Re: [PATCH v3 13/15] KVM: MMU: locklessly write-protect the page

Xiao Guangrong
2013-10-24T09:35:11Z

On 10/24/2013 05:17 PM, Gleb Natapov wrote:

>>
>> -/**
>> - * kvm_mmu_write_protect_pt_masked - write protect selected PT level pages
>> +static void __rmap_write_protect_lockless(u64 *sptep)
>> +{
>> + u64 spte;
>> +
>> +retry:
>> + /*
>> + * Note we may partly read the sptep on 32bit host, however, we
>> + * allow this case because:
>> + * - we do not access the page got from the sptep.
>> + * - cmpxchg64 can detect that case and avoid setting a wrong value
>> + * to the sptep.
>> + */
>> + spte = *rcu_dereference(sptep);
>> + if (unlikely(!is_last_spte(spte) || !is_writable_pte(spte)))
> is_last_spte gets two parameters.

In patch [PATCH v3 12/15] KVM: MMU: check last spte with unawareness of mapping level,
we have removed the 'level' from the parameter list.