Commit 87aa9ec9 authored by Ben Gardon's avatar Ben Gardon Committed by Paolo Bonzini
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KVM: x86/mmu: Fix TDP MMU zap collapsible SPTEs 



There is a bug in the TDP MMU function to zap SPTEs which could be
replaced with a larger mapping which prevents the function from doing
anything. Fix this by correctly zapping the last level SPTEs.

Cc: stable@vger.kernel.org
Fixes: 14881998 ("kvm: x86/mmu: Support disabling dirty logging for the tdp MMU")
Signed-off-by: default avatarBen Gardon <bgardon@google.com>
Message-Id: <20210202185734.1680553-11-bgardon@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent c1c35cf7

arch/x86/kvm/mmu/tdp_mmu.c

+3 −3
Original line number Diff line number Diff line
@@ -1049,8 +1049,8 @@ bool kvm_tdp_mmu_slot_set_dirty(struct kvm *kvm, struct kvm_memory_slot *slot) 
}



/*

 * Clear non-leaf entries (and free associated page tables) which could

 * be replaced by large mappings, for GFNs within the slot.

 * Clear leaf entries which could be replaced by large mappings, for

 * GFNs within the slot.

 */

static void zap_collapsible_spte_range(struct kvm *kvm,

				       struct kvm_mmu_page *root,
@@ -1062,7 +1062,7 @@ static void zap_collapsible_spte_range(struct kvm *kvm, 


	tdp_root_for_each_pte(iter, root, start, end) {

		if (!is_shadow_present_pte(iter.old_spte) ||

		    is_last_spte(iter.old_spte, iter.level))

		    !is_last_spte(iter.old_spte, iter.level))

			continue;



		pfn = spte_to_pfn(iter.old_spte);