[PATCH 5.10 001/130] KVM/VMX: Use TEST %REG,%REG instead of CMP $0,%REG in vmenter.S

Greg Kroah-Hartman
2022-07-12T18:40:24Z

From: Uros Bizjak <ubizjak@gmail.com>

commit 6c44221b05236cc65d76cb5dc2463f738edff39d upstream.

Saves one byte in __vmx_vcpu_run for the same functionality.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Message-Id: <20201029140457.126965-1-ubizjak@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kvm/vmx/vmenter.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kvm/vmx/vmenter.S
+++ b/arch/x86/kvm/vmx/vmenter.S
@@ -132,7 +132,7 @@ SYM_FUNC_START(__vmx_vcpu_run)
mov (%_ASM_SP), %_ASM_AX

/* Check if vmlaunch or vmresume is needed */
- cmpb $0, %bl
+ testb %bl, %bl

/* Load guest registers. Don't clobber flags. */
mov VCPU_RCX(%_ASM_AX), %_ASM_CX