linux-kernel - [PATCH v2] KVM: x86: add paging gcc optimization

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Date:	Thu, 08 Mar 2012 12:45:54 +0100
From:	Davidlohr Bueso <dave@....org>
To:	Avi Kivity <avi@...hat.com>, Marcelo Tosatti <mtosatti@...hat.com>
Cc:	KVM <kvm@...r.kernel.org>, lkml <linux-kernel@...r.kernel.org>
Subject: [PATCH v2] KVM: x86: add paging gcc optimization

From: Davidlohr Bueso <dave@....org>

Since most guests will have paging enabled for memory management, add likely() optimization
around CR0.PG checks.

Signed-off-by: Davidlohr Bueso <dave@....org>
---
 arch/x86/kvm/x86.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index cb80c29..3d1134d 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -64,7 +64,7 @@ static inline int is_pse(struct kvm_vcpu *vcpu)
 
 static inline int is_paging(struct kvm_vcpu *vcpu)
 {
-	return kvm_read_cr0_bits(vcpu, X86_CR0_PG);
+	return likely(kvm_read_cr0_bits(vcpu, X86_CR0_PG));
 }
 
 static inline u32 bit(int bitno)
-- 
1.7.8.3



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