Commit 574c3c55 authored by Ben Gardon's avatar Ben Gardon Committed by Paolo Bonzini
Browse files

KVM: x86/mmu: Fix TLB flush range when handling disconnected pt 



When recursively clearing out disconnected pts, the range based TLB
flush in handle_removed_tdp_mmu_page uses the wrong starting GFN,
resulting in the flush mostly missing the affected range. Fix this by
using base_gfn for the flush.

In response to feedback from David Matlack on the RFC version of this
patch, also move a few definitions into the for loop in the function to
prevent unintended references to them in the future.

Fixes: a066e61f ("KVM: x86/mmu: Factor out handling of removed page tables")
CC: stable@vger.kernel.org
Signed-off-by: default avatarBen Gardon <bgardon@google.com>
Message-Id: <20211115211704.2621644-1-bgardon@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 2845e735

arch/x86/kvm/mmu/tdp_mmu.c

+4 −6
Original line number Diff line number Diff line
@@ -317,9 +317,6 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt, 
	struct kvm_mmu_page *sp = sptep_to_sp(rcu_dereference(pt));

	int level = sp->role.level;

	gfn_t base_gfn = sp->gfn;

	u64 old_child_spte;

	u64 *sptep;

	gfn_t gfn;

	int i;



	trace_kvm_mmu_prepare_zap_page(sp);
@@ -327,8 +324,9 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt, 
	tdp_mmu_unlink_page(kvm, sp, shared);



	for (i = 0; i < PT64_ENT_PER_PAGE; i++) {

		sptep = rcu_dereference(pt) + i;

		gfn = base_gfn + i * KVM_PAGES_PER_HPAGE(level);

		u64 *sptep = rcu_dereference(pt) + i;

		gfn_t gfn = base_gfn + i * KVM_PAGES_PER_HPAGE(level);

		u64 old_child_spte;



		if (shared) {

			/*
@@ -374,7 +372,7 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt, 
				    shared);

	}



	kvm_flush_remote_tlbs_with_address(kvm, gfn,

	kvm_flush_remote_tlbs_with_address(kvm, base_gfn,

					   KVM_PAGES_PER_HPAGE(level + 1));



	call_rcu(&sp->rcu_head, tdp_mmu_free_sp_rcu_callback);