[PATCH v2 2/4] KVM: x86/mmu: Clear MMU-writable during changed_pte notifier

[David Matlack <dmatlack@google.com>]

When handling the changed_pte notifier and the new PTE is read-only,
clear both the Host-writable and MMU-writable bits in the SPTE. This
preserves the invariant that MMU-writable is set if-and-only-if
Host-writable is set.

No functional change intended. Nothing currently relies on the
afformentioned invariant and technically the changed_pte notifier is
dead code.

Signed-off-by: David Matlack <dmatlack@google.com>
---
 arch/x86/kvm/mmu/spte.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c
index 8a7b03207762..f8677404c93c 100644
--- a/arch/x86/kvm/mmu/spte.c
+++ b/arch/x86/kvm/mmu/spte.c
@@ -215,6 +215,7 @@ u64 kvm_mmu_changed_pte_notifier_make_spte(u64 old_spte, kvm_pfn_t new_pfn)
 
 	new_spte &= ~PT_WRITABLE_MASK;
 	new_spte &= ~shadow_host_writable_mask;
+	new_spte &= ~shadow_mmu_writable_mask;
 
 	new_spte = mark_spte_for_access_track(new_spte);
 
-- 
2.34.1.703.g22d0c6ccf7-goog