From: Cornelia Huck <cohuck@redhat.com>
To: Halil Pasic <pasic@linux.ibm.com>
Cc: 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, Tony Krowiak <akrowiak@linux.ibm.com>
Subject: Re: [PATCH v10 13/26] s390: vfio-ap: zeroize the AP queues
Date: Mon, 24 Sep 2018 14:32:47 +0200 [thread overview]
Message-ID: <20180924143247.4f4d656e.cohuck@redhat.com> (raw)
In-Reply-To: <b2eae775-0917-8c71-4ecf-6ef921ac9b0b@linux.ibm.com>
On Mon, 24 Sep 2018 14:16:42 +0200
Halil Pasic <pasic@linux.ibm.com> wrote:
> On 09/24/2018 01:36 PM, Cornelia Huck wrote:
> > On Wed, 12 Sep 2018 15:43:03 -0400
> > Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote:
> >> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> >> index f8b276a..48b1b78 100644
> >> --- a/drivers/s390/crypto/vfio_ap_ops.c
> >> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> >> @@ -829,6 +829,49 @@ static int vfio_ap_mdev_group_notifier(struct notifier_block *nb,
> >> return NOTIFY_OK;
> >> }
> >>
> >> +static int vfio_ap_mdev_reset_queue(unsigned int apid, unsigned int apqi,
> >> + unsigned int retry)
> >> +{
> >> + struct ap_queue_status status;
> >> +
> >> + do {
> >> + status = ap_zapq(AP_MKQID(apid, apqi));
> >> + switch (status.response_code) {
> >> + case AP_RESPONSE_NORMAL:
> >> + return 0;
> >> + case AP_RESPONSE_RESET_IN_PROGRESS:
> >> + case AP_RESPONSE_BUSY:
> >> + msleep(20);
> >> + break;
> >> + default:
> >> + /* things are really broken, give up */
> >> + return -EIO;
> >> + }
> >> + } while (retry--);
> >> +
> >> + return -EBUSY;
> >
> > So, this function may either return 0, -EIO (things are really broken),
> > or -EBUSY (still busy after multiple tries)...
> >
> >> +}
> >> +
> >> +static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev)
> >> +{
> >> + int ret;
> >> + int rc = 0;
> >> + unsigned long apid, apqi;
> >> + struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> >> +
> >> + for_each_set_bit_inv(apid, matrix_mdev->matrix.apm,
> >> + matrix_mdev->matrix.apm_max + 1) {
> >> + for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm,
> >> + matrix_mdev->matrix.aqm_max + 1) {
> >> + ret = vfio_ap_mdev_reset_queue(apid, apqi, 1);
> >> + if (ret)
> >> + rc = ret;
> >
> > ...and here, we return the last error of any of the resets. Two
> > questions:
> >
> > - Does it make sense to continue if we get -EIO? IOW, does "really
> > broken" only refer to a certain tuple and other tuples still can/need
> > to be reset?
>
> I think it does make sense to continue, because IMHO "things are really
> broken" is an overstatement (I mean the APQN invalid case). One could
> argue would skipping the current card (adapter) be justified or not.
A short comment ("even after -EIO, other devices still need to be
reset") may be helpful here (remember that I don't have any way to
verify this with the architecture).
>
> IMHO the current code is good enough for the first shot, and we can think
> about fine-tuning it later.
Sure.
>
> > - Is the return code useful in any way, as we don't know which tuple it
> > refers to?
> >
>
> Well, good question. It conveys that the operation can 'fail'. AFAIR -EBUSY
> is mostly fine given what the architecture say if we are satisfied with just
> reset. And the cases behind -EIO might actually be OK too in the same sense.
> My guess is, that based on the return value client code can tell if we have
> zeroize for all queues or basically just reset (like rapq). We could log that
> to some debug facility or whatever -- I guess, but at the moment we don't care.
Logging would probably be more useful than the return code, but that
can be added later.
>
> In the end I think the code is good enough as is, and if we want we can
> improve on it later.
I don't object to that; but this is all a bit confusing to readers
without access to the architecture, so I think a comment or two would
really improve things.
