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linux-pinenote/arch/powerpc/kvm/emulate.c
Alexander Graf 54771e6217 KVM: PPC: Emulator: clean up SPR reads and writes 
When reading and writing SPRs, every SPR emulation piece had to read
or write the respective GPR the value was read from or stored in itself.

This approach is pretty prone to failure. What if we accidentally
implement mfspr emulation where we just do "break" and nothing else?
Suddenly we would get a random value in the return register - which is
always a bad idea.

So let's consolidate the generic code paths and only give the core
specific SPR handling code readily made variables to read/write from/to.

Functionally, this patch doesn't change anything, but it increases the
readability of the code and makes is less prone to bugs.

Signed-off-by: Alexander Graf <agraf@suse.de>
2012-05-06 16:19:13 +02:00

489 lines
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/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* Copyright IBM Corp. 2007
* Copyright 2011 Freescale Semiconductor, Inc.
*
* Authors: Hollis Blanchard <hollisb@us.ibm.com>
*/
#include <linux/jiffies.h>
#include <linux/hrtimer.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kvm_host.h>
#include <linux/clockchips.h>
#include <asm/reg.h>
#include <asm/time.h>
#include <asm/byteorder.h>
#include <asm/kvm_ppc.h>
#include <asm/disassemble.h>
#include "timing.h"
#include "trace.h"
#define OP_TRAP 3
#define OP_TRAP_64 2
#define OP_31_XOP_TRAP 4
#define OP_31_XOP_LWZX 23
#define OP_31_XOP_TRAP_64 68
#define OP_31_XOP_LBZX 87
#define OP_31_XOP_STWX 151
#define OP_31_XOP_STBX 215
#define OP_31_XOP_LBZUX 119
#define OP_31_XOP_STBUX 247
#define OP_31_XOP_LHZX 279
#define OP_31_XOP_LHZUX 311
#define OP_31_XOP_MFSPR 339
#define OP_31_XOP_LHAX 343
#define OP_31_XOP_STHX 407
#define OP_31_XOP_STHUX 439
#define OP_31_XOP_MTSPR 467
#define OP_31_XOP_DCBI 470
#define OP_31_XOP_LWBRX 534
#define OP_31_XOP_TLBSYNC 566
#define OP_31_XOP_STWBRX 662
#define OP_31_XOP_LHBRX 790
#define OP_31_XOP_STHBRX 918
#define OP_LWZ 32
#define OP_LWZU 33
#define OP_LBZ 34
#define OP_LBZU 35
#define OP_STW 36
#define OP_STWU 37
#define OP_STB 38
#define OP_STBU 39
#define OP_LHZ 40
#define OP_LHZU 41
#define OP_LHA 42
#define OP_LHAU 43
#define OP_STH 44
#define OP_STHU 45
void kvmppc_emulate_dec(struct kvm_vcpu *vcpu)
{
unsigned long dec_nsec;
unsigned long long dec_time;
pr_debug("mtDEC: %x\n", vcpu->arch.dec);
hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
#ifdef CONFIG_PPC_BOOK3S
/* mtdec lowers the interrupt line when positive. */
kvmppc_core_dequeue_dec(vcpu);
/* POWER4+ triggers a dec interrupt if the value is < 0 */
if (vcpu->arch.dec & 0x80000000) {
kvmppc_core_queue_dec(vcpu);
return;
}
#endif
#ifdef CONFIG_BOOKE
/* On BOOKE, DEC = 0 is as good as decrementer not enabled */
if (vcpu->arch.dec == 0)
return;
#endif
/*
* The decrementer ticks at the same rate as the timebase, so
* that's how we convert the guest DEC value to the number of
* host ticks.
*/
dec_time = vcpu->arch.dec;
/*
* Guest timebase ticks at the same frequency as host decrementer.
* So use the host decrementer calculations for decrementer emulation.
*/
dec_time = dec_time << decrementer_clockevent.shift;
do_div(dec_time, decrementer_clockevent.mult);
dec_nsec = do_div(dec_time, NSEC_PER_SEC);
hrtimer_start(&vcpu->arch.dec_timer,
ktime_set(dec_time, dec_nsec), HRTIMER_MODE_REL);
vcpu->arch.dec_jiffies = get_tb();
}
