Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH v2 7/8] s390: vfio-ap: handle bind and unbind of AP queue device | From | Tony Krowiak <> | Date | Tue, 23 Apr 2019 09:36:22 -0400 |
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On 4/23/19 9:08 AM, Pierre Morel wrote: > On 20/04/2019 23:49, Tony Krowiak wrote: >> There is an implied guarantee that when an AP queue device is bound to a >> device driver, that driver will have exclusive control over the device. >> When an AP queue device is unbound from the vfio_ap driver while the >> queue is in use by a guest and subsquently bound to a zcrypt driver, the >> guarantee that the zcrypt driver has exclusive control of the queue >> device will be violated. Likewise, when an AP queue device is bound to >> the vfio_ap device driver and its APQN is assigned to an mdev device in >> use by a guest, the expectation is that the guest will have access to >> the queue. >> >> The purpose of this patch is to ensure three things: >> >> 1. When an AP queue device in use by a guest is unbound, the guest shall >> no longer access the queue. Due to the limitations of the >> architecture, access to a single queue can not be denied to a guest, >> so access to the AP card to which the queue is connected will be >> denied to the guest. >> >> 2. When an AP queue device with an APQN assigned to an mdev device is >> bound to the vfio_ap driver while the mdev device is in use by a >> guest, >> the guest shall be granted access to the queue. >> >> 3. When a guest is started, each APQN assigned to the guest's mdev device >> must be owned by the vfio_ap driver. >> >> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com> >> --- >> drivers/s390/crypto/vfio_ap_drv.c | 16 ++++++- >> drivers/s390/crypto/vfio_ap_ops.c | 82 >> ++++++++++++++++++++++++++++++++++- >> drivers/s390/crypto/vfio_ap_private.h | 2 + >> 3 files changed, 97 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/s390/crypto/vfio_ap_drv.c >> b/drivers/s390/crypto/vfio_ap_drv.c >> index e9824c35c34f..0f5dafddf5b1 100644 >> --- a/drivers/s390/crypto/vfio_ap_drv.c >> +++ b/drivers/s390/crypto/vfio_ap_drv.c >> @@ -42,12 +42,26 @@ MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids); >> static int vfio_ap_queue_dev_probe(struct ap_device *apdev) >> { >> + struct ap_queue *apq = to_ap_queue(&apdev->device); >> + unsigned long apid = AP_QID_CARD(apq->qid); >> + unsigned long apqi = AP_QID_QUEUE(apq->qid); >> + >> + mutex_lock(&matrix_dev->lock); >> + vfio_ap_mdev_probe_queue(apid, apqi); >> + mutex_unlock(&matrix_dev->lock); >> + >> return 0; >> } >> static void vfio_ap_queue_dev_remove(struct ap_device *apdev) >> { >> - /* Nothing to do yet */ >> + struct ap_queue *apq = to_ap_queue(&apdev->device); >> + unsigned long apid = AP_QID_CARD(apq->qid); >> + unsigned long apqi = AP_QID_QUEUE(apq->qid); >> + >> + mutex_lock(&matrix_dev->lock); >> + vfio_ap_mdev_remove_queue(apid, apqi); >> + mutex_unlock(&matrix_dev->lock); >> } >> static void vfio_ap_matrix_dev_release(struct device *dev) >> diff --git a/drivers/s390/crypto/vfio_ap_ops.c >> b/drivers/s390/crypto/vfio_ap_ops.c >> index 31ce30ee784d..3f9506516545 100644 >> --- a/drivers/s390/crypto/vfio_ap_ops.c >> +++ b/drivers/s390/crypto/vfio_ap_ops.c >> @@ -763,8 +763,8 @@ static void vfio_ap_mdev_wait_for_qempty(unsigned >> long apid, unsigned long apqi) >> msleep(20); >> break; >> default: >> - pr_warn("%s: tapq err %02x: 0x%04x may not be empty\n", >> - __func__, status.response_code, q->apqn); >> + pr_warn("%s: tapq err %02x: %02lx%04lx may not be empty\n", >> + __func__, status.response_code, apid, apqi); >> return; >> } >> } while (--retry); >> @@ -823,6 +823,14 @@ static int vfio_ap_mdev_reset_queues(struct >> mdev_device *mdev) >> static int vfio_ap_mdev_create_shadow_crycb(struct ap_matrix_mdev >> *matrix_mdev) >> { >> + /* >> + * If an AP resource is not owned by the