[PATCH] KVM: x86/mmu: Fix NX page unaccounting for TDP MMU pages

From: Carlos López

Date: Tue Sep 15 2026 - 16:36:03 EST


unaccount_nx_huge_page() unconditionally passes KVM_SHADOW_MMU to
untrack_possible_nx_huge_page(), which is incorrect, particularly on
the path from kvm_recover_nx_huge_pages(), which handles pages from
both MMUs. Fix this by retrieving the MMU type via is_tdp_mmu_page()
and passing it down.

Fixes: 6777885605e1 ("KVM: x86/mmu: Track possible NX huge pages separately for TDP vs. Shadow MMU")
Signed-off-by: Carlos López <clopez@xxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 9788ff180374..61996669b6f6 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -866,9 +866,11 @@ void untrack_possible_nx_huge_page(struct kvm *kvm, struct kvm_mmu_page *sp,

static void unaccount_nx_huge_page(struct kvm *kvm, struct kvm_mmu_page *sp)
{
+ enum kvm_mmu_type mmu_type = is_tdp_mmu_page(sp) ? KVM_TDP_MMU : KVM_SHADOW_MMU;
+
sp->nx_huge_page_disallowed = false;

- untrack_possible_nx_huge_page(kvm, sp, KVM_SHADOW_MMU);
+ untrack_possible_nx_huge_page(kvm, sp, mmu_type);
}

static struct kvm_memory_slot *gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu,

base-commit: 70c944caf570fda2d79baa71435589a8db39f048
--
2.51.0