linux-kernel - [PATCH] kvm:vmx:code changes in handle

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Message-Id: <1607588115-29971-1-git-send-email-starzhangzsd@gmail.com>
Date:   Thu, 10 Dec 2020 16:15:15 +0800
From:   Stephen Zhang <starzhangzsd@...il.com>
To:     pbonzini@...hat.com, seanjc@...gle.com, vkuznets@...hat.com,
        wanpengli@...cent.com, jmattson@...gle.com, joro@...tes.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, x86@...nel.org,
        hpa@...or.com
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Stephen Zhang <starzhangzsd@...il.com>
Subject: [PATCH] kvm:vmx:code changes in handle_io() to save some CPU cycles.

code changes in handle_io() to save some CPU cycles.

Signed-off-by: Stephen Zhang <starzhangzsd@...il.com>
---
 arch/x86/kvm/vmx/vmx.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 47b8357..109bcf64 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -4899,15 +4899,14 @@ static int handle_triple_fault(struct kvm_vcpu *vcpu)
 static int handle_io(struct kvm_vcpu *vcpu)
 {
 	unsigned long exit_qualification;
-	int size, in, string;
+	int size, in;
 	unsigned port;
 
 	exit_qualification = vmx_get_exit_qual(vcpu);
-	string = (exit_qualification & 16) != 0;
 
 	++vcpu->stat.io_exits;
 
-	if (string)
+	if (exit_qualification & 16)
 		return kvm_emulate_instruction(vcpu, 0);
 
 	port = exit_qualification >> 16;
-- 
1.8.3.1