Messages in this thread | | | Subject | Re: [PATCH v2 6/7] s390: vfio-ap: handle bind and unbind of AP queue device | From | Tony Krowiak <> | Date | Mon, 6 May 2019 16:43:44 -0400 |
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On 5/6/19 6:55 AM, Pierre Morel wrote: > On 03/05/2019 23:14, Tony Krowiak wrote: >> There is nothing preventing a root user from inadvertently unbinding an >> AP queue device that is in use by a guest from the vfio_ap device driver >> and binding it to a zcrypt driver. This can result in a queue being >> accessible from both the host and a guest. >> >> This patch introduces safeguards that prevent sharing of an AP queue >> between the host when a queue device is unbound from the vfio_ap device >> driver. In addition, this patch restores guest access to AP queue devices >> bound to the vfio_ap driver if the queue's APQN is assigned to an mdev >> device in use by a guest. >> >> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com> >> --- >> drivers/s390/crypto/vfio_ap_drv.c | 12 +++- >> drivers/s390/crypto/vfio_ap_ops.c | 100 >> +++++++++++++++++++++++++++++++++- >> drivers/s390/crypto/vfio_ap_private.h | 2 + >> 3 files changed, 111 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/s390/crypto/vfio_ap_drv.c >> b/drivers/s390/crypto/vfio_ap_drv.c >> index e9824c35c34f..c215978daf39 100644 >> --- a/drivers/s390/crypto/vfio_ap_drv.c >> +++ b/drivers/s390/crypto/vfio_ap_drv.c >> @@ -42,12 +42,22 @@ MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids); >> static int vfio_ap_queue_dev_probe(struct ap_device *apdev) >> { >> + struct ap_queue *queue = to_ap_queue(&apdev->device); >> + >> + mutex_lock(&matrix_dev->lock); >> + vfio_ap_mdev_probe_queue(queue); >> + 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 *queue = to_ap_queue(&apdev->device); >> + >> + mutex_lock(&matrix_dev->lock); >> + vfio_ap_mdev_remove_queue(queue); >> + 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 ede45184eb67..40324951bd37 100644 >> --- a/drivers/s390/crypto/vfio_ap_ops.c >> +++ b/drivers/s390/crypto/vfio_ap_ops.c >> @@ -226,8 +226,6 @@ static struct device >> *vfio_ap_get_queue_dev(unsigned long apid, >> &apqn, match_apqn); >> } >> - >> - >> static int vfio_ap_mdev_validate_masks(unsigned long *apm, unsigned >> long *aqm) >> { >> int ret; >> @@ -259,6 +257,27 @@ static bool vfio_ap_queues_on_drv(unsigned long >> *apm, unsigned long *aqm) >> return true; >> } >> +static bool vfio_ap_card_on_drv(struct ap_queue *queue, unsigned long >> *aqm) >> +{ >> + unsigned long apid, apqi; >> + struct device *dev; >> + >> + apid = AP_QID_CARD(queue->qid); >> + >> + for_each_set_bit_inv(apqi, aqm, AP_DOMAINS) { >> + if (queue->qid == AP_MKQID(apid, apqi)) >> + continue; >> + >> + dev = vfio_ap_get_queue_dev(apid, apqi); >> + if (!dev) >> + return false; >> + >> + put_device(dev); >> + } >> + >> + return true; >> +} >> + >> /** >> * assign_adapter_store >> * >> @@ -1017,3 +1036,80 @@ 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_probe_queue(struct ap_queue *queue) >> +{ >> + struct ap_matrix_mdev *matrix_mdev; >> + unsigned long *shadow_apm, *shadow_aqm; >> + unsigned long apid = AP_QID_CARD(queue->qid); >> + unsigned long apqi = AP_QID_QUEUE(queue->qid); >> + >> + /* >> + * Find the mdev device to which the APQN of the queue device being >> + * probed is assigned >> + */ >> + matrix_mdev = vfio_ap_mdev_find_matrix_mdev(apid, apqi); >> + >> + /* Check whether we found an mdev device and it is in use by a >> guest */ >> + if (matrix_mdev && matrix_mdev->kvm) { >> + shadow_apm = matrix_mdev->shadow_crycb->apm; >> + shadow_aqm = matrix_mdev->shadow_crycb->aqm; >> + /* >> + * If the guest already has access to the adapter card >> + * referenced by APID or does not have access to the queues >> + * referenced by APQI, there is nothing to do here. >> + */ >> + if (test_bit_inv(apid, shadow_apm) || >> + !test_bit_inv(apqi, shadow_aqm)) >> + return; >> + >> + /* >> + * If each APQN with the APID of the queue being probed and an >> + * APQI in the shadow CRYCB references a queue device that is >> + * bound to the vfio_ap driver, then plug the adapter into the >> + * guest. >> + */ >> + if (vfio_ap_card_on_drv(queue, shadow_aqm)) { >> + set_bit_inv(apid, shadow_apm); >> + vfio_ap_mdev_update_crycb(matrix_mdev); >> + } >> + } >> +} >> + >> +void vfio_ap_mdev_remove_queue(struct ap_queue *queue) >> +{ >> + struct ap_matrix_mdev *matrix_mdev; >> + unsigned long apid = AP_QID_CARD(queue->qid); >> + unsigned long apqi = AP_QID_QUEUE(queue->qid); >> + >> + 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, unplug the adapter referred to by the APID >> + * of the APQN of the queue being removed. >> + */ >> + if (matrix_mdev && matrix_mdev->kvm) { >> + if (!test_bit_inv(apid, matrix_mdev->shadow_crycb->apm)) >> + return; >> + >> + clear_bit_inv(apid, matrix_mdev->shadow_crycb->apm); >> + vfio_ap_mdev_update_crycb(matrix_mdev); >> + } >> + >> + vfio_ap_mdev_reset_queue(apid, apqi); >> +} >> diff --git a/drivers/s390/crypto/vfio_ap_private.h >> b/drivers/s390/crypto/vfio_ap_private.h >> index e8457aa61976..6b1f7df5b979 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(struct ap_queue *queue); >> +void vfio_ap_mdev_probe_queue(struct ap_queue *queue); >> #endif /* _VFIO_AP_PRIVATE_H_ */ >> > > > AFAIU the apmask/aqmask of the AP_BUS are replacing bind/unbind for the > admin. Don't they?
Yes, these interfaces are used to bind/unbind.
> Then why not suppress bind/unbind for ap_queues?
I did suppress them in a previous version, but I believe Harald objected. I don't recall the reason. If any other maintainers agree with this, I can reinstate that change. I personally would prefer that. I think leaving the bind/unbind interfaces confuses the issue.
> > Otherwise, it seems to me to handle correctly the disappearance of a > card, which is the only thing that can happen from out of the firmware > queue change requires configuration change and re-IPL.
You are correct.
> > Even still need testing, LGTM
I would welcome and appreciate additional testing, thanks in advance.
> >
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