Re: AMD IOMMU disabled - No Perdev Intremap

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

On 06/10/2013 15:38, Sander Eikelenboom wrote:
> Sunday, October 6, 2013, 3:09:54 PM, you wrote:
>
>> On 10/06/2013 02:58 PM, Andrew Cooper wrote:
>>> On 06/10/2013 13:56, Ferdinand Nölscher wrote:
>>>> Hi Sander,
>>>>
>>>> Thanks for your reply.
>>>>
>>>> On 10/06/2013 02:10 PM, Sander Eikelenboom wrote:
>>>>> Sunday, October 6, 2013, 1:36:33 PM, you wrote:
>>>>>
>>>>>> Hi!
>>>>>>> From other people posting to this list, I know that there has
>>>>>>> been a
>>>>>> bug related to the issue described in Xen Security Advisory 36
>>>>>> that disables iommu for some AMD users like me.
>>>>> What motherboard do you have ?
>>>> I have an ASUS M5A99X EVO Rev 1.01
>>>>
>>>>
>>>>> It depends if it's the north or southbridge ioapic but try using
>>>>> the new xen boot parameter: (add it to the xen.gz line in grub)
>>>>>
>>>>> ivrs_ioapic[0]=00:14.0
>>>>>
>>>>> or
>>>>>
>>>>> ivrs_ioapic[0]=00:00.1
>>>> I tried both, it still fails to enable i/o virtualisation.
>>> Can you post a full xl dmesg, booting with iommu=debug,verbose as well?
>>>
>>> ~Andrew
>>>
>>>
> Ah it seems i got the id's mixed up :-)
>
> ivrs_ioapic[9]=00:00.1 ivrs_ioapic[10]=00:14.0
>
> Should do it i guess .. or should the ioapic handle be in hex .. (then the last should be ivrs_ioapic[a]=00:14.0 )
>
> --
> Sander
>
>

parse_ivrs_ioapic uses simple_strtoul(..., 0), so decimal or 0xa is
fine, but 'a' on its own wont be.

Seeing as I clearly don't understand how this fix is working, do you
mind explaining (as you seem to have worked out the problem) ?

~Andrew