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

Gleb Natapov
2013-10-24T09:32:40Z

On Thu, Oct 24, 2013 at 05:24:12PM +0800, Xiao Guangrong wrote:
> 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.
Ah, I haven't got 12/15 and git am did not complain :(

--
Gleb.