Re: [Xen-devel] RFC: xencomm in common

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

Hi Tristan.
Since I looked the patch very roughly, I might be wrong and parania though.

xencomm_copy_from_guest(), xencomm_copy_to_guest() converts
address, then acessses a page.
The Xen/IA64 P2M table is lockless so that the page can be freed 
by another cpu and used for other purpose at the same time.
(Actually such a guest behaviour doesn't make sense, but possible.)
get_page()/put_page() are necessary to prevent such a situation.
Actually Xen/IA64's vcpu_get_domain_bundle() and
efi_translate_domain_addr() do it.


On Wed, Aug 23, 2006 at 10:15:41AM +0200, Tristan Gingold wrote:
> Le Lundi 21 Août 2006 11:41, Keir Fraser a écrit :
> > On 21/8/06 10:20 am, "Tristan Gingold" <Tristan.Gingold@xxxxxxxx> wrote:
> > >> Fine in principle. Specific comments:
> > >>  * powerpc should be cleaned up at the same time to use the common
> > >> infrastructure. I don't want duplicated code hanging around in
> > >> arch/powerpc
> > >
> > > I have attached a blindly-made patch again powerpc files.
> > > If ppc people could check this, I'd be happy.
> > >
> > >>  * The code you add to common/ should obey the coding style of other
> > >> files in that directory
> > >>  * Arguably we should have an asm-generic for the xencomm guest-access
> > >> macros. That's a Linux-ism which I think fits well in this particular
> > >> case.
> > >
> > > Taken into account in this updated patch.
> >
> > Looks better. I assume you'll resend with signed-off-by when you want these
> > applied.
> Hi,
> 
> here are the signed-off-by patches for xen.
> I took the liberty to add Hollis Blanchard in signed-off-by of the first 
> patch 
> because he is the primary author of these files.
> 
> I don't know wether or not these patches should be put off beacause of the 
> freeze, but they are a no-op for x86.
> 
> Tristan.



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-- 
yamahata

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