* This path builds a PAE pagetable - so we can map
|
|
* 2mb pages at maximum. Therefore check if the level
|
|
* is larger than that.
|
|
*/
|
|
if (level > PT_DIRECTORY_LEVEL)
|
|
level = PT_DIRECTORY_LEVEL;
|
|
|
|
gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
|
|
} else
|
|
level = PT_PAGE_TABLE_LEVEL;
|
|
|
|
mmu_seq = vcpu->kvm->mmu_notifier_seq;
|
|
smp_rmb();
|
|
|
|
if (try_async_pf(vcpu, prefault, gfn, v, &pfn, write, &map_writable))
|
|
return 0;
|
|
|
|
if (handle_abnormal_pfn(vcpu, v, gfn, pfn, ACC_ALL, &r))
|
|
return r;
|
|
|
|
spin_lock(&vcpu->kvm->mmu_lock);
|
|
if (mmu_notifier_retry(vcpu, mmu_seq))
|
|
goto out_unlock;
|
|
kvm_mmu_free_some_pages(vcpu);
|
|
if (likely(!force_pt_level))
|
|
transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
|
|
r = __direct_map(vcpu, v, write, map_writable, level, gfn, pfn,
|
|
prefault);
|
|
spin_unlock(&vcpu->kvm->mmu_lock);
|
|
|
|
|
|
return r;
|
|
|
|
out_unlock:
|
|
spin_unlock(&vcpu->kvm->mmu_lock);
|
|
kvm_release_pfn_clean(pfn);
|
|
return 0;
|
|
}
|
|
|
|
|
|
static void mmu_free_roots(struct kvm_vcpu *vcpu)
|
|
{
|
|
int i;
|
|
struct kvm_mmu_page *sp;
|
|
LIST_HEAD(invalid_list);
|
|
|
|
if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
|
|
return;
|
|
spin_lock(&vcpu->kvm->mmu_lock);
|
|
if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL &&
|
|
(vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL ||
|
|
vcpu->arch.mmu.direct_map)) {
|
|
hpa_t root = vcpu->arch.mmu.root_hpa;
|
|
|
|
sp = page_header(root);
|
|
--sp->root_count;
|
|
if (!sp->root_count && sp->role.invalid) {
|
|
kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list);
|
|
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
|
|
}
|
|
vcpu->arch.mmu.root_hpa = INVALID_PAGE;
|
|
spin_unlock(&vcpu->kvm->mmu_lock);
|
|
return;
|
|
}
|
|
for (i = 0; i < 4; ++i) {
|
|
hpa_t root = vcpu->arch.mmu.pae_root[i];
|
|
|
|
if (root) {
|
|
root &= PT64_BASE_ADDR_MASK;
|
|
sp = page_header(root);
|
|
--sp->root_count;
|
|
if (!sp->root_count && sp->role.invalid)
|
|
kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
|
|
&invalid_list);
|
|
}
|
|
vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
|
|
}
|
|
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
|
|
spin_unlock(&vcpu->kvm->mmu_lock);
|
|
vcpu->arch.mmu.root_hpa = INVALID_PAGE;
|
|
}
|
|
|
|
static int mmu_check_root(struct kvm_vcpu *vcpu, gfn_t root_gfn)
|
|
{
|
|
int ret = 0;
|
|
|
|
if (!kvm_is_visible_gfn(vcpu->kvm, root_gfn)) {
|
|
kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
|
|
ret = 1;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
|
|
{
|
|
struct kvm_mmu_page *sp;
|
|
unsigned i;
|
|
|
|
if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
|
|
spin_lock(&vcpu->kvm->mmu_lock);
|
|
kvm_mmu_free_some_pages(vcpu);
|
|
sp = kvm_mmu_get_page(vcpu, 0, 0, PT64_ROOT_LEVEL,
|
|
1, ACC_ALL, NULL);
|
|
++sp->root_count;
|
|
spin_unlock(&vcpu->kvm->mmu_lock);
|
|
vcpu->arch.mmu.root_hpa = __pa(sp->spt);
|
|
} else if (vcpu->arch.mmu.shadow_root_level == PT32E_ROOT_LEVEL) {
|
|
for (i = 0; i < 4; ++i) {
|
|
hpa_t root = vcpu->arch.mmu.pae_root[i];
|
|
|
|
ASSERT(!VALID_PAGE(root));
|
|
spin_lock(&vcpu->kvm->mmu_lock);
|
|
kvm_mmu_free_some_pages(vcpu);
|
|
sp = kvm_mmu_get_page(vcpu, i << (30 - PAGE_SHIFT),
|
|
i << 30,
|
|
PT32_ROOT_LEVEL, 1, ACC_ALL,
|
|
NULL);
|
|
root = __pa(sp->spt);
|
|
++sp->root_count;
|
|
spin_unlock(&vcpu->kvm->mmu_lock);
|
|
vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
|
|
}
|
|
vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
|
|
} else
|
|
BUG();
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
|
|
{
|
|
struct kvm_mmu_page *sp;
|
|
u64 pdptr, pm_mask;
|
|
gfn_t root_gfn;
|
|
int i;
|
|
|
|
root_gfn = vcpu->arch.mmu.get_cr3(vcpu) >> PAGE_SHIFT;
|
|
|
|
if (mmu_check_root(vcpu, root_gfn))
|
|
return 1;
|
|
|
|
/*
|
|
* Do we shadow a long mode page table? If so we need to
|
|
* write-protect the guests page table root.
|
|
*/
|
|
if (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL) {
|
|
hpa_t root = vcpu->arch.mmu.root_hpa;
|
|
|
|
ASSERT(!VALID_PAGE(root));
|
|
|
|
spin_lock(&vcpu->kvm->mmu_lock);
|
|
kvm_mmu_free_some_pages(vcpu);
|
|
sp = kvm_mmu_get_page(vcpu, root_gfn, 0, PT64_ROOT_LEVEL,
|
|
0, ACC_ALL, NULL);
|
|
root = __pa(sp->spt);
|
|
++sp->root_count;
|
|
spin_unlock(&vcpu->kvm->mmu_lock);
|
|
vcpu->arch.mmu.root_hpa = root;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* We shadow a 32 bit page table. This may be a legacy 2-level
|
|
* or a PAE 3-level page table. In either case we need to be aware that
|
|
* the shadow page table may be a PAE or a long mode page table.
