Messages in this thread Patch in this message | | | From | Avi Kivity <> | Subject | [PATCH 14/55] KVM: SVM: Let gcc to choose which registers to save (i386) | Date | Wed, 26 Dec 2007 13:05:19 +0200 |
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From: Laurent Vivier <Laurent.Vivier@bull.net>
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 <Laurent.Vivier@bull.net> Signed-off-by: Avi Kivity <avi@qumranet.com> --- 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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