From: Pierre Morel <pmorel@linux.ibm.com>
To: David Hildenbrand <david@redhat.com>,
Tony Krowiak <akrowiak@linux.ibm.com>,
Tony Krowiak <akrowiak@linux.vnet.ibm.com>,
linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org
Cc: freude@de.ibm.com, schwidefsky@de.ibm.com,
heiko.carstens@de.ibm.com, borntraeger@de.ibm.com,
cohuck@redhat.com, kwankhede@nvidia.com,
bjsdjshi@linux.vnet.ibm.com, pbonzini@redhat.com,
alex.williamson@redhat.com, pmorel@linux.vnet.ibm.com,
alifm@linux.vnet.ibm.com, mjrosato@linux.vnet.ibm.com,
jjherne@linux.vnet.ibm.com, thuth@redhat.com,
pasic@linux.vnet.ibm.com, berrange@redhat.com,
fiuczy@linux.vnet.ibm.com, buendgen@de.ibm.com,
frankja@linux.ibm.com
Subject: Re: [PATCH v9 21/22] KVM: s390: CPU model support for AP virtualization
Date: Thu, 23 Aug 2018 10:26:05 +0200 [thread overview]
Message-ID: <933db512-fca1-a471-5e2d-b247cfc94fea@linux.ibm.com> (raw)
In-Reply-To: <38b87fc4-9344-70d8-4602-bf8e114769ef@redhat.com>
On 23/08/2018 09:48, David Hildenbrand wrote:
>>>>
>>> I really wonder if we should also export the APXA facility.
>>
>> Given this comment is made within the context of the
>> FACILITIES_KVM_CPUMODEL I might point out that APXA is not
>> indicated by a facilities bit. It is indicated by a bit in
>> the QCI control block returned from the PQAP(QCI)
>> instruction to indicate that APXA is installed on all CPUs.
>>
>>> We can probe and allow that CPU feature. However, we cannot disable it
>>> (as of now).
>>
>> Given this patch series implements passthrough devices,
>> the output of the PQAP(QCI) will always be from a real
>> device - i.e., there will be no way to disable it.
>>
>
> see below
>
>>>
>>> We have other CPU features where it is the same case (basically all
>>> subfunctions). See kvm_s390_get_processor_subfunc(). We probe them and
>>> export them, but support to disable them has never been implemented.
>>>
>>> On a high level, we could then e.g. deny to start a QEMU guest if APXA
>>> is available but has been disabled. (until we know that disabling it
>>> actually works - if ever).
>>>
>>> This helps to catch nasty migration bugs (e.g. APXA suddenly
>>> disappearing). Although unlikely, definitely possible.
>>
>> Migration of AP devices is not supported by this patch series, so this
>> should
>> not be an issue.
>
> Might not be a problem now, but could be later. As I said in a different
> reply, the CPU model in QEMU does not care about KVM.
>
> I want the QEMU CPU model and the KVM interfaces to be clean and future
> proof. That's why my opinion is to handle PQAP(QCI) just like all the
> other "feature blocks" we already have.
>
Don't you mix with the TAPQ instruction which has
a T bit to specify interception.
It indeed is not in the subfunction list even it
has a T bit to indicate interception.
TAPQ-t is indicated through the APFT facility.
We can use this bit as an indication of the presence
of APXA, the documentation mention that both are implemented together.