|
|
*/
|
|
pm_mask = PT_PRESENT_MASK;
|
|
if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL)
|
|
pm_mask |= PT_ACCESSED_MASK | PT_WRITABLE_MASK | PT_USER_MASK;
|
|
|
|
for (i = 0; i < 4; ++i) {
|
|
hpa_t root = vcpu->arch.mmu.pae_root[i];
|
|
|
|
ASSERT(!VALID_PAGE(root));
|
|
if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
|
|
pdptr = vcpu->arch.mmu.get_pdptr(vcpu, i);
|
|
if (!is_present_gpte(pdptr)) {
|
|
vcpu->arch.mmu.pae_root[i] = 0;
|
|
continue;
|
|
}
|
|
root_gfn = pdptr >> PAGE_SHIFT;
|
|
if (mmu_check_root(vcpu, root_gfn))
|
|
return 1;
|
|
}
|
|
spin_lock(&vcpu->kvm->mmu_lock);
|
|
kvm_mmu_free_some_pages(vcpu);
|
|
sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
|
|
PT32_ROOT_LEVEL, 0,
|
|
ACC_ALL, NULL);
|
|
root = __pa(sp->spt);
|
|
++sp->root_count;
|
|
spin_unlock(&vcpu->kvm->mmu_lock);
|
|
|
|
vcpu->arch.mmu.pae_root[i] = root | pm_mask;
|
|
}
|
|
vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
|
|
|
|
/*
|
|
* If we shadow a 32 bit page table with a long mode page
|
|
* table we enter this path.
|
|
*/
|
|
if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
|
|
if (vcpu->arch.mmu.lm_root == NULL) {
|
|
/*
|
|
* The additional page necessary for this is only
|
|
* allocated on demand.
|
|
*/
|
|
|
|
u64 *lm_root;
|
|
|
|
lm_root = (void*)get_zeroed_page(GFP_KERNEL);
|
|
if (lm_root == NULL)
|
|
return 1;
|
|
|
|
lm_root[0] = __pa(vcpu->arch.mmu.pae_root) | pm_mask;
|
|
|
|
vcpu->arch.mmu.lm_root = lm_root;
|
|
}
|
|
|
|
vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.lm_root);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int mmu_alloc_roots(struct kvm_vcpu *vcpu)
|
|
{
|
|
if (vcpu->arch.mmu.direct_map)
|
|
return mmu_alloc_direct_roots(vcpu);
|
|
else
|
|
return mmu_alloc_shadow_roots(vcpu);
|
|
}
|
|
|
|
static void mmu_sync_roots(struct kvm_vcpu *vcpu)
|
|
{
|
|
int i;
|
|
struct kvm_mmu_page *sp;
|
|
|
|
if (vcpu->arch.mmu.direct_map)
|
|
return;
|
|
|
|
if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
|
|
return;
|
|
|
|
vcpu_clear_mmio_info(vcpu, ~0ul);
|
|
kvm_mmu_audit(vcpu, AUDIT_PRE_SYNC);
|
|
if (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL) {
|
|
hpa_t root = vcpu->arch.mmu.root_hpa;
|
|
sp = page_header(root);
|
|
mmu_sync_children(vcpu, sp);
|
|
kvm_mmu_audit(vcpu, AUDIT_POST_SYNC);
|
|
return;
|
|
}
|
|
for (i = 0; i < 4; ++i) {
|
|
hpa_t root = vcpu->arch.mmu.pae_root[i];
|
|
|
|
if (root && VALID_PAGE(root)) {
|
|
root &= PT64_BASE_ADDR_MASK;
|
|
sp = page_header(root);
|
|
mmu_sync_children(vcpu, sp);
|
|
}
|
|
}
|
|
kvm_mmu_audit(vcpu, AUDIT_POST_SYNC);
|
|
}
|
|
|
|
void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
|
|
{
|
|
spin_lock(&vcpu->kvm->mmu_lock);
|
|
mmu_sync_roots(vcpu);
|
|
spin_unlock(&vcpu->kvm->mmu_lock);
|
|
}
|
|
|
|
static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr,
|
|
u32 access, struct x86_exception *exception)
|
|
{
|
|
if (exception)
|
|
exception->error_code = 0;
|
|
return vaddr;
|
|
}
|
|
|
|
static gpa_t nonpaging_gva_to_gpa_nested(struct kvm_vcpu *vcpu, gva_t vaddr,
|
|
u32 access,
|
|
struct x86_exception *exception)
|
|
{
|
|
if (exception)
|
|
exception->error_code = 0;
|
|
return vcpu->arch.nested_mmu.translate_gpa(vcpu, vaddr, access);
|
|
}
|
|
|
|
static bool quickly_check_mmio_pf(struct kvm_vcpu *vcpu, u64 addr, bool direct)
|
|
{
|
|
if (direct)
|
|
return vcpu_match_mmio_gpa(vcpu, addr);
|
|
|
|
return vcpu_match_mmio_gva(vcpu, addr);
|
|
}
|
|
|
|
|
|
/*
|
|
* On direct hosts, the last spte is only allows two states
|
|
* for mmio page fault:
|
|
* - It is the mmio spte
|
|
* - It is zapped or it is being zapped.
|
|
*
|
|
* This function completely checks the spte when the last spte
|
|
* is not the mmio spte.
|
|
*/
|
|
static bool check_direct_spte_mmio_pf(u64 spte)
|
|
{
|
|
return __check_direct_spte_mmio_pf(spte);
|
|
}
|
|
|
|
static u64 walk_shadow_page_get_mmio_spte(struct kvm_vcpu *vcpu, u64 addr)
|
|
{
|
|
struct kvm_shadow_walk_iterator iterator;
|
|
u64 spte = 0ull;
|
|
|
|
walk_shadow_page_lockless_begin(vcpu);
|
|
for_each_shadow_entry_lockless(vcpu, addr, iterator, spte)
|
|
if (!is_shadow_present_pte(spte))
|
|
break;
|
|
walk_shadow_page_lockless_end(vcpu);
|
|
|
|
return spte;
|
|
}
|
|
|
|
/*
|
|
* If it is a real mmio page fault, return 1 and emulat the instruction
|
|
* directly, return 0 to let CPU fault again on the address, -1 is
|
|
* returned if bug is detected.
|
|
*/
|
|
int handle_mmio_page_fault_common(struct kvm_vcpu *vcpu, u64 addr, bool direct)
|
|
{
|
|
u64 spte;
|
|
|
|
if (quickly_check_mmio_pf(vcpu, addr, direct))
|
|
return 1;
|
|
|
|
spte = walk_shadow_page_get_mmio_spte(vcpu, addr);
|
|
|
|
if (is_mmio_spte(spte)) {
|
|
gfn_t gfn = get_mmio_spte_gfn(spte);
|
|
unsigned access = get_mmio_spte_access(spte);
|
|
|
|
if (direct)
|
|
addr = 0;
|
|
|
|
trace_handle_mmio_page_fault(addr, gfn, access);
|
|
vcpu_cache_mmio_info(vcpu, addr, gfn, access);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* It's ok if the gva is remapped by other cpus on shadow guest,
|
|
* it's a BUG if the gfn is not a mmio page.
|
|
*/
|
|
if (direct && !check_direct_spte_mmio_pf(spte))
|
|
return -1;
|
|
|
|
/*
|
|
* If the page table is zapped by other cpus, let CPU fault again on
|
|
* the address.
