Re: [PATCH] iommu/quirk: disable shared EPT for Sandybridge and earlier processors.

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 26/11/15 08:45, Jan Beulich wrote:
>>>> On 25.11.15 at 16:58, <malcolm.crossley@citrix.com> wrote:
>> On 25/11/15 15:38, Jan Beulich wrote:
>>>>>> On 25.11.15 at 16:13, <andrew.cooper3@citrix.com> wrote:
>>>> On 25/11/15 10:49, Jan Beulich wrote:
>>>>> And finally I'm not fully convinced using CPU model info to deduce
>>>>> chipset behavior is entirely correct (albeit perhaps in practice it'll
>>>>> be fine except maybe when running Xen itself virtualized).
>>>> What else would you suggest? I can't think of any better identifying
>>>> information.
>>> Chipset IDs / revisions?
>> In this case the IOMMU is integrated into the Sandybridge-EP processor 
>> itself.
> Which doesn't preclude it to be identified via PCI device ID - after all
> there are dozens of processor integrated PCI devices. Looking at
> one of my systems,
>
> 00:05.0 System peripheral [0880]: Intel Corporation Sandy Bridge Address Map, VTd_Misc, System Management [8086:3c28] (rev 07)
> 80:05.0 System peripheral [0880]: Intel Corporation Sandy Bridge Address Map, VTd_Misc, System Management [8086:3c28] (rev 07)
>
> could be a candidate (we already key a quirk on this device in
> pci_vtd_quirk()).

These are fine for server variants, but not for desktop variants, both
of which we have seen in use.

~Andrew