As x86_64 ABI defines some registers saved by the calling function, it is not
needed to save all registers in the called function when switching to VCPU.
(see http://www.x86-64.org/documentation/abi.pdf, chapter 3.2.1)
The best way to do that is to inform GCC which registers we use and let
it to save only needed registers.
Signed-off-by: Laurent Vivier <[EMAIL PROTECTED]>
---
drivers/kvm/vmx.c | 21 +++++++++------------
1 files changed, 9 insertions(+), 12 deletions(-)
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 2c6b64a..d6c91ac 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -2243,16 +2243,12 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct
kvm_run *kvm_run)
asm(
/* Store host registers */
#ifdef CONFIG_X86_64
- "push %%rax; push %%rbx; push %%rdx;"
- "push %%rsi; push %%rdi; push %%rbp;"
- "push %%r8; push %%r9; push %%r10; push %%r11;"
- "push %%r12; push %%r13; push %%r14; push %%r15;"
+ "push %%rdx; push %%rbp;"
"push %%rcx \n\t"
- ASM_VMX_VMWRITE_RSP_RDX "\n\t"
#else
"pusha; push %%ecx \n\t"
- ASM_VMX_VMWRITE_RSP_RDX "\n\t"
#endif
+ ASM_VMX_VMWRITE_RSP_RDX "\n\t"
/* Check if vmlaunch of vmresume is needed */
"cmp $0, %1 \n\t"
/* Load guest registers. Don't clobber flags. */
@@ -2311,12 +2307,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct
kvm_run *kvm_run)
"mov %%r15, %c[r15](%3) \n\t"
"mov %%cr2, %%rax \n\t"
"mov %%rax, %c[cr2](%3) \n\t"
- "mov (%%rsp), %3 \n\t"
- "pop %%rcx; pop %%r15; pop %%r14; pop %%r13; pop %%r12;"
- "pop %%r11; pop %%r10; pop %%r9; pop %%r8;"
- "pop %%rbp; pop %%rdi; pop %%rsi;"
- "pop %%rdx; pop %%rbx; pop %%rax \n\t"
+ "pop %%rcx; pop %%rbp; pop %%rdx \n\t"
#else
"xchg %3, (%%esp) \n\t"
"mov %%eax, %c[rax](%3) \n\t"
@@ -2354,7 +2346,12 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct
kvm_run *kvm_run)
[r15]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_R15])),
#endif
[cr2]"i"(offsetof(struct kvm_vcpu, cr2))
- : "cc", "memory");
+ : "cc", "memory",
+#ifdef CONFIG_X86_64
+ "rbx", "rdi", "rsi",
+ "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15"
+#endif
+ );
vcpu->interrupt_window_open =
(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & 3) == 0;
--
1.5.2.4
-------------------------------------------------------------------------
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