From: Avi Kivity <avi@qumranet.com>
Date: Thu, 29 May 2008 11:56:28 +0000 (+0300)
Subject: KVM: MMU: Avoid page prefetch on SVM
X-Git-Tag: v2.6.27-rc1~968^2~38
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=131d82791b628d4aeafd94ddc74a9b68f3d15a83;p=linux-2.6

KVM: MMU: Avoid page prefetch on SVM

SVM cannot benefit from page prefetching since guest page fault bypass
cannot by made to work there.  Avoid accessing the guest page table in
this case.

Signed-off-by: Avi Kivity <avi@qumranet.com>
---

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 62741b7c42..5ebb2788bd 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -850,7 +850,10 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
 	hlist_add_head(&sp->hash_link, bucket);
 	if (!metaphysical)
 		rmap_write_protect(vcpu->kvm, gfn);
-	vcpu->arch.mmu.prefetch_page(vcpu, sp);
+	if (shadow_trap_nonpresent_pte != shadow_notrap_nonpresent_pte)
+		vcpu->arch.mmu.prefetch_page(vcpu, sp);
+	else
+		nonpaging_prefetch_page(vcpu, sp);
 	return sp;
 }