u32 kvmppc_get_dec(struct kvm_vcpu *vcpu, u64 tb)
{
u64 jd = tb - vcpu->arch.dec_jiffies;
#ifdef CONFIG_BOOKE
if (vcpu->arch.dec < jd)
return 0;
#endif
return vcpu->arch.dec - jd;
}
/* XXX to do:
* lhax
* lhaux
* lswx
* lswi
* stswx
* stswi
* lha
* lhau
* lmw
* stmw
*
* XXX is_bigendian should depend on MMU mapping or MSR[LE]
*/
/* XXX Should probably auto-generate instruction decoding for a particular core
* from opcode tables in the future. */
int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
{
u32 inst = kvmppc_get_last_inst(vcpu);
int ra = get_ra(inst);
int rs = get_rs(inst);
int rt = get_rt(inst);
int sprn = get_sprn(inst);
enum emulation_result emulated = EMULATE_DONE;
int advance = 1;
ulong spr_val = 0;
/* this default type might be overwritten by subcategories */
kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
pr_debug("Emulating opcode %d / %d\n", get_op(inst), get_xop(inst));
switch (get_op(inst)) {
case OP_TRAP:
#ifdef CONFIG_PPC_BOOK3S
case OP_TRAP_64:
kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
#else
kvmppc_core_queue_program(vcpu,
vcpu->arch.shared->esr | ESR_PTR);
#endif
advance = 0;
break;
case 31:
switch (get_xop(inst)) {
case OP_31_XOP_TRAP:
#ifdef CONFIG_64BIT
case OP_31_XOP_TRAP_64:
#endif
#ifdef CONFIG_PPC_BOOK3S
kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
#else
kvmppc_core_queue_program(vcpu,
vcpu->arch.shared->esr | ESR_PTR);
#endif
advance = 0;
break;
case OP_31_XOP_LWZX:
emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
break;
case OP_31_XOP_LBZX:
emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
break;
case OP_31_XOP_LBZUX:
emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_31_XOP_STWX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
4, 1);
break;
case OP_31_XOP_STBX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
1, 1);
break;
case OP_31_XOP_STBUX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
1, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_31_XOP_LHAX:
emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
break;
case OP_31_XOP_LHZX:
emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
break;
case OP_31_XOP_LHZUX:
emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_31_XOP_MFSPR:
switch (sprn) {
case SPRN_SRR0:
spr_val = vcpu->arch.shared->srr0;
break;
case SPRN_SRR1:
spr_val = vcpu->arch.shared->srr1;
break;
case SPRN_PVR:
spr_val = vcpu->arch.pvr;
break;
case SPRN_PIR:
spr_val = vcpu->vcpu_id;
break;
case SPRN_MSSSR0:
spr_val = 0;
break;
/* Note: mftb and TBRL/TBWL are user-accessible, so
* the guest can always access the real TB anyways.
* In fact, we probably will never see these traps. */
case SPRN_TBWL:
spr_val = get_tb() >> 32;
break;
case SPRN_TBWU:
spr_val = get_tb();
break;
case SPRN_SPRG0:
spr_val = vcpu->arch.shared->sprg0;
break;
case SPRN_SPRG1:
spr_val = vcpu->arch.shared->sprg1;
break;
case SPRN_SPRG2:
spr_val = vcpu->arch.shared->sprg2;
break;
case SPRN_SPRG3:
spr_val = vcpu->arch.shared->sprg3;
break;
/* Note: SPRG4-7 are user-readable, so we don't get
* a trap. */
case SPRN_DEC:
spr_val = kvmppc_get_dec(vcpu, get_tb());
break;
default:
emulated = kvmppc_core_emulate_mfspr(vcpu, sprn,
&spr_val);
if (unlikely(emulated == EMULATE_FAIL)) {
printk(KERN_INFO "mfspr: unknown spr "
"0x%x\n", sprn);
}
break;
}
kvmppc_set_gpr(vcpu, rt, spr_val);
kvmppc_set_exit_type(vcpu, EMULATED_MFSPR_EXITS);
break;
case OP_31_XOP_STHX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
2, 1);
break;
