[PATCH] KVM: x86/mmu: Zap only relevant last/leaf sptes when removing a memslot

[Sean Christopherson]

Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
 arch/x86/kvm/mmu/mmu.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 3dd0af7e75151..9f468337f832c 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5810,7 +5810,18 @@ static void kvm_mmu_invalidate_zap_pages_in_memslot(struct kvm *kvm,
 			struct kvm_memory_slot *slot,
 			struct kvm_page_track_notifier_node *node)
 {
-	kvm_mmu_zap_all_fast(kvm);
+	bool flush;
+
+	/*
+	 * Zapping non-leaf SPTEs, a.k.a. not-last SPTEs, isn't required, worst
+	 * case scenario we'll have unused shadow pages lying around until they
+	 * are recycled due to age or when the VM is destroyed.
+	 */
+	spin_lock(&kvm->mmu_lock);
+	flush = slot_handle_all_level(kvm, slot, kvm_zap_rmapp, true);
+	if (flush)
+		kvm_flush_remote_tlbs(kvm);
+	spin_unlock(&kvm->mmu_lock);
 }
 
 void kvm_mmu_init_vm(struct kvm *kvm)
-- 
2.26.0


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