|
|
*/
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(handle_mmio_page_fault_common);
|
|
|
|
static int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr,
|
|
u32 error_code, bool direct)
|
|
{
|
|
int ret;
|
|
|
|
ret = handle_mmio_page_fault_common(vcpu, addr, direct);
|
|
WARN_ON(ret < 0);
|
|
return ret;
|
|
}
|
|
|
|
static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
|
|
u32 error_code, bool prefault)
|
|
{
|
|
gfn_t gfn;
|
|
int r;
|
|
|
|
pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code);
|
|
|
|
if (unlikely(error_code & PFERR_RSVD_MASK))
|
|
return handle_mmio_page_fault(vcpu, gva, error_code, true);
|
|
|
|
r = mmu_topup_memory_caches(vcpu);
|
|
if (r)
|
|
return r;
|
|
|
|
ASSERT(vcpu);
|
|
ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
|
|
|
|
gfn = gva >> PAGE_SHIFT;
|
|
|
|
return nonpaging_map(vcpu, gva & PAGE_MASK,
|
|
error_code & PFERR_WRITE_MASK, gfn, prefault);
|
|
}
|
|
|
|
static int kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn)
|
|
{
|
|
struct kvm_arch_async_pf arch;
|
|
|
|
arch.token = (vcpu->arch.apf.id++ << 12) | vcpu->vcpu_id;
|
|
arch.gfn = gfn;
|
|
arch.direct_map = vcpu->arch.mmu.direct_map;
|
|
arch.cr3 = vcpu->arch.mmu.get_cr3(vcpu);
|
|
|
|
return kvm_setup_async_pf(vcpu, gva, gfn, &arch);
|
|
}
|
|
|
|
static bool can_do_async_pf(struct kvm_vcpu *vcpu)
|
|
{
|
|
if (unlikely(!irqchip_in_kernel(vcpu->kvm) ||
|
|
kvm_event_needs_reinjection(vcpu)))
|
|
return false;
|
|
|
|
return kvm_x86_ops->interrupt_allowed(vcpu);
|
|
}
|
|
|
|
static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
|
|
gva_t gva, pfn_t *pfn, bool write, bool *writable)
|
|
{
|
|
bool async;
|
|
|
|
*pfn = gfn_to_pfn_async(vcpu->kvm, gfn, &async, write, writable);
|
|
|
|
if (!async)
|
|
return false; /* *pfn has correct page already */
|
|
|
|
put_page(pfn_to_page(*pfn));
|
|
|
|
if (!prefault && can_do_async_pf(vcpu)) {
|
|
trace_kvm_try_async_get_page(gva, gfn);
|
|
if (kvm_find_async_pf_gfn(vcpu, gfn)) {
|
|
trace_kvm_async_pf_doublefault(gva, gfn);
|
|
kvm_make_request(KVM_REQ_APF_HALT, vcpu);
|
|
return true;
|
|
} else if (kvm_arch_setup_async_pf(vcpu, gva, gfn))
|
|
return true;
|
|
}
|
|
|
|
*pfn = gfn_to_pfn_prot(vcpu->kvm, gfn, write, writable);
|
|
|
|
return false;
|
|
}
|
|
|
|
static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
|
|
bool prefault)
|
|
{
|
|
pfn_t pfn;
|
|
int r;
|
|
int level;
|
|
int force_pt_level;
|
|
gfn_t gfn = gpa >> PAGE_SHIFT;
|
|
unsigned long mmu_seq;
|
|
int write = error_code & PFERR_WRITE_MASK;
|
|
bool map_writable;
|
|
|
|
ASSERT(vcpu);
|
|
ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
|
|
|
|
if (unlikely(error_code & PFERR_RSVD_MASK))
|
|
return handle_mmio_page_fault(vcpu, gpa, error_code, true);
|
|
|
|
r = mmu_topup_memory_caches(vcpu);
|
|
if (r)
|
|
return r;
|
|
|
|
force_pt_level = mapping_level_dirty_bitmap(vcpu, gfn);
|
|
if (likely(!force_pt_level)) {
|
|
level = mapping_level(vcpu, gfn);
|
|
gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
|
|
} else
|
|
level = PT_PAGE_TABLE_LEVEL;
|
|
|
|
mmu_seq = vcpu->kvm->mmu_notifier_seq;
|
|
smp_rmb();
|
|
|
|
if (try_async_pf(vcpu, prefault, gfn, gpa, &pfn, write, &map_writable))
|
|
return 0;
|
|
|
|
if (handle_abnormal_pfn(vcpu, 0, gfn, pfn, ACC_ALL, &r))
|
|
return r;
|
|
|
|
spin_lock(&vcpu->kvm->mmu_lock);
|
|
if (mmu_notifier_retry(vcpu, mmu_seq))
|
|
goto out_unlock;
|
|
kvm_mmu_free_some_pages(vcpu);
|
|
if (likely(!force_pt_level))
|
|
transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
|
|
r = __direct_map(vcpu, gpa, write, map_writable,
|
|
level, gfn, pfn, prefault);
|
|
spin_unlock(&vcpu->kvm->mmu_lock);
|
|
|
|
return r;
|
|
|
|
out_unlock:
|
|
spin_unlock(&vcpu->kvm->mmu_lock);
|
|
kvm_release_pfn_clean(pfn);
|
|
return 0;
|
|
}
|
|
|
|
static void nonpaging_free(struct kvm_vcpu *vcpu)
|
|
{
|
|
mmu_free_roots(vcpu);
|
|
}
|
|
|
|
static int nonpaging_init_context(struct kvm_vcpu *vcpu,
|
|
struct kvm_mmu *context)
|
|
{
|
|
context->new_cr3 = nonpaging_new_cr3;
|
|
context->page_fault = nonpaging_page_fault;
|
|
context->gva_to_gpa = nonpaging_gva_to_gpa;
|
|
context->free = nonpaging_free;
|
|
context->sync_page = nonpaging_sync_page;
|
|
context->invlpg = nonpaging_invlpg;
|
|
context->update_pte = nonpaging_update_pte;
|
|
context->root_level = 0;
|
|
context->shadow_root_level = PT32E_ROOT_LEVEL;
|
|
context->root_hpa = INVALID_PAGE;
|
|
context->direct_map = true;
|
|
context->nx = false;
|
|
return 0;
|
|
}
|
|
|
|
void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
|
|
{
|
|
++vcpu->stat.tlb_flush;
|
|
kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
|
|
}
|
|
|
|
static void paging_new_cr3(struct kvm_vcpu *vcpu)
|
|
{
|
|
pgprintk("%s: cr3 %lx\n", __func__, kvm_read_cr3(vcpu));
|
|
mmu_free_roots(vcpu);
|
|
}
|
|
|
|
