As DMA USER 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@xxxxxxxxxxxxxxx>
---
drivers/vfio/vfio.c | 18 ++++++------------
1 file changed, 6 insertions(+), 12 deletions(-)
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 00f89acfec39..63e24f746b82 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1316,12 +1316,6 @@ 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))
@@ -1331,7 +1325,7 @@ 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;
}
@@ -1349,7 +1343,7 @@ 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))
@@ -1441,11 +1435,11 @@ 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_unclaimed(group->iommu_group))
+ status.flags |= VFIO_GROUP_FLAGS_VIABLE;
if (copy_to_user((void __user *)arg, &status, minsz))
return -EFAULT;
--
2.25.1
