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Subject[PATCH v6 8/8] KVM: x86/mmu: WARN if TDP MMU SP disallows hugepage after being zapped
From
Extend the accounting sanity check in kvm_recover_nx_huge_pages() to the
TDP MMU, i.e. verify that zapping a shadow page unaccounts the disallowed
NX huge page regardless of the MMU type. Recovery runs while holding
mmu_lock for write and so it should be impossible to get false positives
on the WARN.

Suggested-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/mmu/mmu.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 14674c9e10f7..dfd1656232ad 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6864,12 +6864,11 @@ static void kvm_recover_nx_huge_pages(struct kvm *kvm)
struct kvm_mmu_page,
possible_nx_huge_page_link);
WARN_ON_ONCE(!sp->nx_huge_page_disallowed);
- if (is_tdp_mmu_page(sp)) {
+ if (is_tdp_mmu_page(sp))
flush |= kvm_tdp_mmu_zap_sp(kvm, sp);
- } else {
+ else
kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
- WARN_ON_ONCE(sp->nx_huge_page_disallowed);
- }
+ WARN_ON_ONCE(sp->nx_huge_page_disallowed);

if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) {
kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, flush);
--
2.38.0.413.g74048e4d9e-goog
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