From 6f7c6d23b71af2e65056e777eeb2f1e6e0195f14 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 25 Jan 2019 07:40:54 -0800 Subject: [PATCH] KVM: VMX: Let the compiler save/load RDX during vCPU-run Per commit c20363006af6 ("KVM: VMX: Let gcc to choose which registers to save (x86_64)"), the only reason RDX is saved/loaded to/from the stack is because it was specified as an input, i.e. couldn't be marked as clobbered (ignoring the fact that "saving" it to a dummy output would indirectly mark it as clobbered). Now that RDX is no longer an input, clobber it. Reviewed-by: Jim Mattson Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/vmx.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index b935ba3306aa..e9d81cd8421f 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6377,7 +6377,7 @@ static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx) asm( /* Store host registers */ - "push %%" _ASM_DX "; push %%" _ASM_BP ";" + "push %%" _ASM_BP " \n\t" "sub $%c[wordsize], %%" _ASM_SP "\n\t" /* placeholder for guest RCX */ "push %%" _ASM_CX " \n\t" "sub $%c[wordsize], %%" _ASM_SP "\n\t" /* temporarily adjust RSP for CALL */ @@ -6481,7 +6481,7 @@ 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 %%" _ASM_BP "; pop %%" _ASM_DX " \n\t" + "pop %%" _ASM_BP " \n\t" : ASM_CALL_CONSTRAINT, "=S"((int){0}) : "c"(vmx), "S"(evmcs_rsp), [launched]"i"(offsetof(struct vcpu_vmx, __launched)), @@ -6509,10 +6509,10 @@ static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx) [wordsize]"i"(sizeof(ulong)) : "cc", "memory" #ifdef CONFIG_X86_64 - , "rax", "rbx", "rdi" + , "rax", "rbx", "rdx", "rdi" , "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15" #else - , "eax", "ebx", "edi" + , "eax", "ebx", "edx", "edi" #endif ); } -- 2.39.5