On Thu, 21 Jan 2021 08:20:08 +0100
Halil Pasic <pasic@xxxxxxxxxxxxx> wrote:
> From: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxxx>
> [pasic@xxxxxxxxxxxxx: minor rework before merging]
> Reviewed-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
> Signed-off-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
> Fixes: ec89b55e3bce ("s390: ap: implement PAPQ AQIC interception in kernel")
> Cc: <stable@xxxxxxxxxxxxxxx>
>
> ---
>
> 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@xxxxxxxxxx>