vfio_ap driver - e.g., >> it was >> + * unbound from the driver while still assigned to the mdev device >> + */ >> + if (ap_apqn_in_matrix_owned_by_def_drv(matrix_mdev->matrix.apm, >> + matrix_mdev->matrix.aqm)) >> + return -EADDRNOTAVAIL; >> + >> matrix_mdev->shadow_crycb = >> kzalloc(sizeof(*matrix_mdev->shadow_crycb), >> GFP_KERNEL); >> if (!matrix_mdev->shadow_crycb) >> @@ -847,6 +855,18 @@ static int vfio_ap_mdev_open(struct mdev_device >> *mdev) >> if (!try_module_get(THIS_MODULE)) >> return -ENODEV; >> + ret = ap_apqn_in_matrix_owned_by_def_drv(matrix_mdev->matrix.apm, >> + matrix_mdev->matrix.aqm); >> + >> + /* >> + * If any APQN is owned by a default driver, it can not be used >> by the >> + * guest. This can happen if a queue is unbound from the vfio_ap >> + * driver but not unassigned from the mdev device. >> + */ >> + ret = (ret == 1) ? -EADDRNOTAVAIL : ret; >> + if (ret) >> + return ret; >> + >> matrix_mdev->group_notifier.notifier_call = >> vfio_ap_mdev_group_notifier; >> events = VFIO_GROUP_NOTIFY_SET_KVM; >> @@ -938,3 +958,61 @@ void vfio_ap_mdev_unregister(void) >> { >> mdev_unregister_device(&matrix_dev->device); >> } >> + >> +static struct ap_matrix_mdev *vfio_ap_mdev_find_matrix_mdev(unsigned >> long apid, >> + unsigned long apqi) >> +{ >> + struct ap_matrix_mdev *matrix_mdev; >> + >> + list_for_each_entry(matrix_mdev, &matrix_dev->mdev_list, node) { >> + if (test_bit_inv(apid, matrix_mdev->matrix.apm) && >> + test_bit_inv(apqi, matrix_mdev->matrix.aqm)) >> + return matrix_mdev; >> + } >> + >> + return NULL; >> +} >> + >> +void vfio_ap_mdev_remove_queue(unsigned long apid, unsigned long apqi) >> +{ >> + struct ap_matrix_mdev *matrix_mdev; >> + >> + matrix_mdev = vfio_ap_mdev_find_matrix_mdev(apid, apqi); >> + >> + /* >> + * If the queue is assigned to the mdev device and the mdev device >> + * is in use by a guest >> + */ >> + if (matrix_mdev && matrix_mdev->kvm) { >> + /* >> + * Unplug the adapter from the guest but don't unassign it >> + * from the mdev device >> + */ >> + clear_bit_inv(apid, matrix_mdev->shadow_crycb->apm); >> + vfio_ap_mdev_update_crycb(matrix_mdev); >> + } >> + >> + vfio_ap_mdev_reset_queue(apid, apqi); >> +} >> + >> +void vfio_ap_mdev_probe_queue(unsigned long apid, unsigned long apqi) >> +{ >> + struct ap_matrix_mdev *matrix_mdev; >> + >> + matrix_mdev = vfio_ap_mdev_find_matrix_mdev(apid, apqi); >> + >> + /* >> + * If the queue is assigned to the mdev device and the mdev device >> + * is in use by a guest >> + */ >> + if (matrix_mdev && matrix_mdev->kvm) { >> + /* Plug the adapter into the guest */ >> + set_bit_inv(apid, matrix_mdev->shadow_crycb->apm); >> + >> + /* Make sure the queue is also plugged in to the guest */ >> + if (!test_bit_inv(apqi, matrix_mdev->shadow_crycb->aqm)) >> + set_bit_inv(apqi, matrix_mdev->shadow_crycb->aqm); > > Why are you testing the domain before setting it and not the adapter? > > Eventually you do not need to test at all or if, then both.
My thinking was that when a queue is removed, we clear only the APID from the APM, but do not clear the APQI from the AQM. I think you are correct in saying we do not need to test either mask since we are plugging the queue in regardless.
> > NIT > > >> + >> + vfio_ap_mdev_update_crycb(matrix_mdev); >> + } >> +} >> diff --git a/drivers/s390/crypto/vfio_ap_private.h >> b/drivers/s390/crypto/vfio_ap_private.h >> index e8457aa61976..00eaae3b853f 100644 >> --- a/drivers/s390/crypto/vfio_ap_private.h >> +++ b/drivers/s390/crypto/vfio_ap_private.h >> @@ -87,5 +87,7 @@ struct ap_matrix_mdev { >> extern int vfio_ap_mdev_register(void); >> extern void vfio_ap_mdev_unregister(void); >> +void vfio_ap_mdev_remove_queue(unsigned long apid, unsigned long apqi); >> +void vfio_ap_mdev_probe_queue(unsigned long apid, unsigned long apqi); >> #endif /* _VFIO_AP_PRIVATE_H_ */ >> > >
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