lkml.org 
[lkml]   [2021]   [Jun]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v5 1/2] s390/vfio-ap: clean up mdev resources when remove callback invoked
From
Date


On 16.06.21 16:16, Tony Krowiak wrote:
> The mdev remove callback for the vfio_ap device driver bails out with
> -EBUSY if the mdev is in use by a KVM guest (i.e., the KVM pointer in the
> struct ap_matrix_mdev is not NULL). The intended purpose was
> to prevent the mdev from being removed while in use. There are two
> problems with this scenario:
>
> 1. Returning a non-zero return code from the remove callback does not
> prevent the removal of the mdev.
>
> 2. The KVM pointer in the struct ap_matrix_mdev will always be NULL because
> the remove callback will not get invoked until the mdev fd is closed.
> When the mdev fd is closed, the mdev release callback is invoked and
> clears the KVM pointer from the struct ap_matrix_mdev.
>
> Let's go ahead and remove the check for KVM in the remove callback and
> allow the cleanup of mdev resources to proceed.
>
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

queued. Do we need cc stable?

> ---
> drivers/s390/crypto/vfio_ap_ops.c | 10 ----------
> 1 file changed, 10 deletions(-)
>
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index b2c7e10dfdcd..122c85c22469 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -366,16 +366,6 @@ static int vfio_ap_mdev_remove(struct mdev_device *mdev)
> struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
>
> mutex_lock(&matrix_dev->lock);
> -
> - /*
> - * If the KVM pointer is in flux or the guest is running, disallow
> - * un-assignment of control domain.
> - */
> - if (matrix_mdev->kvm_busy || matrix_mdev->kvm) {
> - mutex_unlock(&matrix_dev->lock);
> - return -EBUSY;
> - }
> -
> vfio_ap_mdev_reset_queues(mdev);
> list_del(&matrix_mdev->node);
> kfree(matrix_mdev);
>

\
 
 \ /
  Last update: 2021-06-17 11:02    [W:0.118 / U:0.736 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site