Re: [PATCH for-4.6] xen/arm: vgic-v2: Map the GIC virtual CPU interface with the correct size

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

Hi Ian,

On 21/09/15 12:54, Ian Campbell wrote:
> On Fri, 2015-09-18 at 09:53 +0100, Ian Campbell wrote:
>> On Thu, 2015-09-17 at 19:00 +0100, Julien Grall wrote:
>>> On GICv2, the GIC virtual CPU interface is at minimum 8KB. Due some to
>>> some necessary quirk for GIC using 64KB stride, we are mapping the
>>> region in 2 time.
>>> The first mapping is 4KB and the second one is 8KB, i.e 12KB in total.
>>> Although the minimum supported size (and widely used) is 8KB. This
>>> means
>>> that we are mapping 4KB more to any guest using GICv2.
>>>
>>> While this looks scary at first glance, the GIC virtual CPU interface
>>> is
>>> most frequently at the end the GIC I/O region. So we will most likely
>>> map an an unused I/O region or a mirrored version of GICV for platform
>>> using 64KB stride.
>>>
>>> Nonetheless, fix the second mapping to only map 4KB.
>>>
>>> Signed-off-by: Julien Grall <julien.grall@citrix.com>
>>
>> Acked-by: Ian Campbell <ian.campbell@citrix.com>
>>
>>> ---
>>>
>>> This is a candidate for Xen 4.6 and backport to Xen 4.5.
>>
>> I concur and with Wei not being around I shall plan to apply later today
>> unless there are objections.
> 
> I got distracted. Now applied to staging and staging-4.6 now and noted for
> later application to 4.5

It won't apply cleanly for Xen 4.5, this code was living in the gic
driver. I will send a backport patch for it.

Regards,

-- 
Julien Grall