static unsigned long get_cr3(struct kvm_vcpu *vcpu)
|
|
{
|
|
return kvm_read_cr3(vcpu);
|
|
}
|
|
|
|
static void inject_page_fault(struct kvm_vcpu *vcpu,
|
|
struct x86_exception *fault)
|
|
{
|
|
vcpu->arch.mmu.inject_page_fault(vcpu, fault);
|
|
}
|
|
|
|
static void paging_free(struct kvm_vcpu *vcpu)
|
|
{
|
|
nonpaging_free(vcpu);
|
|
}
|
|
|
|
static bool is_rsvd_bits_set(struct kvm_mmu *mmu, u64 gpte, int level)
|
|
{
|
|
int bit7;
|
|
|
|
bit7 = (gpte >> 7) & 1;
|
|
return (gpte & mmu->rsvd_bits_mask[bit7][level-1]) != 0;
|
|
}
|
|
|
|
static bool sync_mmio_spte(u64 *sptep, gfn_t gfn, unsigned access,
|
|
int *nr_present)
|
|
{
|
|
if (unlikely(is_mmio_spte(*sptep))) {
|
|
if (gfn != get_mmio_spte_gfn(*sptep)) {
|
|
mmu_spte_clear_no_track(sptep);
|
|
return true;
|
|
}
|
|
|
|
(*nr_present)++;
|
|
mark_mmio_spte(sptep, gfn, access);
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
#define PTTYPE 64
|
|
#include "paging_tmpl.h"
|
|
#undef PTTYPE
|
|
|
|
#define PTTYPE 32
|
|
#include "paging_tmpl.h"
|
|
#undef PTTYPE
|
|
|
|
static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu,
|
|
struct kvm_mmu *context)
|
|
{
|
|
int maxphyaddr = cpuid_maxphyaddr(vcpu);
|
|
u64 exb_bit_rsvd = 0;
|
|
|
|
if (!context->nx)
|
|
exb_bit_rsvd = rsvd_bits(63, 63);
|
|
switch (context->root_level) {
|
|
case PT32_ROOT_LEVEL:
|
|
/* no rsvd bits for 2 level 4K page table entries */
|
|
context->rsvd_bits_mask[0][1] = 0;
|
|
context->rsvd_bits_mask[0][0] = 0;
|
|
context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
|
|
|
|
if (!is_pse(vcpu)) {
|
|
context->rsvd_bits_mask[1][1] = 0;
|
|
break;
|
|
}
|
|
|
|
if (is_cpuid_PSE36())
|
|
/* 36bits PSE 4MB page */
|
|
context->rsvd_bits_mask[1][1] = rsvd_bits(17, 21);
|
|
else
|
|
/* 32 bits PSE 4MB page */
|
|
context->rsvd_bits_mask[1][1] = rsvd_bits(13, 21);
|
|
break;
|
|
case PT32E_ROOT_LEVEL:
|
|
context->rsvd_bits_mask[0][2] =
|
|
rsvd_bits(maxphyaddr, 63) |
|
|
rsvd_bits(7, 8) | rsvd_bits(1, 2); /* PDPTE */
|
|
context->rsvd_bits_mask[0][1] = exb_bit_rsvd |
|
|
rsvd_bits(maxphyaddr, 62); /* PDE */
|
|
context->rsvd_bits_mask[0][0] = exb_bit_rsvd |
|
|
rsvd_bits(maxphyaddr, 62); /* PTE */
|
|
context->rsvd_bits_mask[1][1] = exb_bit_rsvd |
|
|
rsvd_bits(maxphyaddr, 62) |
|
|
rsvd_bits(13, 20); /* large page */
|
|
context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
|
|
break;
|
|
case PT64_ROOT_LEVEL:
|
|
context->rsvd_bits_mask[0][3] = exb_bit_rsvd |
|
|
rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8);
|
|
context->rsvd_bits_mask[0][2] = exb_bit_rsvd |
|
|
rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8);
|
|
context->rsvd_bits_mask[0][1] = exb_bit_rsvd |
|
|
rsvd_bits(maxphyaddr, 51);
|
|
context->rsvd_bits_mask[0][0] = exb_bit_rsvd |
|
|
rsvd_bits(maxphyaddr, 51);
|
|
context->rsvd_bits_mask[1][3] = context->rsvd_bits_mask[0][3];
|
|
context->rsvd_bits_mask[1][2] = exb_bit_rsvd |
|
|
rsvd_bits(maxphyaddr, 51) |
|
|
rsvd_bits(13, 29);
|
|
context->rsvd_bits_mask[1][1] = exb_bit_rsvd |
|
|
rsvd_bits(maxphyaddr, 51) |
|
|
rsvd_bits(13, 20); /* large page */
|
|
context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
|
|
break;
|
|
}
|
|
}
|
|
|
|
static int paging64_init_context_common(struct kvm_vcpu *vcpu,
|
|
struct kvm_mmu *context,
|
|
int level)
|
|
{
|
|
context->nx = is_nx(vcpu);
|
|
context->root_level = level;
|
|
|
|
reset_rsvds_bits_mask(vcpu, context);
|
|
|
|
ASSERT(is_pae(vcpu));
|
|
context->new_cr3 = paging_new_cr3;
|
|
context->page_fault = paging64_page_fault;
|
|
context->gva_to_gpa = paging64_gva_to_gpa;
|
|
context->sync_page = paging64_sync_page;
|
|
context->invlpg = paging64_invlpg;
|
|
context->update_pte = paging64_update_pte;
|
|
context->free = paging_free;
|
|
context->shadow_root_level = level;
|
|
context->root_hpa = INVALID_PAGE;
|
|
context->direct_map = false;
|
|
return 0;
|
|
}
|
|
|
|
static int paging64_init_context(struct kvm_vcpu *vcpu,
|
|
struct kvm_mmu *context)
|
|
{
|
|
return paging64_init_context_common(vcpu, context, PT64_ROOT_LEVEL);
|
|
}
|
|
|
|
static int paging32_init_context(struct kvm_vcpu *vcpu,
|
|
struct kvm_mmu *context)
|
|
{
|
|
context->nx = false;
|
|
context->root_level = PT32_ROOT_LEVEL;
|
|
|
|
reset_rsvds_bits_mask(vcpu, context);
|
|
|
|
context->new_cr3 = paging_new_cr3;
|
|
context->page_fault = paging32_page_fault;
|
|
context->gva_to_gpa = paging32_gva_to_gpa;
|
|
context->free = paging_free;
|
|
context->sync_page = paging32_sync_page;
|
|
context->invlpg = paging32_invlpg;
|
|
context->update_pte = paging32_update_pte;
|
|
context->shadow_root_level = PT32E_ROOT_LEVEL;
|
|
context->root_hpa = INVALID_PAGE;
|
|
context->direct_map = false;
|
|
return 0;
|
|
}
|
|
|
|
static int paging32E_init_context(struct kvm_vcpu *vcpu,
|
|
struct kvm_mmu *context)
|
|
{
|
|
return paging64_init_context_common(vcpu, context, PT32E_ROOT_LEVEL);
