Re: [PATCH 4/4] kvm-s390: onereg for timer related registers

[Christian Borntraeger <borntraeger@de.ibm.com>]

On 05/06/12 14:42, Alexander Graf wrote:
> 
> On 15.05.2012, at 14:15, Christian Borntraeger wrote:
> 
>> From: "Jason J. herne" <jjherne@us.ibm.com>
>>
>> Enhance the KVM ONE_REG capability within S390 to allow
>> getting/setting the following special cpu registers: clock comparator
>> and the cpu timer. These are needed for migration.
>>
>> Signed-off-by: Jason J. herne <jjherne@us.ibm.com>
>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> 
> Any other registers we need to expose to user space while we're at it? :)

I hope not. Life guest relocation prototyping indicates that we have at least
the subset that allows a linux guest to continue.

We might need a way for userspace to influence the output of the store
system information and store facility list instruction. Dont know, maybe
we could use ONEREG even for that purpose. Its on my todo list, but there
are too many other things to tidy up.

Since this would be interface/ABI I dont want to rush without really
understanding what I need for those instruction.

Christian