Re: [PATCH 4/4] PF: Async page fault support on s390

From: Paolo Bonzini
Date: Thu Jul 18 2013 - 09:57:54 EST


Il 11/07/2013 12:41, Christian Borntraeger ha scritto:
> On 11/07/13 11:04, Gleb Natapov wrote:
>> On Wed, Jul 10, 2013 at 02:59:55PM +0200, Dominik Dingel wrote:
>>> This patch enables async page faults for s390 kvm guests.
>>> It provides the userspace API to enable, disable or get the status of this
>>> feature. Also it includes the diagnose code, called by the guest to enable
>>> async page faults.
>>>
>>> The async page faults will use an already existing guest interface for this
>>> purpose, as described in "CP Programming Services (SC24-6084)".
>>>
>>> Signed-off-by: Dominik Dingel <dingel@xxxxxxxxxxxxxxxxxx>
>> Christian, looks good now?
>
> Looks good, but I just had a discussion with Dominik about several other cases
> (guest driven reboot, qemu driven reboot, life migration). This patch should
> allow all these cases (independent from this patch we need an ioctl to flush the
> list of pending interrupts to do so, but reboot is currently broken in that
> regard anyway - patch is currently being looked at)
>
> We are currently discussion if we should get rid of the APF_STATUS and let
> the kernel wait for outstanding page faults before returning from KVM_RUN
> or if we go with this patch and let userspace wait for completion.
>
> Will discuss this with Dominik, Conny and Alex. So lets defer that till next
> week, ok?

Let us know if we should wait for a v5. :)

Paolo

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