Re: linux PVH broken in 3.16.0-rc7 (arch_gnttab_map_shared)

[David Vrabel <david.vrabel@citrix.com>]

On 06/08/14 22:23, Mukesh Rathor wrote:
> On Tue, 5 Aug 2014 12:00:12 +0100
> David Vrabel <david.vrabel@citrix.com> wrote:
> 
>> On 02/08/14 00:46, Mukesh Rathor wrote:
>>> Hi,
>>>
>>> Not sure if this already got reported, but it appears 
>>>
>>> commit b7dd0e3
>>> Author: David Vrabel <david.vrabel@citrix.com>
>>> Date:   Fri Jul 11 16:42:34 2014 +0100
>>>
>>>     x86/xen: safely map and unmap grant frames when in atomic
>>> context
>>>
>>> has broken boot of domU PVH. The reason being arch_gnttab_map_shared
>>> is getting called before gnttab_shared_vm_area gets initialized by
>>> arch_gnttab_init(). As the comment says,
>>>
>>> --->
>>> /* Call it _before_ __gnttab_init as we need to initialize the
>>>  *  * xen_auto_xlat_grant_frames first. */
>>> core_initcall(xen_pvh_gnttab_setup);
>>> <---
>>>
>>> we can't wait till arch_gnttab_init is called by __gnttab_init().
>>
>> Does this fix it?  I can't test it because the only box I have easily
>> available for testing is AMD.
>>
>> David
>>
> 
> Well, I don't see the crash, but guest hangs. My hunch is the pte
> entries that are populated are not correct, but I don't have time to
> look into it right now, so I'll let you debug.

If you don't care about working PVH support in Linux, someone else had
better step up and take care of it or its just going to remain broken
and I'll eventually have to consider removing it as unmaintained.

David