Re: [Xen-devel] Xen-unstable: Bisected Host boot failure on AMD Phenom

[Sander Eikelenboom <linux@xxxxxxxxxxxxxx>]

On 02/03/17 19:29, Andrew Cooper wrote:
> On 02/03/17 18:25, Sander Eikelenboom wrote:
>> On 02/03/17 18:38, Andrew Cooper wrote:
>>> On 02/03/17 17:29, Sander Eikelenboom wrote:
>>>> On 02/03/17 15:55, Andrew Cooper wrote:
>>>>> On 02/03/17 14:42, Sander Eikelenboom wrote:
>>>>>> Hi Andrew / Jan,
>>>>>>
>>>>>> While testing current xen-unstable staging i ran into my host rebooting 
>>>>>> in early kernel boot. 
>>>>>> Bisection has turned up:
>>>>>>     5cecf60f439e828f4bc0d2a368ced9a73b130cb7 is the first bad commit
>>>>>>     Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
>>>>>>     Date:   Fri Feb 17 17:10:50 2017 +0000
>>>>>>
>>>>>>     x86/cpuid: Handle leaf 0x1 in guest_cpuid()
>>>>>>
>>>>>> Hardware is a AMD phenom x6.
>>>>>> Below is the output of serial console of a failed boot.
>>>>> Hmm.  Sorry for breaking this (although my AMD servers are booting fine).
>>>> No problem, it is the staging branch of the unstable tree anyway ;-)
>>>>
>>>>> It is unfortunately not entirely obvious what Linux is objecting to, and
>>>>> must be related to something visible in the emulated view.
>>>>>
>>>>> Does this delta make any difference?
>>>> Yes it does, boots fine with this patch applied, thanks !
>>> That is bad though. :s
>>>
>>> It means that something in dom0 has an aversion to my attempt to lie
>>> less about the topology.
>>>
>>> Do you mind checking whether
>>>
>>> res->b = cpuid_ebx(0x1) & 0xff00ffffu;
>>>
>>> causes is to break again?
>> Used that in the is_hardware_domain() case and it boots fine.
> 
> Hmm - curious.  I am now even more confused.
> 
> What about this?
> 
> res->b = cpuid_ebx(0x1) & 0x00ffffffu;
> 
> It will leave the APIC_ID field zeroed rather than feeding v->vcpu_id
> back into it.

Also boots fine.

--
Sander
> 
> ~Andrew
> 


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