1 files changed, 8 insertions, 0 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a5d6ef785b7e..685a48557389 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -556,6 +556,14 @@ static int mmu_spte_clear_track_bits(u64 *sptep)
                 return 0;
 
         pfn = spte_to_pfn(old_spte);
+
+        /*
+         * KVM does not hold the refcount of the page used by
+         * kvm mmu, before reclaiming the page, we should
+         * unmap it from mmu first.
+         */
+        WARN_ON(!kvm_is_mmio_pfn(pfn) && !page_count(pfn_to_page(pfn)));
+
         if (!shadow_accessed_mask || old_spte & shadow_accessed_mask)
                 kvm_set_pfn_accessed(pfn);
         if (!shadow_dirty_mask || (old_spte & shadow_dirty_mask))