Re: [PATCH 2/2] vhost: re-introducing metadata acceleration through kernel virtual address

[Jason Wang]

On 2019/9/9 äå12:45, Michael S. Tsirkin wrote:
> > > Since idx can be speculated, I guess we need array_index_nospec here?
> > So we have
> >
> > ACQUIRE(mmu_lock)
> >
> > get idx
> >
> > RELEASE(mmu_lock)
> >
> > ACQUIRE(mmu_lock)
> >
> > read array[idx]
> >
> > RELEASE(mmu_lock)
> >
> > Then I think idx can't be speculated consider we've passed RELEASE +
> > ACQUIRE?
> I don't think memory barriers have anything to do with speculation,
> they are architectural.

Oh right. Let me add array_index_nospec() in next version.

Thanks