Re: [PATCH 2/2] KVM MMU: fix race in invlpg code

[Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>]

Avi Kivity wrote:

>>       spin_lock(&vcpu->kvm->mmu_lock);
>> +    index = kvm_page_table_hashfn(gfn);
>> +    bucket =&vcpu->kvm->arch.mmu_page_hash[index];
>> +    hlist_for_each_entry_safe(s, node, tmp, bucket, hash_link)
>> +        if (s == sp) {
>> +            if (s->gfn == gfn&&  s->role.word == role.word)
>> +                live = true;
>> +            break;
>> +        }
>> +
>> +    if (!live)
>> +        goto unlock_exit;
>> +
>>    
> 
> Did you try the root_count method?  I think it's cleaner.

Avi, Thanks for your idea.

I have considered this method, but i'm not sure when it's the good time
to real free this page, and i think we also need a way to synchronize the
real free path and this path. Do you have any comment for it :-(

Xiao