Re: [Xen-devel] [PATCH for-4.6] tools/libxc: linux: Don't use getpagesize() when unmapping the grants

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Ian,

On 11/08/2015 13:48, Ian Campbell wrote:
> On Fri, 2015-08-07 at 22:45 +0100, Wei Liu wrote:
> > On Fri, Aug 07, 2015 at 07:53:55PM +0100, Julien Grall wrote:
> > > The grants are based on the Xen granularity (i.e 4KB). While the
> > > function
> > > to map grants for Linux (linux_gnttab_grant_map) is using the correct
> > > size (XC_PAGE_SIZE), the unmap one (linux_gnttab_munmap) is using
> > > getpagesize().
> > >
> > > On domain using a page granularity different than Xen (this is the case
> > > for AARCH64 guest using 64KB page), the unmap will be called with the
> > > wrong size.
> > >
> > > Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> > >
> > > ---
> > > Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
> > > Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> > > Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
> > > Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
> > Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
>
> > I think this is a bug fix and should be applied for 4.6.
> Agreed.
>
> WRT to backports for 4.5 I'd appreciate being given a full list of required
> fixes once everything is in place and working for 4.6/devbranch rather than
> my tracking it piecemeal.
I have a working branch with Xen tools running on 64KB, and I didn't 
expected to find another problem.
I spotted this one by reading the code and see inconsistency between the 
mmap and the mmunmap. And I'm sure I haven't spot all the things because 
testing every configuration to see if 64KB guest are working is a huge work.
Anyway, I will send a mail with all the patch to backport.

Regards,

--
Julien Grall

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