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From: Cornelia Huck <cohuck@redhat.com>
To: Tony Krowiak <akrowiak@linux.ibm.com>
Cc: Pierre Morel <pmorel@linux.ibm.com>,
	Tony Krowiak <akrowiak@linux.vnet.ibm.com>,
	linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, freude@de.ibm.com, schwidefsky@de.ibm.com,
	heiko.carstens@de.ibm.com, borntraeger@de.ibm.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 v8 17/22] s390: vfio-ap: zeroize the AP queues.
Date: Mon, 13 Aug 2018 08:57:55 +0200
Message-ID: <20180813085755.6ad962fb.cohuck@redhat.com> (raw)
In-Reply-To: <14983b58-f53b-8bd9-179e-29b9a69c21d8@linux.ibm.com>

On Fri, 10 Aug 2018 12:24:47 -0400
Tony Krowiak <akrowiak@linux.ibm.com> wrote:

> On 08/10/2018 07:16 AM, Cornelia Huck wrote:
> > On Fri, 10 Aug 2018 12:49:08 +0200
> > Pierre Morel <pmorel@linux.ibm.com> wrote:
> >  
> >> On 10/08/2018 11:14, Cornelia Huck wrote:  
> >>> On Wed,  8 Aug 2018 10:44:27 -0400
> >>> Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote:
> >>>     
> >>>> From: Tony Krowiak <akrowiak@linux.ibm.com>
> >>>>
> >>>> Let's call PAPQ(ZAPQ) to zeroize a queue:
> >>>>
> >>>> * For each queue configured for a mediated matrix device
> >>>>     when it is released.
> >>>>
> >>>> Zeroizing a queue resets the queue, clears all pending
> >>>> messages for the queue entries and disables adapter interruptions
> >>>> associated with the queue.
> >>>>
> >>>> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
> >>>> Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
> >>>> Tested-by: Michael Mueller <mimu@linux.ibm.com>
> >>>> Tested-by: Farhan Ali <alifm@linux.ibm.com>
> >>>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> >>>> ---
> >>>>    drivers/s390/crypto/vfio_ap_ops.c     |   29 ++++++++++++++++++++++++++++-
> >>>>    drivers/s390/crypto/vfio_ap_private.h |   25 +++++++++++++++++++++++++
> >>>>    2 files changed, 53 insertions(+), 1 deletions(-)
> >>>>
> >>>> @@ -788,7 +812,10 @@ static void vfio_ap_mdev_release(struct mdev_device *mdev)
> >>>>    {
> >>>>    	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> >>>>    
> >>>> -	kvm_arch_crypto_clear_masks(matrix_mdev->kvm);
> >>>> +	if (matrix_mdev->kvm)
> >>>> +		kvm_arch_crypto_clear_masks(matrix_mdev->kvm);  
> >>> Confused. Why is the check for matrix_mdev->kvm added here?  
> >> When using the KVM notifier we can get two notifications:  
> >> -> KVM is here / is comming
> >> -> KVM is not here / disappearing  
> >>
> >> In the first case we initialize matrix_mdev->kvm with a pointer to KVM
> >> In the second case we nullify the pointer.
> >>
> >> During the open of the mediated device, the guest should have been started
> >> or we refuse to start.
> >>
> >> During the close of the mediated device, the guest should be there, but
> >> we have no certitude that the guest did not disappear before the VFIO
> >> file being closed.
> >> Since we do not allow multiple guests using the same mediated device
> >> this case should not happen with QEMU. But I am not sure that
> >> a rogue user program could not stop KVM before closing the VFIO
> >> mediated device.  
> > I'm not sure why the check is introduced in this patch, though. But
> > maybe I just need weekend :)  
> 
> Good catch, it belongs in patch 15 where the function is introduced.
> Is that the only reason for your objection?