|
|
}
|
|
|
|
static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
|
|
{
|
|
struct kvm_mmu *context = vcpu->arch.walk_mmu;
|
|
|
|
context->base_role.word = 0;
|
|
context->new_cr3 = nonpaging_new_cr3;
|
|
context->page_fault = tdp_page_fault;
|
|
context->free = nonpaging_free;
|
|
context->sync_page = nonpaging_sync_page;
|
|
context->invlpg = nonpaging_invlpg;
|
|
context->update_pte = nonpaging_update_pte;
|
|
context->shadow_root_level = kvm_x86_ops->get_tdp_level();
|
|
context->root_hpa = INVALID_PAGE;
|
|
context->direct_map = true;
|
|
context->set_cr3 = kvm_x86_ops->set_tdp_cr3;
|
|
context->get_cr3 = get_cr3;
|
|
context->get_pdptr = kvm_pdptr_read;
|
|
context->inject_page_fault = kvm_inject_page_fault;
|
|
|
|
if (!is_paging(vcpu)) {
|
|
context->nx = false;
|
|
context->gva_to_gpa = nonpaging_gva_to_gpa;
|
|
context->root_level = 0;
|
|
} else if (is_long_mode(vcpu)) {
|
|
context->nx = is_nx(vcpu);
|
|
context->root_level = PT64_ROOT_LEVEL;
|
|
reset_rsvds_bits_mask(vcpu, context);
|
|
context->gva_to_gpa = paging64_gva_to_gpa;
|
|
} else if (is_pae(vcpu)) {
|
|
context->nx = is_nx(vcpu);
|
|
context->root_level = PT32E_ROOT_LEVEL;
|
|
reset_rsvds_bits_mask(vcpu, context);
|
|
context->gva_to_gpa = paging64_gva_to_gpa;
|
|
} else {
|
|
context->nx = false;
|
|
context->root_level = PT32_ROOT_LEVEL;
|
|
reset_rsvds_bits_mask(vcpu, context);
|
|
context->gva_to_gpa = paging32_gva_to_gpa;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context)
|
|
{
|
|
int r;
|
|
bool smep = kvm_read_cr4_bits(vcpu, X86_CR4_SMEP);
|
|
ASSERT(vcpu);
|
|
ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
|
|
|
|
if (!is_paging(vcpu))
|
|
r = nonpaging_init_context(vcpu, context);
|
|
else if (is_long_mode(vcpu))
|
|
r = paging64_init_context(vcpu, context);
|
|
else if (is_pae(vcpu))
|
|
r = paging32E_init_context(vcpu, context);
|
|
else
|
|
r = paging32_init_context(vcpu, context);
|
|
|
|
vcpu->arch.mmu.base_role.cr4_pae = !!is_pae(vcpu);
|
|
vcpu->arch.mmu.base_role.cr0_wp = is_write_protection(vcpu);
|
|
vcpu->arch.mmu.base_role.smep_andnot_wp
|
|
= smep && !is_write_protection(vcpu);
|
|
|
|
return r;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kvm_init_shadow_mmu);
|
|
|
|
static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
|
|
{
|
|
int r = kvm_init_shadow_mmu(vcpu, vcpu->arch.walk_mmu);
|
|
|
|
vcpu->arch.walk_mmu->set_cr3 = kvm_x86_ops->set_cr3;
|
|
vcpu->arch.walk_mmu->get_cr3 = get_cr3;
|
|
vcpu->arch.walk_mmu->get_pdptr = kvm_pdptr_read;
|
|
vcpu->arch.walk_mmu->inject_page_fault = kvm_inject_page_fault;
|
|
|
|
return r;
|
|
}
|
|
|
|
static int init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
|
|
{
|
|
struct kvm_mmu *g_context = &vcpu->arch.nested_mmu;
|
|
|
|
g_context->get_cr3 = get_cr3;
|
|
g_context->get_pdptr = kvm_pdptr_read;
|
|
g_context->inject_page_fault = kvm_inject_page_fault;
|
|
|
|
/*
|
|
* Note that arch.mmu.gva_to_gpa translates l2_gva to l1_gpa. The
|
|
* translation of l2_gpa to l1_gpa addresses is done using the
|
|
* arch.nested_mmu.gva_to_gpa function. Basically the gva_to_gpa
|
|
* functions between mmu and nested_mmu are swapped.
|
|
*/
|
|
if (!is_paging(vcpu)) {
|
|
g_context->nx = false;
|
|
g_context->root_level = 0;
|
|
g_context->gva_to_gpa = nonpaging_gva_to_gpa_nested;
|
|
} else if (is_long_mode(vcpu)) {
|
|
g_context->nx = is_nx(vcpu);
|
|
g_context->root_level = PT64_ROOT_LEVEL;
|
|
reset_rsvds_bits_mask(vcpu, g_context);
|
|
g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
|
|
} else if (is_pae(vcpu)) {
|
|
g_context->nx = is_nx(vcpu);
|
|
g_context->root_level = PT32E_ROOT_LEVEL;
|
|
reset_rsvds_bits_mask(vcpu, g_context);
|
|
g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
|
|
} else {
|
|
g_context->nx = false;
|
|
g_context->root_level = PT32_ROOT_LEVEL;
|
|
reset_rsvds_bits_mask(vcpu, g_context);
|
|
g_context->gva_to_gpa = paging32_gva_to_gpa_nested;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int init_kvm_mmu(struct kvm_vcpu *vcpu)
|
|
{
|
|
if (mmu_is_nested(vcpu))
|
|
return init_kvm_nested_mmu(vcpu);
|
|
else if (tdp_enabled)
|
|
return init_kvm_tdp_mmu(vcpu);
|
|
else
|
|
return init_kvm_softmmu(vcpu);
|
|
}
|
|
|
|
static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
|
|
{
|
|
ASSERT(vcpu);
|
|
if (VALID_PAGE(vcpu->arch.mmu.root_hpa))
|
|
/* mmu.free() should set root_hpa = INVALID_PAGE */
|
|
vcpu->arch.mmu.free(vcpu);
|
|
}
|
|
|
|
int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
|
|
{
|
|
destroy_kvm_mmu(vcpu);
|
|
return init_kvm_mmu(vcpu);
|
|
}
|
|
EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
|
|
|
|
int kvm_mmu_load(struct kvm_vcpu *vcpu)
|
|
{
|
|
int r;
|
|
|
|
r = mmu_topup_memory_caches(vcpu);
|
|
if (r)
|
|
goto out;
|
|
r = mmu_alloc_roots(vcpu);
|
|
spin_lock(&vcpu->kvm->mmu_lock);
|
|
