[PATCH v2 24/28] KVM: x86/mmu: Do not prefetch sptes on gfns backed by memory attributes

[Paolo Bonzini]

From: Nicolas Saenz Julienne <nsaenz@xxxxxxxxxx>

Prefetched SPTEs are always given full access.  Do not prefetch GFNs
that have memory protections applied.

Signed-off-by: Nicolas Saenz Julienne <nsaenz@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
 arch/x86/kvm/mmu/mmu.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 3fd4cc3c57a5..097095f71d60 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3187,6 +3187,11 @@ static bool kvm_mmu_prefetch_sptes(struct kvm_vcpu *vcpu, gfn_t gfn, u64 *sptep,
 		return false;
 
 	for (i = 0; i < nr_pages; i++, gfn++, sptep++) {
+		if (!kvm_get_memory_attributes(vcpu->kvm, gfn)) {
+			kvm_release_page_clean(pages[i]);
+			continue;
+		}
+
 		mmu_set_spte(vcpu, slot, sptep, access, gfn,
 			     page_to_pfn(pages[i]), NULL);
 
-- 
2.52.0