From: Avi Kivity <avi@redhat.com>
Date: Wed, 12 Sep 2012 10:53:08 +0000 (+0300)
Subject: KVM: MMU: Optimize gpte_access() slightly
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=edc2ae84eb40a3c062210fe01af1cae1633cc810;p=deliverable%2Flinux.git

KVM: MMU: Optimize gpte_access() slightly

If nx is disabled, then is gpte[63] is set we will hit a reserved
bit set fault before checking permissions; so we can ignore the
setting of efer.nxe.

Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index bf7b4ffafab8..064bcb32d84e 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -106,10 +106,8 @@ static unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, pt_element_t gpte)
 	unsigned access;
 
 	access = (gpte & (PT_WRITABLE_MASK | PT_USER_MASK)) | ACC_EXEC_MASK;
-
 #if PTTYPE == 64
-	if (vcpu->arch.mmu.nx)
-		access &= ~(gpte >> PT64_NX_SHIFT);
+	access &= ~(gpte >> PT64_NX_SHIFT);
 #endif
 	return access;
 }