From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Mingwei Zhang <mizhang@google.com>,
David Matlack <dmatlack@google.com>,
Yan Zhao <yan.y.zhao@intel.com>, Ben Gardon <bgardon@google.com>
Subject: [PATCH v6 8/8] KVM: x86/mmu: WARN if TDP MMU SP disallows hugepage after being zapped
Date: Wed, 19 Oct 2022 16:56:18 +0000 [thread overview]
Message-ID: <20221019165618.927057-9-seanjc@google.com> (raw)
In-Reply-To: <20221019165618.927057-1-seanjc@google.com>
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
next prev parent reply other threads:[~2022-10-19 16:57 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-19 16:56 [PATCH v6 0/8] KVM: x86: Apply NX mitigation more precisely Sean Christopherson
2022-10-19 16:56 ` [PATCH v6 1/8] KVM: x86/mmu: Tag disallowed NX huge pages even if they're not tracked Sean Christopherson
2022-10-19 16:56 ` [PATCH v6 2/8] KVM: x86/mmu: Rename NX huge pages fields/functions for consistency Sean Christopherson
2022-10-19 16:56 ` [PATCH v6 3/8] KVM: x86/mmu: Properly account NX huge page workaround for nonpaging MMUs Sean Christopherson
2022-10-19 16:56 ` [PATCH v6 4/8] KVM: x86/mmu: Set disallowed_nx_huge_page in TDP MMU before setting SPTE Sean Christopherson
2022-10-21 5:46 ` Yan Zhao
2022-10-19 16:56 ` [PATCH v6 5/8] KVM: x86/mmu: Track the number of TDP MMU pages, but not the actual pages Sean Christopherson
2022-10-21 5:42 ` Yan Zhao
2022-10-19 16:56 ` [PATCH v6 6/8] KVM: x86/mmu: Add helper to convert SPTE value to its shadow page Sean Christopherson
2022-10-19 16:56 ` [PATCH v6 7/8] KVM: x86/mmu: explicitly check nx_hugepage in disallowed_hugepage_adjust() Sean Christopherson
2022-10-21 5:41 ` Yan Zhao
2022-10-19 16:56 ` Sean Christopherson [this message]
2022-10-21 5:41 ` [PATCH v6 8/8] KVM: x86/mmu: WARN if TDP MMU SP disallows hugepage after being zapped Yan Zhao
2022-11-02 17:35 ` [PATCH v6 0/8] KVM: x86: Apply NX mitigation more precisely Paolo Bonzini
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