From 0fd460446912dd96fd1e08995f57b14806c10478 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Thu, 16 Apr 2020 11:59:10 -0400 Subject: KVM: X86: Sanity check on gfn before removal The index returned by kvm_async_pf_gfn_slot() will be removed when an async pf gfn is going to be removed. However kvm_async_pf_gfn_slot() is not reliable in that it can return the last key it loops over even if the gfn is not found in the async gfn array. It should never happen, but it's still better to sanity check against that to make sure no unexpected gfn will be removed. Signed-off-by: Peter Xu Message-Id: <20200416155910.267514-1-peterx@redhat.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/x86/kvm/x86.c') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 8e28f21fb39b..370288fdedba 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10353,6 +10353,10 @@ static void kvm_del_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn) u32 i, j, k; i = j = kvm_async_pf_gfn_slot(vcpu, gfn); + + if (WARN_ON_ONCE(vcpu->arch.apf.gfns[i] != gfn)) + return; + while (true) { vcpu->arch.apf.gfns[i] = ~0; do { -- cgit v1.2.3