[PATCH v6 13/24] vfio/iommufd: Split the compat_ioas attach out from vfio_iommufd_bind()

Yi Liu
2023-03-08T13:32:30Z

This makes the group code call .bind_iommufd and .attach_ioas in two steps
instead of in a single step. This prepares the bind_iommufd and attach_ioas
support in the coming cdev path.

Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
drivers/vfio/group.c | 26 ++++++++++-----
drivers/vfio/iommufd.c | 75 ++++++++++++++++++++++++++----------------
drivers/vfio/vfio.h | 8 +++++
3 files changed, 73 insertions(+), 36 deletions(-)

diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c
index 6280368eb0bd..555d68aefa71 100644
--- a/drivers/vfio/group.c
+++ b/drivers/vfio/group.c
@@ -177,7 +177,7 @@ static int vfio_device_group_open(struct vfio_device_file *df)
mutex_lock(&device->group->group_lock);
if (!vfio_group_has_iommu(device->group)) {
ret = -EINVAL;
- goto out_unlock;
+ goto err_unlock;
}

mutex_lock(&device->dev_set->lock);
@@ -194,9 +194,14 @@ static int vfio_device_group_open(struct vfio_device_file *df)
df->iommufd = device->group->iommufd;

ret = vfio_device_open(df);
- if (ret) {
- df->iommufd = NULL;
- goto out_put_kvm;
+ if (ret)
+ goto err_put_kvm;
+
+ if (device->group->iommufd) {
+ ret = vfio_iommufd_attach_compat_ioas(device,
+ device->group->iommufd);
+ if (ret)
+ goto err_close_device;
}

/*
@@ -205,13 +210,18 @@ static int vfio_device_group_open(struct vfio_device_file *df)
*/
smp_store_release(&df->access_granted, true);

-out_put_kvm:
+ mutex_unlock(&device->dev_set->lock);
+ mutex_unlock(&device->group->group_lock);
+ return 0;
+
+err_close_device:
+ vfio_device_close(df);
+err_put_kvm:
+ df->iommufd = NULL;
if (device->open_count == 0)
vfio_device_put_kvm(device);
-
mutex_unlock(&device->dev_set->lock);
-
-out_unlock:
+err_unlock:
mutex_unlock(&device->group->group_lock);
return ret;
}
diff --git a/drivers/vfio/iommufd.c b/drivers/vfio/iommufd.c
index 30c0da2e11f9..8c518f8bd39a 100644
--- a/drivers/vfio/iommufd.c
+++ b/drivers/vfio/iommufd.c
@@ -10,52 +10,71 @@
MODULE_IMPORT_NS(IOMMUFD);
MODULE_IMPORT_NS(IOMMUFD_VFIO);

-int vfio_iommufd_bind(struct vfio_device *vdev, struct iommufd_ctx *ictx)
+static int vfio_iommufd_device_probe_comapt_noiommu(struct vfio_device *vdev,
+ struct iommufd_ctx *ictx)
{
u32 ioas_id;
+
+ if (!capable(CAP_SYS_RAWIO))
+ return -EPERM;
+
+ /*
+ * Require no compat ioas to be assigned to proceed. The basic
+ * statement is that the user cannot have done something that
+ * implies they expected translation to exist
+ */
+ if (!iommufd_vfio_compat_ioas_get_id(ictx, &ioas_id))
+ return -EPERM;
+ return 0;
+}
+
+int vfio_iommufd_bind(struct vfio_device *vdev, struct iommufd_ctx *ictx)
+{
u32 device_id;
int ret;

lockdep_assert_held(&vdev->dev_set->lock);

if (vfio_device_is_noiommu(vdev)) {
- if (!capable(CAP_SYS_RAWIO))
- return -EPERM;
-
- /*
- * Require no compat ioas to be assigned to proceed. The basic
- * statement is that the user cannot have done something that
- * implies they expected translation to exist
- */
- if (!iommufd_vfio_compat_ioas_get_id(ictx, &ioas_id))
- return -EPERM;
- return 0;
+ ret = vfio_iommufd_device_probe_comapt_noiommu(vdev, ictx);
+ if (ret)
+ return ret;
}

if (WARN_ON(!vdev->ops->bind_iommufd))
return -ENODEV;

- ret = vdev->ops->bind_iommufd(vdev, ictx, &device_id);
- if (ret)
- return ret;
+ /* The legacy path has no way to return the device id */
+ return vdev->ops->bind_iommufd(vdev, ictx, &device_id);
+}

- ret = iommufd_vfio_compat_ioas_get_id(ictx, &ioas_id);
- if (ret)
- goto err_unbind;
- ret = vdev->ops->attach_ioas(vdev, &ioas_id);
- if (ret)
- goto err_unbind;
+int vfio_iommufd_attach_compat_ioas(struct vfio_device *vdev,
+ struct iommufd_ctx *ictx)
+{
+ u32 ioas_id;
+ int ret;
+
+ lockdep_assert_held(&vdev->dev_set->lock);

/*
- * The legacy path has no way to return the device id or the selected
- * pt_id
+ * If the driver doesn't provide this op then it means the device does
+ * not do DMA at all. So nothing to do.
*/
- return 0;
+ if (WARN_ON(!vdev->ops->bind_iommufd))
+ return -ENODEV;

-err_unbind:
- if (vdev->ops->unbind_iommufd)
- vdev->ops->unbind_iommufd(vdev);
- return ret;
+ if (vfio_device_is_noiommu(vdev)) {
+ if (WARN_ON(vfio_iommufd_device_probe_comapt_noiommu(vdev, ictx)))
+ return -EINVAL;
+ return 0;
+ }
+
+ ret = iommufd_vfio_compat_ioas_get_id(ictx, &ioas_id);
+ if (ret)
+ return ret;
+
+ /* The legacy path has no way to return the selected pt_id */
+ return vdev->ops->attach_ioas(vdev, &ioas_id);
}

void vfio_iommufd_unbind(struct vfio_device *vdev)
diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
index 464263288d16..3356321805e9 100644
--- a/drivers/vfio/vfio.h
+++ b/drivers/vfio/vfio.h
@@ -232,6 +232,8 @@ static inline void vfio_container_cleanup(void)
#if IS_ENABLED(CONFIG_IOMMUFD)
int vfio_iommufd_bind(struct vfio_device *device, struct iommufd_ctx *ictx);
void vfio_iommufd_unbind(struct vfio_device *device);
+int vfio_iommufd_attach_compat_ioas(struct vfio_device *vdev,
+ struct iommufd_ctx *ictx);
#else
static inline int vfio_iommufd_bind(struct vfio_device *device,
struct iommufd_ctx *ictx)
@@ -242,6 +244,12 @@ static inline int vfio_iommufd_bind(struct vfio_device *device,
static inline void vfio_iommufd_unbind(struct vfio_device *device)
{
}
+
+static inline int vfio_iommufd_attach_compat_ioas(struct vfio_device *vdev,
+ struct iommufd_ctx *ictx)
+{
+ return -EOPNOTSUPP;
+}
#endif

#if IS_ENABLED(CONFIG_VFIO_VIRQFD)
--
2.34.1