| Message ID | 20181220203035.23041-1-sean.j.christopherson@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: VMX: Clean up VM-Enter/VM-Exit asm code | expand |
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 5d07d385b637..1821fb9ac009 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6219,7 +6219,7 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu) "xor %%esi, %%esi \n\t" "xor %%edi, %%edi \n\t" "pop %%" _ASM_BP "; pop %%" _ASM_DX " \n\t" - : ASM_CALL_CONSTRAINT + : ASM_CALL_CONSTRAINT, "=S"((int){0}) : "c"(vmx), "d"((unsigned long)HOST_RSP), "S"(evmcs_rsp), [launched]"i"(offsetof(struct vcpu_vmx, __launched)), [fail]"i"(offsetof(struct vcpu_vmx, fail)),
RSI is clobbered by the VM-Enter asm blob in vmx_vcpu_run(), but it's not marked as such, probably because GCC doesn't let you mark inputs as clobbered. "Save" RSI to a dummy output so that GCC recognizes it as being clobbered. Note that this has a funky dependency on removing the 'vmx_return' global variable definition from vmx_vcpu_run()'s asm blob (done in a prior patch), as attempting to declare RSI as output would generate a cryptic compiler error that magically disappeared when vmx_return was eliminated. Fixes: 773e8a0425c9 ("x86/kvm: use Enlightened VMCS when running on Hyper-V") Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> --- arch/x86/kvm/vmx/vmx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)