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

[Julien Grall <julien.grall@citrix.com>]

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@citrix.com>
>>>
>>> ---
>>> Cc: Ian Jackson <ian.jackson@eu.citrix.com>
>>> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
>>> Cc: Ian Campbell <ian.campbell@citrix.com>
>>> Cc: Wei Liu <wei.liu2@citrix.com>
>>>
>>
>> Acked-by: Wei Liu <wei.liu2@citrix.com>
>
> Acked-by: Ian Campbell <ian.campbell@citrix.com>
>
>> 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