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

[Avi Kivity]

On 06/16/2010 10:59 AM, Andi Kleen wrote:
> On Tue, Jun 15, 2010 at 02:22:06PM +0300, Avi Kivity wrote:
>    
> > Too much duplication.  How about putting the tail end of the function in a
> > common helper (with an inatomic flag)?
> >
> > btw, is_hwpoison_address() is racy.  While it looks up the address, some
> > other task can unmap the page tables under us.
> >      
> Where is is_hwpoison_address() coming from? I can't find it anywhere.
>
>    

kvm.git master mm/memory-failure.c (19564281fe).

> Anyways hwpoison will not remove the page as long as there
> is a reference to it, so as long as you get the reference
> race free against another task you're ok. Of course there might
> be always an error in between and the hardware may poison
> the data, but we don't try to handle all kernel errors.
>    

The page is fine, the page tables are not.  Another task can munmap() 
the thing while is_hwpoison_address() is running.

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

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