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vfio: Remove use of vfio_group_viable()

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As DMA ownership is claimed for the iommu group when a VFIO group is
added to a VFIO container, the VFIO group viability is guaranteed as long
as group->container_users > 0. Remove those unnecessary group viability
checks which are only hit when group->container_users is not zero.

The only remaining reference is in GROUP_GET_STATUS, which could be called
at any time when group fd is valid. Here we just replace the
vfio_group_viable() by directly calling IOMMU core to get viability status.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/r/20220418005000.897664-9-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Lu Baolu 2022-04-18 08:49:57 +08:00 committed by Joerg Roedel
parent 70693f4708
commit 31076af0cb
1 changed files with 6 additions and 12 deletions
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18
drivers/vfio/vfio.c
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@ -1313,12 +1313,6 @@ unlock_out:
return ret;
}
static bool vfio_group_viable(struct vfio_group *group)
{
return (iommu_group_for_each_dev(group->iommu_group,
group, vfio_dev_viable) == 0);
}
static int vfio_group_add_container_user(struct vfio_group *group)
{
if (!atomic_inc_not_zero(&group->container_users))
@ -1328,7 +1322,7 @@ static int vfio_group_add_container_user(struct vfio_group *group)
atomic_dec(&group->container_users);
return -EPERM;
}
if (!group->container->iommu_driver || !vfio_group_viable(group)) {
if (!group->container->iommu_driver) {
atomic_dec(&group->container_users);
return -EINVAL;
}
@ -1346,7 +1340,7 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
int ret = 0;
if (0 == atomic_read(&group->container_users) ||
!group->container->iommu_driver || !vfio_group_viable(group))
!group->container->iommu_driver)
return -EINVAL;
if (group->type == VFIO_NO_IOMMU && !capable(CAP_SYS_RAWIO))
@ -1438,11 +1432,11 @@ static long vfio_group_fops_unl_ioctl(struct file *filep,
status.flags = 0;
if (vfio_group_viable(group))
status.flags |= VFIO_GROUP_FLAGS_VIABLE;
if (group->container)
status.flags |= VFIO_GROUP_FLAGS_CONTAINER_SET;
status.flags |= VFIO_GROUP_FLAGS_CONTAINER_SET |
VFIO_GROUP_FLAGS_VIABLE;
else if (!iommu_group_dma_owner_claimed(group->iommu_group))
status.flags |= VFIO_GROUP_FLAGS_VIABLE;
if (copy_to_user((void __user *)arg, &status, minsz))
return -EFAULT;