Re: [PATCH/RFC 4/5] s390x/kvm: test whether a cpu is STOPPED when checking "has_work"

Alexander Graf
2014-07-28T13:49:09Z

On 10.07.14 15:10, Christian Borntraeger wrote:
> From: David Hildenbrand <dahi@linux.vnet.ibm.com>
>
> If a cpu is stopped, it must never be allowed to run and no interrupt may wake it
> up. A cpu also has to be unhalted if it is halted and has work to do - this
> scenario wasn't hit in kvm case yet, as only "disabled wait" is processed within
> QEMU.
>
> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

This looks like it's something that generic infrastructure should take
care of, no? How does this work for the other archs? They always get an
interrupt on the transition between !has_work -> has_work. Why don't we
get one for s390x?

Alex