Messages in this thread | | | Subject | Re: [PATCH v8 17/22] s390: vfio-ap: zeroize the AP queues. | From | Tony Krowiak <> | Date | Fri, 10 Aug 2018 12:24:47 -0400 |
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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?
> >> Maybe Alex can confirm this point, if not we can remove the test.
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