regards,
Pierre
--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany
next prev parent reply other threads:[~2018-08-23 8:26 UTC|newest]
Thread overview: 138+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-13 21:47 [PATCH v9 00/22] guest dedicated crypto adapters Tony Krowiak
2018-08-13 21:47 ` [PATCH v9 01/22] s390/zcrypt: Add ZAPQ inline function Tony Krowiak
2018-08-13 21:47 ` [PATCH v9 02/22] s390/zcrypt: Review inline assembler constraints Tony Krowiak
2018-08-13 21:48 ` [PATCH v9 03/22] s390/zcrypt: Show load of cards and queues in sysfs Tony Krowiak
2018-08-13 21:48 ` [PATCH v9 04/22] s390/zcrypt: Integrate ap_asm.h into include/asm/ap.h Tony Krowiak
2018-08-14 8:43 ` Cornelia Huck
2018-08-17 13:18 ` Tony Krowiak
2018-08-17 13:27 ` Cornelia Huck
2018-08-17 19:09 ` Tony Krowiak
2018-08-13 21:48 ` [PATCH v9 05/22] KVM: s390: vsie: simulate VCPU SIE entry/exit Tony Krowiak
2018-08-14 8:50 ` Cornelia Huck
2018-08-14 12:46 ` Tony Krowiak
2018-08-13 21:48 ` [PATCH v9 06/22] KVM: s390: introduce and use KVM_REQ_VSIE_RESTART Tony Krowiak
2018-08-13 21:48 ` [PATCH v9 07/22] KVM: s390: refactor crypto initialization Tony Krowiak
2018-08-20 16:41 ` David Hildenbrand
2018-08-20 20:33 ` Tony Krowiak
2018-08-20 20:41 ` David Hildenbrand
2018-08-21 13:29 ` Tony Krowiak
2018-08-13 21:48 ` [PATCH v9 08/22] s390: vfio-ap: base implementation of VFIO AP device driver Tony Krowiak
2018-08-14 10:42 ` Cornelia Huck
2018-08-14 23:30 ` Tony Krowiak
2018-08-13 21:48 ` [PATCH v9 09/22] s390: vfio-ap: register matrix device with VFIO mdev framework Tony Krowiak
2018-08-14 11:19 ` Cornelia Huck
2018-08-15 16:51 ` Tony Krowiak
2018-08-16 16:24 ` Tony Krowiak
2018-08-17 8:43 ` Cornelia Huck
2018-08-17 19:02 ` Tony Krowiak
2018-09-06 8:49 ` Pierre Morel
2018-09-10 13:38 ` Tony Krowiak
2018-09-10 21:58 ` Halil Pasic
2018-08-13 21:48 ` [PATCH v9 10/22] s390: vfio-ap: sysfs interfaces to configure adapters Tony Krowiak
2018-08-15 9:52 ` Cornelia Huck
2018-08-15 16:59 ` Tony Krowiak
2018-08-16 7:30 ` Cornelia Huck
2018-08-17 13:23 ` Tony Krowiak
2018-08-13 21:48 ` [PATCH v9 11/22] s390: vfio-ap: sysfs interfaces to configure domains Tony Krowiak
2018-08-15 12:05 ` Cornelia Huck
2018-08-15 17:00 ` Tony Krowiak
2018-08-13 21:48 ` [PATCH v9 12/22] s390: vfio-ap: sysfs interfaces to configure control domains Tony Krowiak
2018-08-20 14:23 ` Cornelia Huck
2018-08-20 16:43 ` Halil Pasic
2018-08-20 17:41 ` Tony Krowiak
2018-08-21 15:25 ` Cornelia Huck
2018-08-21 17:07 ` Tony Krowiak
2018-08-21 23:18 ` Halil Pasic
2018-08-22 9:42 ` Cornelia Huck
2018-08-22 10:43 ` Halil Pasic
2018-08-22 11:03 ` Pierre Morel
2018-08-22 15:11 ` Christian Borntraeger
2018-08-22 15:34 ` Pierre Morel
2018-08-22 15:48 ` Christian Borntraeger
2018-08-22 15:53 ` Pierre Morel
2018-08-22 17:11 ` Halil Pasic
2018-08-22 19:16 ` Tony Krowiak
2018-08-23 9:26 ` Halil Pasic
2018-08-23 10:41 ` Pierre Morel
2018-08-23 10:25 ` Cornelia Huck
2018-08-23 10:43 ` Pierre Morel
2018-08-23 11:31 ` Cornelia Huck
2018-08-23 11:44 ` Pierre Morel
2018-08-23 14:16 ` Tony Krowiak
2018-08-27 8:33 ` Cornelia Huck
2018-08-27 13:47 ` Tony Krowiak
2018-08-27 13:51 ` Cornelia Huck
2018-08-27 15:39 ` Halil Pasic
