From: Laurent Vivier <[email protected]>
This patch lets GCC to determine which registers to save when we
switch to/from a VCPU in the case of AMD i386
* Original code saves following registers:
ebx, ecx, edx, esi, edi, ebp
* Patched code:
- informs GCC that we modify following registers
using the clobber description:
ebx, ecx, edx, esi, edi
- rbp is saved (pop/push) because GCC seems to ignore its use in the clobber
description.
Signed-off-by: Laurent Vivier <[email protected]>
Signed-off-by: Avi Kivity <[email protected]>
---
drivers/kvm/svm.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index 1298bde..cdd4fd2 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -1501,8 +1501,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
#ifdef CONFIG_X86_64
"push %%rbp; \n\t"
#else
- "push %%ebx; push %%ecx; push %%edx;"
- "push %%esi; push %%edi; push %%ebp;"
+ "push %%ebp; \n\t"
#endif
#ifdef CONFIG_X86_64
@@ -1573,8 +1572,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
"mov %%edi, %c[rdi](%[svm]) \n\t"
"mov %%ebp, %c[rbp](%[svm]) \n\t"
- "pop %%ebp; pop %%edi; pop %%esi;"
- "pop %%edx; pop %%ecx; pop %%ebx; \n\t"
+ "pop %%ebp; \n\t"
#endif
:
: [svm]"a"(svm),
@@ -1599,6 +1597,8 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
#ifdef CONFIG_X86_64
, "rbx", "rcx", "rdx", "rsi", "rdi"
, "r8", "r9", "r10", "r11" , "r12", "r13", "r14", "r15"
+#else
+ , "ebx", "ecx", "edx" , "esi", "edi"
#endif
);
--
1.5.3.7
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