Commit 31076af0 authored by Lu Baolu's avatar Lu Baolu Committed by Joerg Roedel
Browse files

vfio: Remove use of vfio_group_viable() 



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: default avatarLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Acked-by: default avatarAlex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/r/20220418005000.897664-9-baolu.lu@linux.intel.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 70693f47

drivers/vfio/vfio.c

+6 −12
Original line number Diff line number Diff line
@@ -1313,12 +1313,6 @@ static int vfio_group_set_container(struct vfio_group *group, int container_fd) 
	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;