mmu_sync_roots(vcpu);
|
|
spin_unlock(&vcpu->kvm->mmu_lock);
|
|
if (r)
|
|
goto out;
|
|
/* set_cr3() should ensure TLB has been flushed */
|
|
vcpu->arch.mmu.set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
|
|
out:
|
|
return r;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kvm_mmu_load);
|
|
|
|
void kvm_mmu_unload(struct kvm_vcpu *vcpu)
|
|
{
|
|
mmu_free_roots(vcpu);
|
|
}
|
|
EXPORT_SYMBOL_GPL(kvm_mmu_unload);
|
|
|
|
static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
|
|
struct kvm_mmu_page *sp, u64 *spte,
|
|
const void *new)
|
|
{
|
|
if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
|
|
++vcpu->kvm->stat.mmu_pde_zapped;
|
|
return;
|
|
}
|
|
|
|
++vcpu->kvm->stat.mmu_pte_updated;
|
|
vcpu->arch.mmu.update_pte(vcpu, sp, spte, new);
|
|
}
|
|
|
|
static bool need_remote_flush(u64 old, u64 new)
|
|
{
|
|
if (!is_shadow_present_pte(old))
|
|
return false;
|
|
if (!is_shadow_present_pte(new))
|
|
return true;
|
|
if ((old ^ new) & PT64_BASE_ADDR_MASK)
|
|
return true;
|
|
old ^= PT64_NX_MASK;
|
|
new ^= PT64_NX_MASK;
|
|
return (old & ~new & PT64_PERM_MASK) != 0;
|
|
}
|
|
|
|
static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, bool zap_page,
|
|
bool remote_flush, bool local_flush)
|
|
{
|
|
if (zap_page)
|
|
return;
|
|
|
|
if (remote_flush)
|
|
kvm_flush_remote_tlbs(vcpu->kvm);
|
|
else if (local_flush)
|
|
kvm_mmu_flush_tlb(vcpu);
|
|
}
|
|
|
|
static u64 mmu_pte_write_fetch_gpte(struct kvm_vcpu *vcpu, gpa_t *gpa,
|
|
const u8 *new, int *bytes)
|
|
{
|
|
u64 gentry;
|
|
int r;
|
|
|
|
/*
|
|
* Assume that the pte write on a page table of the same type
|
|
* as the current vcpu paging mode since we update the sptes only
|
|
* when they have the same mode.
|
|
*/
|
|
if (is_pae(vcpu) && *bytes == 4) {
|
|
/* Handle a 32-bit guest writing two halves of a 64-bit gpte */
|
|
*gpa &= ~(gpa_t)7;
|
|
*bytes = 8;
|
|
r = kvm_read_guest(vcpu->kvm, *gpa, &gentry, min(*bytes, 8));
|
|
if (r)
|
|
gentry = 0;
|
|
new = (const u8 *)&gentry;
|
|
}
|
|
|
|
switch (*bytes) {
|
|
case 4:
|
|
gentry = *(const u32 *)new;
|
|
break;
|
|
case 8:
|
|
gentry = *(const u64 *)new;
|
|
break;
|
|
default:
|
|
gentry = 0;
|
|
break;
|
|
}
|
|
|
|
return gentry;
|
|
}
|
|
|
|
/*
|
|
* If we're seeing too many writes to a page, it may no longer be a page table,
|
|
* or we may be forking, in which case it is better to unmap the page.
|
|
*/
|
|
static bool detect_write_flooding(struct kvm_mmu_page *sp)
|
|
{
|
|
/*
|
|
* Skip write-flooding detected for the sp whose level is 1, because
|
|
* it can become unsync, then the guest page is not write-protected.
|
|
*/
|
|
if (sp->role.level == 1)
|
|
return false;
|
|
|
|
return ++sp->write_flooding_count >= 3;
|
|
}
|
|
|
|
/*
|
|
* Misaligned accesses are too much trouble to fix up; also, they usually
|
|
* indicate a page is not used as a page table.
|
|
*/
|
|
static bool detect_write_misaligned(struct kvm_mmu_page *sp, gpa_t gpa,
|
|
int bytes)
|
|
{
|
|
unsigned offset, pte_size, misaligned;
|
|
|
|
pgprintk("misaligned: gpa %llx bytes %d role %x\n",
|
|
gpa, bytes, sp->role.word);
|
|
|
|
offset = offset_in_page(gpa);
|
|
pte_size = sp->role.cr4_pae ? 8 : 4;
|
|
|
|
/*
|
|
* Sometimes, the OS only writes the last one bytes to update status
|
|
* bits, for example, in linux, andb instruction is used in clear_bit().
|
|
*/
|
|
if (!(offset & (pte_size - 1)) && bytes == 1)
|
|
return false;
|
|
|
|
misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
|
|
misaligned |= bytes < 4;
|
|
|
|
return misaligned;
|
|
}
|
|
|
|
static u64 *get_written_sptes(struct kvm_mmu_page *sp, gpa_t gpa, int *nspte)
|
|
{
|
|
unsigned page_offset, quadrant;
|
|
u64 *spte;
|
|
int level;
|
|
|
|
page_offset = offset_in_page(gpa);
|
|
level = sp->role.level;
|
|
*nspte = 1;
|
|
if (!sp->role.cr4_pae) {
|
|
page_offset <<= 1; /* 32->64 */
|
|
/*
|
|
* A 32-bit pde maps 4MB while the shadow pdes map
|
|
* only 2MB. So we need to double the offset again
|
|
* and zap two pdes instead of one.
|
|
*/
|
|
if (level == PT32_ROOT_LEVEL) {
|
|
page_offset &= ~7; /* kill rounding error */
|
|
page_offset <<= 1;
|
|
*nspte = 2;
|
|
}
|
|
quadrant = page_offset >> PAGE_SHIFT;
|
|
page_offset &= ~PAGE_MASK;
|
|
if (quadrant != sp->role.quadrant)
|
|
return NULL;
|
|
}
|
|
|
|
spte = &sp->spt[page_offset / sizeof(*spte)];
|
|
return spte;
|
|
}
|
|
|
|
void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
|
|
const u8 *new, int bytes)
|
|
{
|
|
gfn_t gfn = gpa >> PAGE_SHIFT;
|
|
union kvm_mmu_page_role mask = { .word = 0 };
|
|
struct kvm_mmu_page *sp;
|
|
struct hlist_node *node;
|
|
LIST_HEAD(invalid_list);
|
|
u64 entry, gentry, *spte;
|
|
int npte;
|
|
bool remote_flush, local_flush, zap_page;
|
|
|
|
/*
|
|
* If we don't have indirect shadow pages, it means no page is
|
|
* write-protected, so we can exit simply.
