On Thu, 21 Jan 2021 08:20:08 +0100 Halil Pasic pasic@linux.ibm.com wrote:
From: Tony Krowiak akrowiak@linux.ibm.com
The queues assigned to a matrix mediated device are currently reset when:
- The VFIO_DEVICE_RESET ioctl is invoked
- The mdev fd is closed by userspace (QEMU)
- The mdev is removed from sysfs.
Immediately after the reset of a queue, a call is made to disable interrupts for the queue. This is entirely unnecessary because the reset of a queue disables interrupts, so this will be removed.
Furthermore, vfio_ap_irq_disable() does an unconditional PQAP/AQIC which can result in a specification exception (when the corresponding facility is not available), so this is actually a bugfix.
Signed-off-by: Tony Krowiak akrowiak@linux.ibm.com [pasic@linux.ibm.com: minor rework before merging] Reviewed-by: Halil Pasic pasic@linux.ibm.com Signed-off-by: Halil Pasic pasic@linux.ibm.com Fixes: ec89b55e3bce ("s390: ap: implement PAPQ AQIC interception in kernel") Cc: stable@vger.kernel.org
Since it turned out disabling the interrupts via PQAP/AQIC is not only unnecesary but also buggy, we decided to put this patch, which used to be apart of the series https://lkml.org/lkml/2020/12/22/757 on the fast lane.
If the backports turn out to be a bother, which I hope won't be the case not, I am happy to help with those.
drivers/s390/crypto/vfio_ap_drv.c | 6 +- drivers/s390/crypto/vfio_ap_ops.c | 100 ++++++++++++++++---------- drivers/s390/crypto/vfio_ap_private.h | 12 ++-- 3 files changed, 69 insertions(+), 49 deletions(-)
(...)
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h index f46dde56b464..28e9d9989768 100644 --- a/drivers/s390/crypto/vfio_ap_private.h +++ b/drivers/s390/crypto/vfio_ap_private.h @@ -88,11 +88,6 @@ struct ap_matrix_mdev { struct mdev_device *mdev; }; -extern int vfio_ap_mdev_register(void); -extern void vfio_ap_mdev_unregister(void); -int vfio_ap_mdev_reset_queue(unsigned int apid, unsigned int apqi,
unsigned int retry);struct vfio_ap_queue { struct ap_matrix_mdev *matrix_mdev; unsigned long saved_pfn; @@ -100,5 +95,10 @@ struct vfio_ap_queue { #define VFIO_AP_ISC_INVALID 0xff unsigned char saved_isc; }; -struct ap_queue_status vfio_ap_irq_disable(struct vfio_ap_queue *q);
+int vfio_ap_mdev_register(void); +void vfio_ap_mdev_unregister(void);
Nit: was moving these two necessary?
+int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q,
unsigned int retry);#endif /* _VFIO_AP_PRIVATE_H_ */
base-commit: 9791581c049c10929e97098374dd1716a81fefcc
Anyway, if I didn't entangle myself in the various branches, this seems sane.
Reviewed-by: Cornelia Huck cohuck@redhat.com