Yes, this is what confused me. Moving this to patch 15 sounds like a
good idea :)

> 
> >  
> >> Maybe Alex can confirm this point, if not we can remove the test.  
> 
> 


  reply index

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-08 14:44 [PATCH v8 00/22] vfio-ap: guest dedicated crypto adapters Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 01/22] s390/zcrypt: Add ZAPQ inline function Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 02/22] s390/zcrypt: Review inline assembler constraints Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 03/22] s390/zcrypt: Show load of cards and queues in sysfs Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 04/22] s390/zcrypt: Integrate ap_asm.h into include/asm/ap.h Tony Krowiak
2018-08-09  9:06   ` Cornelia Huck
2018-08-09  9:17     ` Harald Freudenberger
2018-08-09 13:45       ` Harald Freudenberger
2018-08-09 16:06       ` Tony Krowiak
2018-08-10  8:49         ` Cornelia Huck
2018-08-10  9:37           ` Harald Freudenberger
2018-08-10 15:53             ` Tony Krowiak
2018-08-10 15:50           ` Tony Krowiak
2018-08-09 15:18     ` Tony Krowiak
2018-08-09 15:43       ` Heiko Carstens
2018-08-09 16:55         ` Tony Krowiak
2018-08-13  9:24     ` Harald Freudenberger
2018-08-13  9:34       ` Cornelia Huck
2018-08-08 14:44 ` [PATCH v8 05/22] KVM: s390: vsie: simulate VCPU SIE entry/exit Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 06/22] KVM: s390: introduce and use KVM_REQ_VSIE_RESTART Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 07/22] KVM: s390: refactor crypto initialization Tony Krowiak
2018-08-09  5:58   ` Janosch Frank
2018-08-10 16:13     ` Tony Krowiak
2018-08-09  8:25   ` David Hildenbrand
2018-08-09 19:54     ` Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 08/22] s390: vfio-ap: base implementation of VFIO AP device driver Tony Krowiak
2018-08-09 10:12   ` Cornelia Huck
2018-08-08 14:44 ` [PATCH v8 09/22] s390: vfio-ap: register matrix device with VFIO mdev framework Tony Krowiak
2018-08-09 11:06   ` Cornelia Huck
2018-08-09 16:27     ` Pierre Morel
2018-08-10  8:59       ` Cornelia Huck
2018-08-08 14:44 ` [PATCH v8 10/22] s390: vfio-ap: sysfs interfaces to configure adapters Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 11/22] s390: vfio-ap: sysfs interfaces to configure domains Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 12/22] s390: vfio-ap: sysfs interfaces to configure control domains Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 13/22] s390: vfio-ap: sysfs interface to view matrix mdev matrix Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 14/22] KVM: s390: interfaces to clear CRYCB masks Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 15/22] s390: vfio-ap: implement mediated device open callback Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 16/22] s390: vfio-ap: implement VFIO_DEVICE_GET_INFO ioctl Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 17/22] s390: vfio-ap: zeroize the AP queues Tony Krowiak
2018-08-10  9:14   ` Cornelia Huck
2018-08-10 10:49     ` Pierre Morel
2018-08-10 11:16       ` Cornelia Huck
2018-08-10 16:24         ` Tony Krowiak
2018-08-13  6:57           ` Cornelia Huck [this message]
2018-08-08 14:44 ` [PATCH v8 18/22] s390: vfio-ap: implement VFIO_DEVICE_RESET ioctl Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 19/22] KVM: s390: Clear Crypto Control Block when using vSIE Tony Krowiak
2018-08-09  8:10   ` David Hildenbrand
2018-08-09  8:50     ` Pierre Morel
2018-08-09  8:57     ` Pierre Morel
2018-08-08 14:44 ` [PATCH v8 20/22] KVM: s390: Handling of Cypto control block in VSIE Tony Krowiak
2018-08-09  6:20   ` Janosch Frank
2018-08-09  7:33     ` Pierre Morel
2018-08-08 14:44 ` [PATCH v8 21/22] KVM: s390: CPU model support for AP virtualization Tony Krowiak
2018-08-09  8:17   ` David Hildenbrand
2018-08-09  8:34     ` Harald Freudenberger
2018-08-09 20:27     ` Tony Krowiak
2018-08-08 14:44 ` [PATCH v8 22/22] s390: doc: detailed specifications " Tony Krowiak
2018-08-08 15:06 ` [PATCH v8 00/22] vfio-ap: guest dedicated crypto adapters Janosch Frank
2018-08-08 16:25 ` Cornelia Huck
2018-08-08 22:52   ` Tony Krowiak

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