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authorSean Christopherson <sean.j.christopherson@intel.com>2019-01-25 07:41:06 -0800
committerPaolo Bonzini <pbonzini@redhat.com>2019-02-12 13:12:25 +0100
commit217aaff53c25f03b1d2fc23eff9dc2bae34f690e (patch)
treed00cf0b9fb832403cb21ed88b0464e0e7351b63f
parentc9afc58cc368623aaa34a62e321eea2a59240f6f (diff)
downloadlinux-stericsson-217aaff53c25f03b1d2fc23eff9dc2bae34f690e.tar.gz
KVM: VMX: Invert the ordering of saving guest/host scratch reg at VM-Enter
Switching the ordering allows for an out-of-line path for VM-Fail that elides saving guest state but still shares the register clearing with the VM-Exit path. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/x86/kvm/vmx/vmx.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 996a13ea86cc..79b42197ed7e 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6382,7 +6382,6 @@ static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx)
asm(
/* Store host registers */
"push %%" _ASM_BP " \n\t"
- "sub $%c[wordsize], %%" _ASM_SP "\n\t" /* placeholder for guest RCX */
"push %%" _ASM_ARG1 " \n\t"
/* Adjust RSP to account for the CALL to vmx_vmenter(). */
@@ -6418,11 +6417,11 @@ static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx)
/* Enter guest mode */
"call vmx_vmenter\n\t"
- /* Save guest's RCX to the stack placeholder (see above) */
- "mov %%" _ASM_CX ", %c[wordsize](%%" _ASM_SP ") \n\t"
+ /* Temporarily save guest's RCX. */
+ "push %%" _ASM_CX " \n\t"
- /* Load host's RCX, i.e. the vmx_vcpu pointer */
- "pop %%" _ASM_CX " \n\t"
+ /* Reload the vcpu_vmx pointer to RCX. */
+ "mov %c[wordsize](%%" _ASM_SP "), %%" _ASM_CX " \n\t"
/* Set vmx->fail based on EFLAGS.{CF,ZF} */
"setbe %c[fail](%%" _ASM_CX ")\n\t"
@@ -6469,6 +6468,9 @@ static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx)
"xor %%esi, %%esi \n\t"
"xor %%edi, %%edi \n\t"
"xor %%ebp, %%ebp \n\t"
+
+ /* "POP" the vcpu_vmx pointer. */
+ "add $%c[wordsize], %%" _ASM_SP " \n\t"
"pop %%" _ASM_BP " \n\t"
: ASM_CALL_CONSTRAINT, "=b"((int){0}),
#ifdef CONFIG_X86_64