Re: [Xen-devel] [PATCH v2 0/2] Support of RO MMCFG access for PVH/HVMlite dom0s

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 18.12.15 at 15:30, <boris.ostrovsky@xxxxxxxxxx> wrote:
> On 12/18/2015 09:16 AM, Jan Beulich wrote:
>>>>> On 18.12.15 at 14:53, <boris.ostrovsky@xxxxxxxxxx> wrote:
>>> On 12/18/2015 08:02 AM, Andrew Cooper wrote:
>>>> On 18/12/15 10:11, Jan Beulich wrote:
>>>>>>>> On 17.12.15 at 21:22, <boris.ostrovsky@xxxxxxxxxx> wrote:
>>>>>> * Left non-MMCFG RO accesses unhandled (we havent't encountered those
>>> accesses
>>>>>>     yet with PVH dom0 and it's probably better to fault on them and
>>> investigate
>>>>>>     whether they are guest's issues).
>>>>> I seriously question this being a good approach,
>>>> I concur.  All accesses should be terminated somehow, even if this is
>>>> the hypervisor dropping writes and completing reads with ~0's.
>>>>
>>>> This is the expected behaviour from the x86 architecture.
>>> OK, I'll add that in.
>>>
>>> To answer Jan's question, I did try 'vga=keep' and that worked fine.
>> Interesting. Does your system not load/use a DRM driver for the
>> card? Or is the driver so minimalistic that no extended config
>> space write ever occurs?
> 
> It does load the driver:
> 
> 0b:00.0 VGA compatible controller: Matrox Graphics, Inc. MGA G200e 
> [Pilot] ServerEngines (SEP1) (rev 04)
>      Subsystem: Intel Corporation Device 0101
>      Kernel driver in use: mgag200
> ..
> root@ovs104> lsmod | grep mgag
> mgag200                45056  1
> ttm                    90112  1 mgag200
> drm_kms_helper        122880  1 mgag200
> drm                   335872  4 mgag200,ttm,drm_kms_helper
> i2c_algo_bit           16384  2 igb,mgag200
> 
> but I don't know what it does to the config space. I configured my 
> kernel for a fairly minimal configuration so perhaps I disabled 
> something that limits what the driver does.

For the MGA driver I'm not really surprised; I expected you would
be using one of the more common ones (radeon, nouveau, or i915).

Jan


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