2018-09-10 13:27 ` Tony Krowiak
2018-08-22 15:18 ` Tony Krowiak
2018-08-22 14:31 ` Tony Krowiak
2018-08-13 21:48 ` [PATCH v9 13/22] s390: vfio-ap: sysfs interface to view matrix mdev matrix Tony Krowiak
2018-08-20 14:08 ` Cornelia Huck
2018-09-12 17:01 ` Tony Krowiak
2018-09-13 9:12 ` Halil Pasic
2018-08-13 21:48 ` [PATCH v9 14/22] KVM: s390: interfaces to clear CRYCB masks Tony Krowiak
2018-08-15 13:10 ` Cornelia Huck
2018-08-15 17:55 ` Tony Krowiak
2018-08-13 21:48 ` [PATCH v9 15/22] s390: vfio-ap: implement mediated device open callback Tony Krowiak
2018-08-15 16:08 ` Cornelia Huck
2018-08-15 18:21 ` Tony Krowiak
2018-08-13 21:48 ` [PATCH v9 16/22] s390: vfio-ap: implement VFIO_DEVICE_GET_INFO ioctl Tony Krowiak
2018-08-20 14:24 ` Cornelia Huck
2018-08-13 21:48 ` [PATCH v9 17/22] s390: vfio-ap: zeroize the AP queues Tony Krowiak
2018-08-15 16:24 ` Cornelia Huck
2018-08-15 20:36 ` Tony Krowiak
2018-08-17 9:34 ` Cornelia Huck
2018-08-13 21:48 ` [PATCH v9 18/22] s390: vfio-ap: implement VFIO_DEVICE_RESET ioctl Tony Krowiak
2018-08-15 16:38 ` Cornelia Huck
2018-08-15 21:05 ` Tony Krowiak
2018-08-17 9:38 ` Cornelia Huck
2018-08-17 19:03 ` Tony Krowiak
2018-08-13 21:48 ` [PATCH v9 19/22] KVM: s390: Clear Crypto Control Block when using vSIE Tony Krowiak
2018-08-13 21:48 ` [PATCH v9 20/22] KVM: s390: Handling of Cypto control block in VSIE Tony Krowiak
2018-08-21 8:30 ` David Hildenbrand
2018-08-13 21:48 ` [PATCH v9 21/22] KVM: s390: CPU model support for AP virtualization Tony Krowiak
2018-08-20 14:26 ` Cornelia Huck
2018-08-21 8:03 ` David Hildenbrand
2018-08-22 11:19 ` David Hildenbrand
2018-08-22 11:24 ` David Hildenbrand
2018-08-22 20:16 ` Tony Krowiak
2018-08-23 7:44 ` David Hildenbrand
2018-08-23 10:00 ` Halil Pasic
2018-08-23 10:28 ` David Hildenbrand
2018-08-23 11:10 ` Pierre Morel
2018-08-23 11:12 ` David Hildenbrand
2018-08-23 12:47 ` Pierre Morel
2018-08-23 13:22 ` Halil Pasic
2018-08-23 13:38 ` David Hildenbrand
2018-08-23 14:59 ` Pierre Morel
2018-08-23 17:35 ` Tony Krowiak
2018-08-23 17:40 ` David Hildenbrand
2018-08-24 10:28 ` Halil Pasic
2018-08-22 14:33 ` Pierre Morel
2018-08-22 15:04 ` David Hildenbrand
2018-08-22 15:50 ` Pierre Morel
2018-08-22 16:57 ` David Hildenbrand
2018-08-22 21:05 ` Tony Krowiak
2018-08-23 7:42 ` David Hildenbrand
2018-08-22 20:54 ` Tony Krowiak
2018-08-23 7:48 ` David Hildenbrand
2018-08-23 8:24 ` Cornelia Huck
2018-09-12 17:42 ` Tony Krowiak
2018-09-17 7:57 ` David Hildenbrand
2018-08-23 8:26 ` Pierre Morel [this message]
2018-08-13 21:48 ` [PATCH v9 22/22] s390: doc: detailed specifications " Tony Krowiak
2018-08-20 16:03 ` Cornelia Huck
2018-08-20 20:16 ` Tony Krowiak
2018-08-21 16:13 ` Cornelia Huck
2018-08-21 19:21 ` Tony Krowiak
2018-08-21 18:54 ` Halil Pasic
2018-08-22 7:38 ` Cornelia Huck
2018-08-21 9:00 ` Harald Freudenberger
2018-08-21 15:53 ` Cornelia Huck
2018-08-22 7:04 ` Harald Freudenberger
2018-08-22 10:09 ` Cornelia Huck
2018-08-22 10:13 ` Harald Freudenberger
2018-08-22 10:45 ` Halil Pasic
2018-08-22 10:19 ` [PATCH v9 00/22] guest dedicated crypto adapters Cornelia Huck
2018-08-22 10:58 ` Pierre Morel
2018-08-22 18:59 ` Tony Krowiak
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