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linux-pinenote/arch/powerpc/kernel/kvm_emul.S
Alexander Graf df08bd1026 KVM: PPC: Make PV mtmsrd L=1 work with r30 and r31 
We had an arbitrary limitation in mtmsrd L=1 that kept us from using r30 and
r31 as input registers. Let's get rid of that and get more potential speedups!

Signed-off-by: Alexander Graf <agraf@suse.de>
2010-10-24 10:52:14 +02:00

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7.2 KiB
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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 SUSE Linux Products GmbH 2010
*
* Authors: Alexander Graf <agraf@suse.de>
*/
#include <asm/ppc_asm.h>
#include <asm/kvm_asm.h>
#include <asm/reg.h>
#include <asm/page.h>
#include <asm/asm-offsets.h>
/* Hypercall entry point. Will be patched with device tree instructions. */
.global kvm_hypercall_start
kvm_hypercall_start:
li r3, -1
nop
nop
nop
blr
#define KVM_MAGIC_PAGE (-4096)
#ifdef CONFIG_64BIT
#define LL64(reg, offs, reg2) ld reg, (offs)(reg2)
#define STL64(reg, offs, reg2) std reg, (offs)(reg2)
#else
#define LL64(reg, offs, reg2) lwz reg, (offs + 4)(reg2)
#define STL64(reg, offs, reg2) stw reg, (offs + 4)(reg2)
#endif
#define SCRATCH_SAVE \
/* Enable critical section. We are critical if \
shared->critical == r1 */ \
STL64(r1, KVM_MAGIC_PAGE + KVM_MAGIC_CRITICAL, 0); \
\
/* Save state */ \
PPC_STL r31, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH1)(0); \
PPC_STL r30, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH2)(0); \
mfcr r31; \
stw r31, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH3)(0);
#define SCRATCH_RESTORE \
/* Restore state */ \
PPC_LL r31, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH1)(0); \
lwz r30, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH3)(0); \
mtcr r30; \
PPC_LL r30, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH2)(0); \
\
/* Disable critical section. We are critical if \
shared->critical == r1 and r2 is always != r1 */ \
STL64(r2, KVM_MAGIC_PAGE + KVM_MAGIC_CRITICAL, 0);
.global kvm_emulate_mtmsrd
kvm_emulate_mtmsrd:
SCRATCH_SAVE
/* Put MSR & ~(MSR_EE|MSR_RI) in r31 */
LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
lis r30, (~(MSR_EE | MSR_RI))@h
ori r30, r30, (~(MSR_EE | MSR_RI))@l
and r31, r31, r30
/* OR the register's (MSR_EE|MSR_RI) on MSR */
kvm_emulate_mtmsrd_reg:
ori r30, r0, 0
andi. r30, r30, (MSR_EE|MSR_RI)
or r31, r31, r30
/* Put MSR back into magic page */
STL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
/* Check if we have to fetch an interrupt */
lwz r31, (KVM_MAGIC_PAGE + KVM_MAGIC_INT)(0)
cmpwi r31, 0
beq+ no_check
/* Check if we may trigger an interrupt */
andi. r30, r30, MSR_EE
beq no_check
SCRATCH_RESTORE
/* Nag hypervisor */
kvm_emulate_mtmsrd_orig_ins:
tlbsync
b kvm_emulate_mtmsrd_branch
no_check:
SCRATCH_RESTORE
/* Go back to caller */
kvm_emulate_mtmsrd_branch:
b .
kvm_emulate_mtmsrd_end:
.global kvm_emulate_mtmsrd_branch_offs
kvm_emulate_mtmsrd_branch_offs:
.long (kvm_emulate_mtmsrd_branch - kvm_emulate_mtmsrd) / 4
.global kvm_emulate_mtmsrd_reg_offs
kvm_emulate_mtmsrd_reg_offs:
.long (kvm_emulate_mtmsrd_reg - kvm_emulate_mtmsrd) / 4
.global kvm_emulate_mtmsrd_orig_ins_offs
kvm_emulate_mtmsrd_orig_ins_offs:
.long (kvm_emulate_mtmsrd_orig_ins - kvm_emulate_mtmsrd) / 4
.global kvm_emulate_mtmsrd_len
kvm_emulate_mtmsrd_len:
.long (kvm_emulate_mtmsrd_end - kvm_emulate_mtmsrd) / 4
#define MSR_SAFE_BITS (MSR_EE | MSR_CE | MSR_ME | MSR_RI)
#define MSR_CRITICAL_BITS ~MSR_SAFE_BITS
.global kvm_emulate_mtmsr
kvm_emulate_mtmsr:
SCRATCH_SAVE
/* Fetch old MSR in r31 */
LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
/* Find the changed bits between old and new MSR */
kvm_emulate_mtmsr_reg1:
ori r30, r0, 0
xor r31, r30, r31
/* Check if we need to really do mtmsr */
LOAD_REG_IMMEDIATE(r30, MSR_CRITICAL_BITS)
and. r31, r31, r30
/* No critical bits changed? Maybe we can stay in the guest. */
beq maybe_stay_in_guest
do_mtmsr:
SCRATCH_RESTORE
/* Just fire off the mtmsr if it's critical */
kvm_emulate_mtmsr_orig_ins:
mtmsr r0
b kvm_emulate_mtmsr_branch
maybe_stay_in_guest:
/* Get the target register in r30 */
kvm_emulate_mtmsr_reg2:
ori r30, r0, 0
/* Check if we have to fetch an interrupt */
lwz r31, (KVM_MAGIC_PAGE + KVM_MAGIC_INT)(0)
cmpwi r31, 0
beq+ no_mtmsr
/* Check if we may trigger an interrupt */
andi. r31, r30, MSR_EE
beq no_mtmsr
b do_mtmsr
no_mtmsr:
/* Put MSR into magic page because we don't call mtmsr */
STL64(r30, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
SCRATCH_RESTORE
/* Go back to caller */
kvm_emulate_mtmsr_branch:
b .
