[Oneiric] Temporary Xen HVM work-around
Stefan Bader
stefan.bader at canonical.com
Thu Sep 1 14:37:03 UTC 2011
On 01.09.2011 16:25, Tim Gardner wrote:
> On 09/01/2011 08:17 AM, Stefan Bader wrote:
>> On 01.09.2011 16:12, Tim Gardner wrote:
>>> On 09/01/2011 07:56 AM, Stefan Bader wrote:
>>>> On 01.09.2011 15:54, Stefan Bader wrote:
>>>>> On 01.09.2011 15:39, Tim Gardner wrote:
>>>>>> On 09/01/2011 07:23 AM, Stefan Bader wrote:
>>>>>>> I would like to propose the following SAUCE patch for Oneiric. Without
>>>>>>> this the Oneiric kernel fails to boot in HVM mode from a Xen 4.1.1 or
>>>>>>> newer hypervisor (which we ship in Oneiric).
>>>>>>>
>>>>>>> It should be only temporary, but I am not sure we find a proper solution
>>>>>>> within the time before final freeze and I rather would see the released
>>>>>>> kernel at least booting.
>>>>>>>
>>>>>>> Changes only affect code paths used when booting in HVM mode under Xen,
>>>>>>> so there should be no other impact.
>>>>>>>
>>>>>>> -Stefan
>>>>>>>
>>>>>>
>>>>>> Can you think of any possible impact this might have for an LTS backport ?
>>>>>> We're
>>>>>> not doing anything for -ec2 backports, right ?
>>>>>>
>>>>>> rtg
>>>>>
>>>>> We do not have an LTS backport for EC2. Of course people can an do run the
>>>>> normal (generic-pae for i386, amd64 should be ok with any flavour) LTS
>>>>> backport
>>>>> kernel in Lucid installations. If the hyperviser is older that 4.1.1 this
>>>>> has no
>>>>> impact at all. And for the other ones it would cause the same issue.
>>>>>
>>>>> -Stefan
>>>>>
>>>> Of course I meant "under Xen" somewhere above...
>>>>
>>>
>>> So if someone was running Lucid user space as a Xen domU guest on a hypervisor
>>> older then 4.1.1, then installing the Oneiric LTS backport would normally work,
>>> right? Will this patch impact that ?
>>>
>>> rtg
>>
>> No, hypervisors older than 4.1.1 will not offer the vector callback feature,
>> which in turn prevents pv spinlocks (as well as pv IPIs) from being tried to
>> enable by a 3.0 kernel.
>> So those work as before.
>>
>> -Stefan
>
> Uh, I think what you just said is that Oneiric will work fine on hypervisors
> prior to 4.1.1 regardless of whether this patch is applied.
>
> rtg
Yes.
-Stefan
More information about the kernel-team
mailing list