|
|
*/
|
|
if (!ACCESS_ONCE(vcpu->kvm->arch.indirect_shadow_pages))
|
|
return;
|
|
|
|
zap_page = remote_flush = local_flush = false;
|
|
|
|
pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);
|
|
|
|
gentry = mmu_pte_write_fetch_gpte(vcpu, &gpa, new, &bytes);
|
|
|
|
/*
|
|
* No need to care whether allocation memory is successful
|
|
* or not since pte prefetch is skiped if it does not have
|
|
* enough objects in the cache.
|
|
*/
|
|
mmu_topup_memory_caches(vcpu);
|
|
|
|
spin_lock(&vcpu->kvm->mmu_lock);
|
|
++vcpu->kvm->stat.mmu_pte_write;
|
|
kvm_mmu_audit(vcpu, AUDIT_PRE_PTE_WRITE);
|
|
|
|
mask.cr0_wp = mask.cr4_pae = mask.nxe = 1;
|
|
for_each_gfn_indirect_valid_sp(vcpu->kvm, sp, gfn, node) {
|
|
if (detect_write_misaligned(sp, gpa, bytes) ||
|
|
detect_write_flooding(sp)) {
|
|
zap_page |= !!kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
|
|
&invalid_list);
|
|
++vcpu->kvm->stat.mmu_flooded;
|
|
continue;
|
|
}
|
|
|
|
spte = get_written_sptes(sp, gpa, &npte);
|
|
if (!spte)
|
|
continue;
|
|
|
|
local_flush = true;
|
|
while (npte--) {
|
|
entry = *spte;
|
|
mmu_page_zap_pte(vcpu->kvm, sp, spte);
|
|
if (gentry &&
|
|
!((sp->role.word ^ vcpu->arch.mmu.base_role.word)
|
|
& mask.word) && rmap_can_add(vcpu))
|
|
mmu_pte_write_new_pte(vcpu, sp, spte, &gentry);
|
|
if (!remote_flush && need_remote_flush(entry, *spte))
|
|
remote_flush = true;
|
|
++spte;
|
|
}
|
|
}
|
|
mmu_pte_write_flush_tlb(vcpu, zap_page, remote_flush, local_flush);
|
|
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
|
|
kvm_mmu_audit(vcpu, AUDIT_POST_PTE_WRITE);
|
|
spin_unlock(&vcpu->kvm->mmu_lock);
|
|
}
|
|
|
|
int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
|
|
{
|
|
gpa_t gpa;
|
|
int r;
|
|
|
|
if (vcpu->arch.mmu.direct_map)
|
|
return 0;
|
|
|
|
gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL);
|
|
|
|
r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
|
|
|
|
return r;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt);
|
|
|
|
void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
|
|
{
|
|
LIST_HEAD(invalid_list);
|
|
|
|
while (kvm_mmu_available_pages(vcpu->kvm) < KVM_REFILL_PAGES &&
|
|
!list_empty(&vcpu->kvm->arch.active_mmu_pages)) {
|
|
struct kvm_mmu_page *sp;
|
|
|
|
sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
|
|
struct kvm_mmu_page, link);
|
|
kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list);
|
|
++vcpu->kvm->stat.mmu_recycled;
|
|
}
|
|
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
|
|
}
|
|
|
|
static bool is_mmio_page_fault(struct kvm_vcpu *vcpu, gva_t addr)
|
|
{
|
|
if (vcpu->arch.mmu.direct_map || mmu_is_nested(vcpu))
|
|
return vcpu_match_mmio_gpa(vcpu, addr);
|
|
|
|
return vcpu_match_mmio_gva(vcpu, addr);
|
|
}
|
|
|
|
int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code,
|
|
void *insn, int insn_len)
|
|
{
|
|
int r, emulation_type = EMULTYPE_RETRY;
|
|
enum emulation_result er;
|
|
|
|
r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code, false);
|
|
if (r < 0)
|
|
goto out;
|
|
|
|
if (!r) {
|
|
r = 1;
|
|
goto out;
|
|
}
|
|
|
|
if (is_mmio_page_fault(vcpu, cr2))
|
|
emulation_type = 0;
|
|
|
|
er = x86_emulate_instruction(vcpu, cr2, emulation_type, insn, insn_len);
|
|
|
|
switch (er) {
|
|
case EMULATE_DONE:
|
|
return 1;
|
|
case EMULATE_DO_MMIO:
|
|
++vcpu->stat.mmio_exits;
|
|
/* fall through */
|
|
case EMULATE_FAIL:
|
|
return 0;
|
|
default:
|
|
BUG();
|
|
}
|
|
out:
|
|
return r;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
|
|
|
|
void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
|
|
{
|
|
vcpu->arch.mmu.invlpg(vcpu, gva);
|
|
kvm_mmu_flush_tlb(vcpu);
|
|
++vcpu->stat.invlpg;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kvm_mmu_invlpg);
|
|
|
|
void kvm_enable_tdp(void)
|
|
{
|
|
tdp_enabled = true;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kvm_enable_tdp);
|
|
|
|
void kvm_disable_tdp(void)
|
|
{
|
|
tdp_enabled = false;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kvm_disable_tdp);
|
|
|
|
static void free_mmu_pages(struct kvm_vcpu *vcpu)
|
|
{
|
|
free_page((unsigned long)vcpu->arch.mmu.pae_root);
|
|
if (vcpu->arch.mmu.lm_root != NULL)
|
|
free_page((unsigned long)vcpu->arch.mmu.lm_root);
|
|
}
|
|
|
|
static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
|
|
{
|
|
struct page *page;
|
|
int i;
|
|
|
|
ASSERT(vcpu);
|
|
|
|
/*
|
|
* When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
|
|
* Therefore we need to allocate shadow page tables in the first
|
|
* 4GB of memory, which happens to fit the DMA32 zone.
