From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
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@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Message-Id: <20200923183735.584-2-sean.j.christopherson@xxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
