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 62741b7c4223adf2deb0fc8deb3fa0939f0f8cc2..5ebb2788bd73cad5246d6993f2ce4d3fea6fc9ae 100644 (file)
--- 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;
 }