|
|
*/
|
|
page = alloc_page(GFP_KERNEL | __GFP_DMA32);
|
|
if (!page)
|
|
return -ENOMEM;
|
|
|
|
vcpu->arch.mmu.pae_root = page_address(page);
|
|
for (i = 0; i < 4; ++i)
|
|
vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int kvm_mmu_create(struct kvm_vcpu *vcpu)
|
|
{
|
|
ASSERT(vcpu);
|
|
|
|
vcpu->arch.walk_mmu = &vcpu->arch.mmu;
|
|
vcpu->arch.mmu.root_hpa = INVALID_PAGE;
|
|
vcpu->arch.mmu.translate_gpa = translate_gpa;
|
|
vcpu->arch.nested_mmu.translate_gpa = translate_nested_gpa;
|
|
|
|
return alloc_mmu_pages(vcpu);
|
|
}
|
|
|
|
int kvm_mmu_setup(struct kvm_vcpu *vcpu)
|
|
{
|
|
ASSERT(vcpu);
|
|
ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
|
|
|
|
return init_kvm_mmu(vcpu);
|
|
}
|
|
|
|
void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
|
|
{
|
|
struct kvm_mmu_page *sp;
|
|
|
|
list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) {
|
|
int i;
|
|
u64 *pt;
|
|
|
|
if (!test_bit(slot, sp->slot_bitmap))
|
|
continue;
|
|
|
|
pt = sp->spt;
|
|
for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
|
|
if (!is_shadow_present_pte(pt[i]) ||
|
|
!is_last_spte(pt[i], sp->role.level))
|
|
continue;
|
|
|
|
if (is_large_pte(pt[i])) {
|
|
drop_spte(kvm, &pt[i]);
|
|
--kvm->stat.lpages;
|
|
continue;
|
|
}
|
|
|
|
/* avoid RMW */
|
|
if (is_writable_pte(pt[i]))
|
|
mmu_spte_update(&pt[i],
|
|
pt[i] & ~PT_WRITABLE_MASK);
|
|
}
|
|
}
|
|
kvm_flush_remote_tlbs(kvm);
|
|
}
|
|
|
|
void kvm_mmu_zap_all(struct kvm *kvm)
|
|
{
|
|
struct kvm_mmu_page *sp, *node;
|
|
LIST_HEAD(invalid_list);
|
|
|
|
spin_lock(&kvm->mmu_lock);
|
|
restart:
|
|
list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link)
|
|
if (kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list))
|
|
goto restart;
|
|
|
|
kvm_mmu_commit_zap_page(kvm, &invalid_list);
|
|
spin_unlock(&kvm->mmu_lock);
|
|
}
|
|
|
|
static void kvm_mmu_remove_some_alloc_mmu_pages(struct kvm *kvm,
|
|
struct list_head *invalid_list)
|
|
{
|
|
struct kvm_mmu_page *page;
|
|
|
|
page = container_of(kvm->arch.active_mmu_pages.prev,
|
|
struct kvm_mmu_page, link);
|
|
kvm_mmu_prepare_zap_page(kvm, page, invalid_list);
|
|
}
|
|
|
|
static int mmu_shrink(struct shrinker *shrink, struct shrink_control *sc)
|
|
{
|
|
struct kvm *kvm;
|
|
struct kvm *kvm_freed = NULL;
|
|
int nr_to_scan = sc->nr_to_scan;
|
|
|
|
if (nr_to_scan == 0)
|
|
goto out;
|
|
|
|
raw_spin_lock(&kvm_lock);
|
|
|
|
list_for_each_entry(kvm, &vm_list, vm_list) {
|
|
int idx;
|
|
LIST_HEAD(invalid_list);
|
|
|
|
idx = srcu_read_lock(&kvm->srcu);
|
|
spin_lock(&kvm->mmu_lock);
|
|
if (!kvm_freed && nr_to_scan > 0 &&
|
|
kvm->arch.n_used_mmu_pages > 0) {
|
|
kvm_mmu_remove_some_alloc_mmu_pages(kvm,
|
|
&invalid_list);
|
|
kvm_freed = kvm;
|
|
}
|
|
nr_to_scan--;
|
|
|
|
kvm_mmu_commit_zap_page(kvm, &invalid_list);
|
|
spin_unlock(&kvm->mmu_lock);
|
|
srcu_read_unlock(&kvm->srcu, idx);
|
|
}
|
|
if (kvm_freed)
|
|
list_move_tail(&kvm_freed->vm_list, &vm_list);
|
|
|
|
raw_spin_unlock(&kvm_lock);
|
|
|
|
out:
|
|
return percpu_counter_read_positive(&kvm_total_used_mmu_pages);
|
|
}
|
|
|
|
static struct shrinker mmu_shrinker = {
|
|
.shrink = mmu_shrink,
|
|
.seeks = DEFAULT_SEEKS * 10,
|
|
};
|
|
|
|
static void mmu_destroy_caches(void)
|
|
{
|
|
if (pte_list_desc_cache)
|
|
kmem_cache_destroy(pte_list_desc_cache);
|
|
if (mmu_page_header_cache)
|
|
kmem_cache_destroy(mmu_page_header_cache);
|
|
}
|
|
|
|
int kvm_mmu_module_init(void)
|
|
{
|
|
pte_list_desc_cache = kmem_cache_create("pte_list_desc",
|
|
sizeof(struct pte_list_desc),
|
|
0, 0, NULL);
|
|
if (!pte_list_desc_cache)
|
|
goto nomem;
|
|
|
|
mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
|
|
sizeof(struct kvm_mmu_page),
|
|
0, 0, NULL);
|
|
if (!mmu_page_header_cache)
|
|
goto nomem;
|
|
|
|
if (percpu_counter_init(&kvm_total_used_mmu_pages, 0))
|
|
goto nomem;
|
|
|
|
register_shrinker(&mmu_shrinker);
|
|
|
|
return 0;
|
|
|
|
nomem:
|
|
mmu_destroy_caches();
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* Caculate mmu pages needed for kvm.
|
|
*/
|
|
unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
|
|
{
|
|
unsigned int nr_mmu_pages;
|
|
unsigned int nr_pages = 0;
|
|
struct kvm_memslots *slots;
|
|
struct kvm_memory_slot *memslot;
|
|
|
|
slots = kvm_memslots(kvm);
|
|
|
|
kvm_for_each_memslot(memslot, slots)
|
|
nr_pages += memslot->npages;
|
|
|
|
nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
|
|
nr_mmu_pages = max(nr_mmu_pages,
|
|
(unsigned int) KVM_MIN_ALLOC_MMU_PAGES);
|
|
|
|
return nr_mmu_pages;
|
|
}
|
|
|
|
int kvm_mmu_get_spte_hierarchy(struct kvm_vcpu *vcpu, u64 addr, u64 sptes[4])
|
|
{
|
|
struct kvm_shadow_walk_iterator iterator;
|
|
u64 spte;
|
|
int nr_sptes = 0;
|
|
|
|
walk_shadow_page_lockless_begin(vcpu);
|
|
for_each_shadow_entry_lockless(vcpu, addr, iterator, spte) {
|
|
sptes[iterator.level-1] = spte;
|
|
nr_sptes++;
|
|
if (!is_shadow_present_pte(spte))
|
|
break;
|
|
}
|
|
walk_shadow_page_lockless_end(vcpu);
|
|
|
|
return nr_sptes;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kvm_mmu_get_spte_hierarchy);
|
|
|
|
void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
|
|
{
|
|
ASSERT(vcpu);
|
|
|
|
destroy_kvm_mmu(vcpu);
|
|
free_mmu_pages(vcpu);
|
|
mmu_free_memory_caches(vcpu);
|
|
}
|
|
|
|
void kvm_mmu_module_exit(void)
|
|
{
|
|
mmu_destroy_caches();
|
|
percpu_counter_destroy(&kvm_total_used_mmu_pages);
|
|
unregister_shrinker(&mmu_shrinker);
|
|
mmu_audit_disable();
|
|
}
|