case OP_31_XOP_STHUX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
2, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_31_XOP_MTSPR:
spr_val = kvmppc_get_gpr(vcpu, rs);
switch (sprn) {
case SPRN_SRR0:
vcpu->arch.shared->srr0 = spr_val;
break;
case SPRN_SRR1:
vcpu->arch.shared->srr1 = spr_val;
break;
/* XXX We need to context-switch the timebase for
* watchdog and FIT. */
case SPRN_TBWL: break;
case SPRN_TBWU: break;
case SPRN_MSSSR0: break;
case SPRN_DEC:
vcpu->arch.dec = spr_val;
kvmppc_emulate_dec(vcpu);
break;
case SPRN_SPRG0:
vcpu->arch.shared->sprg0 = spr_val;
break;
case SPRN_SPRG1:
vcpu->arch.shared->sprg1 = spr_val;
break;
case SPRN_SPRG2:
vcpu->arch.shared->sprg2 = spr_val;
break;
case SPRN_SPRG3:
vcpu->arch.shared->sprg3 = spr_val;
break;
default:
emulated = kvmppc_core_emulate_mtspr(vcpu, sprn,
spr_val);
if (emulated == EMULATE_FAIL)
printk(KERN_INFO "mtspr: unknown spr "
"0x%x\n", sprn);
break;
}
kvmppc_set_exit_type(vcpu, EMULATED_MTSPR_EXITS);
break;
case OP_31_XOP_DCBI:
/* Do nothing. The guest is performing dcbi because
* hardware DMA is not snooped by the dcache, but
* emulated DMA either goes through the dcache as
* normal writes, or the host kernel has handled dcache
* coherence. */
break;
case OP_31_XOP_LWBRX:
emulated = kvmppc_handle_load(run, vcpu, rt, 4, 0);
break;
case OP_31_XOP_TLBSYNC:
break;
case OP_31_XOP_STWBRX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
4, 0);
break;
case OP_31_XOP_LHBRX:
emulated = kvmppc_handle_load(run, vcpu, rt, 2, 0);
break;
case OP_31_XOP_STHBRX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
2, 0);
break;
default:
/* Attempt core-specific emulation below. */
emulated = EMULATE_FAIL;
}
break;
case OP_LWZ:
emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
break;
case OP_LWZU:
emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_LBZ:
emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
break;
case OP_LBZU:
emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_STW:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
4, 1);
break;
case OP_STWU:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
4, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_STB:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
1, 1);
break;
case OP_STBU:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
1, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_LHZ:
emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
break;
case OP_LHZU:
emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_LHA:
emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
break;
case OP_LHAU:
emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_STH:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
2, 1);
break;
case OP_STHU:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
2, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
default:
emulated = EMULATE_FAIL;
}
if (emulated == EMULATE_FAIL) {
emulated = kvmppc_core_emulate_op(run, vcpu, inst, &advance);
if (emulated == EMULATE_AGAIN) {
advance = 0;
} else if (emulated == EMULATE_FAIL) {
advance = 0;
printk(KERN_ERR "Couldn't emulate instruction 0x%08x "
"(op %d xop %d)\n", inst, get_op(inst), get_xop(inst));
kvmppc_core_queue_program(vcpu, 0);
}
}
trace_kvm_ppc_instr(inst, kvmppc_get_pc(vcpu), emulated);
/* Advance past emulated instruction. */
if (advance)
kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
return emulated;
}
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