KVM: fix searching async gfn in kvm_async_pf_gfn_slot

Don't search later slots if the slot is empty
Acked-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

arch/x86/kvm/x86.c

@@ -6209,8 +6209,8 @@ static u32 kvm_async_pf_gfn_slot(struct kvm_vcpu *vcpu, gfn_t gfn)
 	u32 key = kvm_async_pf_hash_fn(gfn);
 
 	for (i = 0; i < roundup_pow_of_two(ASYNC_PF_PER_VCPU) &&
-		     (vcpu->arch.apf.gfns[key] != gfn ||
-		      vcpu->arch.apf.gfns[key] == ~0); i++)
+		     (vcpu->arch.apf.gfns[key] != gfn &&
+		      vcpu->arch.apf.gfns[key] != ~0); i++)
 		key = kvm_async_pf_next_probe(key);
 
 	return key;