From: Sean Christopherson sean.j.christopherson@intel.com
commit e89505698c9f70125651060547da4ff5046124fc upstream.
Call kvm_mmu_commit_zap_page() after exiting the "prepare zap" loop in kvm_recover_nx_lpages() to finish zapping pages in the unlikely event that the loop exited due to lpage_disallowed_mmu_pages being empty. Because the recovery thread drops mmu_lock() when rescheduling, it's possible that lpage_disallowed_mmu_pages could be emptied by a different thread without to_zap reaching zero despite to_zap being derived from the number of disallowed lpages.
Fixes: 1aa9b9572b105 ("kvm: x86: mmu: Recovery of shattered NX large pages") Cc: Junaid Shahid junaids@google.com Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson sean.j.christopherson@intel.com Message-Id: 20200923183735.584-2-sean.j.christopherson@intel.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kvm/mmu.c | 1 + 1 file changed, 1 insertion(+)
--- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -5321,6 +5321,7 @@ static void kvm_recover_nx_lpages(struct cond_resched_lock(&kvm->mmu_lock); } } + kvm_mmu_commit_zap_page(kvm, &invalid_list);
spin_unlock(&kvm->mmu_lock); srcu_read_unlock(&kvm->srcu, rcu_idx);