Re: [PATCH 3/6] KVM: MMU: introduce gfn_to_page_atomic() and gfn_to_pfn_atomic()

[Avi Kivity]

On 06/16/2010 11:49 AM, Andi Kleen wrote:
> > The page is fine, the page tables are not.  Another task can munmap() the
> > thing while is_hwpoison_address() is running.
> >      
> Ok  that boils down to me not seeing that source.
>
> If it accesses the page tables yes then it's racy. But whoever
> looked up the page tables in the first place should have
> returned an -EFAULT. There's no useful address attached
> to poison.
>    

We need to distinguish between genuine -EFAULT and poisoned address.

That's why I suggested get_user_pages_ptes_fast.  You can return page = 
NULL (-EFAULT) and the pte in the same go.  No race, and useful for 
other cases.

--
error compiling committee.c: too many arguments to function

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