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From: Stephen Zhang <starzhangzsd@gmail.com>
To: pbonzini@redhat.com, seanjc@google.com, vkuznets@redhat.com,
	wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org,
	tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	x86@kernel.org, hpa@zytor.com
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Stephen Zhang <starzhangzsd@gmail.com>
Subject: [PATCH] kvm:vmx:code changes in handle_io() to save some CPU cycles.
Date: Thu, 10 Dec 2020 16:15:15 +0800	[thread overview]
Message-ID: <1607588115-29971-1-git-send-email-starzhangzsd@gmail.com> (raw)

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

Signed-off-by: Stephen Zhang <starzhangzsd@gmail.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


             reply	other threads:[~2020-12-10  8:16 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-10  8:15 Stephen Zhang [this message]
2020-12-10  9:56 ` [PATCH] kvm:vmx:code changes in handle_io() to save some CPU cycles Vitaly Kuznetsov
2020-12-12  0:34 ` Paolo Bonzini

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