Re: 2.6.35-rc1 regression with pvclock and smp guests

Zachary Amsden
2010-10-11T20:47:25Z

On 10/08/2010 10:59 PM, Arjan Koers wrote:
> On 2010-10-09 08:29, Michael Tokarev wrote:
> ...
>
>> The result is that no released linux kernel boots
>> in smp in kvm, which is a linux virtual machine.
>> That's irony, isn't it?
>>
>> I wonder how distributions (which are almost all based
>> on 2.6.32 nowadays) will deal with the issue.. ;)
>>
> It looks like Debian solved it on their 2.6.32 guest by
> reverting the commit that makes it hang:
> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=588426
>

That's not a wise choice, the commit is needed to prevent clocks going
backwards. It then caused some fallout issues with clobbers, which I
believe hpa fixed, but there were several rounds of it.

Glauber, perhaps, has a better idea of what patches are needed for the
host side kvmclock. I've mostly been working on the server side.

To solve the wider range of problems, distributions converging on 2.6.32
will need all of the fixes backported, both server and host.