>
> Regards,
> Halil
>
>
> >> + }
> >> + }
> >> +
> >> + return rc;
> >> +}
> >> +
> >> static int vfio_ap_mdev_open(struct mdev_device *mdev)
> >> {
> >> struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> >> @@ -859,6 +902,7 @@ static void vfio_ap_mdev_release(struct mdev_device *mdev)
> >> if (matrix_mdev->kvm)
> >> kvm_arch_crypto_clear_masks(matrix_mdev->kvm);
> >>
> >> + vfio_ap_mdev_reset_queues(mdev);
> >> vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
> >> &matrix_mdev->group_notifier);
> >> matrix_mdev->kvm = NULL;
> >
>
next prev parent reply other threads:[~2018-09-24 12:33 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-12 19:42 [PATCH v10 00/26] guest dedicated crypto adapters Tony Krowiak
2018-09-12 19:42 ` [PATCH v10 01/26] KVM: s390: vsie: simulate VCPU SIE entry/exit Tony Krowiak
2018-09-24 10:32 ` Christian Borntraeger
2018-09-24 16:53 ` Tony Krowiak
2018-09-12 19:42 ` [PATCH v10 02/26] KVM: s390: introduce and use KVM_REQ_VSIE_RESTART Tony Krowiak
2018-09-24 10:49 ` Christian Borntraeger
2018-09-24 16:48 ` Tony Krowiak
2018-09-12 19:42 ` [PATCH v10 03/26] KVM: s390: refactor crypto initialization Tony Krowiak
2018-09-21 23:18 ` Tony Krowiak
2018-09-24 8:35 ` David Hildenbrand
2018-09-24 10:34 ` Cornelia Huck
2018-09-12 19:42 ` [PATCH v10 04/26] s390: vfio-ap: base implementation of VFIO AP device driver Tony Krowiak
2018-09-20 15:31 ` Cornelia Huck
2018-09-20 15:53 ` Tony Krowiak
2018-09-12 19:42 ` [PATCH v10 05/26] s390: vfio-ap: register matrix device with VFIO mdev framework Tony Krowiak
2018-09-20 15:50 ` Cornelia Huck
2018-09-20 20:35 ` Tony Krowiak
2018-09-12 19:42 ` [PATCH v10 06/26] s390: vfio-ap: sysfs interfaces to configure adapters Tony Krowiak
2018-09-21 9:40 ` Cornelia Huck
2018-09-21 9:52 ` Harald Freudenberger
2018-09-21 14:07 ` Tony Krowiak
2018-09-12 19:42 ` [PATCH v10 07/26] s390: vfio-ap: sysfs interfaces to configure domains Tony Krowiak
2018-09-24 10:45 ` Cornelia Huck
2018-09-12 19:42 ` [PATCH v10 08/26] s390: vfio-ap: sysfs interfaces to configure control domains Tony Krowiak
2018-09-24 10:57 ` Cornelia Huck
2018-09-12 19:42 ` [PATCH v10 09/26] s390: vfio-ap: sysfs interface to view matrix mdev matrix Tony Krowiak
2018-09-24 10:59 ` Cornelia Huck
2018-09-12 19:43 ` [PATCH v10 10/26] KVM: s390: interfaces to clear CRYCB masks Tony Krowiak
2018-09-24 11:01 ` Cornelia Huck
2018-09-24 11:50 ` Halil Pasic
2018-09-24 12:01 ` Cornelia Huck
2018-09-24 15:33 ` Tony Krowiak
2018-09-24 14:49 ` Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 11/26] s390: vfio-ap: implement mediated device open callback Tony Krowiak
2018-09-18 17:00 ` Halil Pasic
2018-09-18 21:57 ` Tony Krowiak
2018-09-21 23:28 ` Tony Krowiak
2018-09-24 8:40 ` David Hildenbrand
2018-09-24 16:07 ` Tony Krowiak
2018-09-24 18:40 ` David Hildenbrand
2018-09-24 18:43 ` Tony Krowiak
2018-09-24 19:46 ` Tony Krowiak
2018-09-24 19:55 ` David Hildenbrand
2018-09-25 19:54 ` Tony Krowiak
2018-09-25 19:55 ` David Hildenbrand
2018-09-12 19:43 ` [PATCH v10 12/26] s390: vfio-ap: implement VFIO_DEVICE_GET_INFO ioctl Tony Krowiak
2018-09-24 11:43 ` Cornelia Huck
2018-09-24 16:29 ` Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 13/26] s390: vfio-ap: zeroize the AP queues Tony Krowiak
2018-09-24 11:36 ` Cornelia Huck
2018-09-24 12:16 ` Halil Pasic
2018-09-24 12:32 ` Cornelia Huck [this message]
2018-09-24 13:22 ` Harald Freudenberger
2018-09-24 16:42 ` Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 14/26] s390: vfio-ap: implement VFIO_DEVICE_RESET ioctl Tony Krowiak
2018-09-24 11:43 ` Cornelia Huck
2018-09-12 19:43 ` [PATCH v10 15/26] KVM: s390: Clear Crypto Control Block when using vSIE Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 16/26] KVM: s390: vsie: Do the CRYCB validation first Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 17/26] KVM: s390: vsie: Make use of CRYCB FORMAT2 clear Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 18/26] KVM: s390: vsie: Allow CRYCB FORMAT-2 Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 19/26] KVM: s390: vsie: allow CRYCB FORMAT-1 Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 20/26] KVM: s390: vsie: allow CRYCB FORMAT-0 Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 21/26] KVM: s390: vsie: allow guest FORMAT-0 CRYCB on host FORMAT-1 Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 22/26] KVM: s390: vsie: allow guest FORMAT-1 CRYCB on host FORMAT-2 Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 23/26] KVM: s390: vsie: allow guest FORMAT-0 " Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 24/26] KVM: s390: device attrs to enable/disable AP interpretation Tony Krowiak
2018-09-17 8:51 ` David Hildenbrand
2018-09-21 23:40 ` Tony Krowiak
2018-09-24 11:23 ` David Hildenbrand
2018-09-24 16:25 ` Tony Krowiak
2018-09-24 18:42 ` Tony Krowiak
2018-09-24 18:51 ` David Hildenbrand
2018-09-25 13:24 ` Tony Krowiak
2018-09-25 7:32 ` David Hildenbrand
2018-09-25 13:26 ` Tony Krowiak
2018-09-24 18:46 ` David Hildenbrand
2018-09-25 13:31 ` Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 25/26] KVM: s390: CPU model support for AP virtualization Tony Krowiak
2018-09-21 23:31 ` Tony Krowiak
2018-09-24 8:33 ` David Hildenbrand
2018-09-12 19:43 ` [PATCH v10 26/26] s390: doc: detailed specifications " Tony Krowiak
2018-09-24 10:10 ` [PATCH v10 00/26] guest dedicated crypto adapters Christian Borntraeger
2018-09-24 11:53 ` Cornelia Huck
2018-09-24 16:46 ` Tony Krowiak
2018-09-24 16:50 ` Tony Krowiak
2018-09-24 11:49 ` Cornelia Huck
2018-09-24 16:45 ` Tony Krowiak
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