kvm_emulate_mtmsr_end:
.global kvm_emulate_mtmsr_branch_offs
kvm_emulate_mtmsr_branch_offs:
.long (kvm_emulate_mtmsr_branch - kvm_emulate_mtmsr) / 4
.global kvm_emulate_mtmsr_reg1_offs
kvm_emulate_mtmsr_reg1_offs:
.long (kvm_emulate_mtmsr_reg1 - kvm_emulate_mtmsr) / 4
.global kvm_emulate_mtmsr_reg2_offs
kvm_emulate_mtmsr_reg2_offs:
.long (kvm_emulate_mtmsr_reg2 - kvm_emulate_mtmsr) / 4
.global kvm_emulate_mtmsr_orig_ins_offs
kvm_emulate_mtmsr_orig_ins_offs:
.long (kvm_emulate_mtmsr_orig_ins - kvm_emulate_mtmsr) / 4
.global kvm_emulate_mtmsr_len
kvm_emulate_mtmsr_len:
.long (kvm_emulate_mtmsr_end - kvm_emulate_mtmsr) / 4
.global kvm_emulate_wrteei
kvm_emulate_wrteei:
SCRATCH_SAVE
/* Fetch old MSR in r31 */
LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
/* Remove MSR_EE from old MSR */
li r30, 0
ori r30, r30, MSR_EE
andc r31, r31, r30
/* OR new MSR_EE onto the old MSR */
kvm_emulate_wrteei_ee:
ori r31, r31, 0
/* Write new MSR value back */
STL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
SCRATCH_RESTORE
/* Go back to caller */
kvm_emulate_wrteei_branch:
b .
kvm_emulate_wrteei_end:
.global kvm_emulate_wrteei_branch_offs
kvm_emulate_wrteei_branch_offs:
.long (kvm_emulate_wrteei_branch - kvm_emulate_wrteei) / 4
.global kvm_emulate_wrteei_ee_offs
kvm_emulate_wrteei_ee_offs:
.long (kvm_emulate_wrteei_ee - kvm_emulate_wrteei) / 4
.global kvm_emulate_wrteei_len
kvm_emulate_wrteei_len:
.long (kvm_emulate_wrteei_end - kvm_emulate_wrteei) / 4
.global kvm_emulate_mtsrin
kvm_emulate_mtsrin:
SCRATCH_SAVE
LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
andi. r31, r31, MSR_DR | MSR_IR
beq kvm_emulate_mtsrin_reg1
SCRATCH_RESTORE
kvm_emulate_mtsrin_orig_ins:
nop
b kvm_emulate_mtsrin_branch
kvm_emulate_mtsrin_reg1:
/* rX >> 26 */
rlwinm r30,r0,6,26,29
kvm_emulate_mtsrin_reg2:
stw r0, (KVM_MAGIC_PAGE + KVM_MAGIC_SR)(r30)
SCRATCH_RESTORE
/* Go back to caller */
kvm_emulate_mtsrin_branch:
b .
kvm_emulate_mtsrin_end:
.global kvm_emulate_mtsrin_branch_offs
kvm_emulate_mtsrin_branch_offs:
.long (kvm_emulate_mtsrin_branch - kvm_emulate_mtsrin) / 4
.global kvm_emulate_mtsrin_reg1_offs
kvm_emulate_mtsrin_reg1_offs:
.long (kvm_emulate_mtsrin_reg1 - kvm_emulate_mtsrin) / 4
.global kvm_emulate_mtsrin_reg2_offs
kvm_emulate_mtsrin_reg2_offs:
.long (kvm_emulate_mtsrin_reg2 - kvm_emulate_mtsrin) / 4
.global kvm_emulate_mtsrin_orig_ins_offs
kvm_emulate_mtsrin_orig_ins_offs:
.long (kvm_emulate_mtsrin_orig_ins - kvm_emulate_mtsrin) / 4
.global kvm_emulate_mtsrin_len
kvm_emulate_mtsrin_len:
.long (kvm_emulate_mtsrin_end - kvm_emulate_mtsrin) / 4
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