diff mbox series

[v7,08/11] vfio: Remove use of vfio_group_viable()

Message ID 20220228005056.599595-9-baolu.lu@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series Fix BUG_ON in vfio_iommu_group_notifier() | expand

Commit Message

Baolu Lu Feb. 28, 2022, 12:50 a.m. UTC 
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>
---
 drivers/vfio/vfio.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

Comments

Alex Williamson Feb. 28, 2022, 10:06 p.m. UTC | #1 
On Mon, 28 Feb 2022 08:50:53 +0800
Lu Baolu <baolu.lu@linux.intel.com> wrote:

> 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>
> ---
>  drivers/vfio/vfio.c | 18 ++++++------------
>  1 file changed, 6 insertions(+), 12 deletions(-)

Acked-by: Alex Williamson <alex.williamson@redhat.com>
diff mbox series

Patch

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index df9d4b60e5ae..73034446e03f 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -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;