Re: [PATCH] memory: don't suppress P2M update in populate_physmap()

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

On 06/20/2017 02:03 PM, Jan Beulich wrote:
>>>> On 20.06.17 at 14:51, <julien.grall@arm.com> wrote:
>> On 06/20/2017 01:40 PM, Andrew Cooper wrote:
>>> On 20/06/17 13:39, Julien Grall wrote:
>>>> On 06/20/2017 09:37 AM, Andrew Cooper wrote:
>>>>> On 20/06/17 07:19, Jan Beulich wrote:
>>>>>> Commit d18627583d ("memory: don't hand MFN info to translated guests")
>>>>>> wrongly added a null-handle check there - just like stated in its
>>>>>> description for memory_exchange(), the array is also an input for
>>>>>> populate_physmap() (and hence can't reasonably be null). I have no idea
>>>>>> how I've managed to overlook this.
>>>>>>
>>>>>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>>>>>
>>>>> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
>>>>
>>>> Am I correct that this is not a bug and only a pointless check?
>>>
>>> This is a partial reversion of d18627583d and needs to be included in
>>> 4.9, to avoid a regression.
>>
>> Would you mind to explain why this would introduce regression? AFAICT
>> the check is just redundant, so keeping it is not that bad.
> 
> Afaict there would be a regression only if someone invoked the
> hypercall with a null handle (but having valid data at address zero).
> Still I agree with Andrew that we'd better include this in 4.9.

Hmmm. It didn't occur to me that someone would put valid data at address 
zero.

Release-acked-by: Julien Grall <julien.grall@arm.com>

Cheers,

-- 
Julien Grall

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel