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 9dc0c2deb9aad46dc61cb4bcd63bf387744adcbb..491f64508269ffccedde42ba0232ae7917a77eaa 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -849,7 +849,10 @@ 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;
 }