From 868388c7cf13ee4c744dd306c7f8305f85b6b1f5 Mon Sep 17 00:00:00 2001 From: David Matlack Date: Thu, 13 Jan 2022 23:30:18 +0000 Subject: [PATCH] KVM: x86/mmu: Clear MMU-writable during changed_pte notifier 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 aforementioned invariant and technically the changed_pte notifier is dead code. Signed-off-by: David Matlack Message-Id: <20220113233020.3986005-3-dmatlack@google.com> Reviewed-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- 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 8a7b03207762a..f8677404c93cb 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); -- 2.39.5