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Date: Thu, 18 Jul 2013 16:12:24 +0200
From: Christian Borntraeger <borntraeger@de.ibm.com>
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To: Paolo Bonzini <pbonzini@redhat.com>
CC: Gleb Natapov <gleb@redhat.com>, Dominik Dingel <dingel@linux.vnet.ibm.com>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Cornelia Huck <cornelia.huck@de.ibm.com>,
        Xiantao Zhang <xiantao.zhang@intel.com>,
        Alexander Graf <agraf@suse.de>,
        Christoffer Dall <christoffer.dall@linaro.org>,
        Marc Zyngier <marc.zyngier@arm.com>,
        Ralf Baechle <ralf@linux-mips.org>, kvm@vger.kernel.org,
        linux-s390@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/4] PF: Async page fault support on s390
References: <1373461195-27628-1-git-send-email-dingel@linux.vnet.ibm.com> <1373461195-27628-5-git-send-email-dingel@linux.vnet.ibm.com> <20130711090411.GA8575@redhat.com> <51DE8BE1.8000902@de.ibm.com> <51E7F440.2010600@redhat.com>
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On 18/07/13 15:57, Paolo Bonzini wrote:
> 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@linux.vnet.ibm.com>
>>> 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. :)

Yes, there will be a v5