On 10/9/2023 4:51 PM, Yi Liu wrote:
From: Kevin Tian <kevin.tian@xxxxxxxxx>
This adds vfio_register_pasid_iommu_dev() for device driver to register
virtual devices which are isolated per PASID in physical IOMMU. The major
usage is for the SIOV devices which allows device driver to tag the DMAs
out of virtual devices within it with different PASIDs.
For a given vfio device, VFIO core creates both group user interface and
device user interface (device cdev) if configured. However, for the virtual
devices backed by PASID of the device, VFIO core shall only create device
user interface as there is no plan to support such devices in the legacy
vfio_iommu drivers which is a must if creating group user interface for
such virtual devices. This introduces a VFIO_PASID_IOMMU group type for
the device driver to register PASID virtual devices, and provides a wrapper
API for it. In particular no iommu group (neither fake group or real group)
exists per PASID, hence no group interface for this type.
Signed-off-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
---
+/*
+ * Register a virtual device with IOMMU pasid protection. The user of
+ * this device can trigger DMA as long as all of its outgoing DMAs are
+ * always tagged with a pasid.
+ */
+int vfio_register_pasid_iommu_dev(struct vfio_device *device)
+{
+ return __vfio_register_dev(device, VFIO_PASID_IOMMU);
+}
+
If CONFIG_VFIO_GROUP kconfig is selected, then there will be access to
vdev->group shown as below
->__vfio_register_dev()
->vfio_device_add()
->vfio_device_is_noiommu() { return
IS_ENABLED(CONFIG_VFIO_NOIOMMU) && vdev->group->type == VFIO_NO_IOMMU}
For SIOV virtual devices, vfio group is not created and vfio cdev is
used. Thus vdev->group is NULL and there is NULL pointer access here.
Thanks.
Yahui.
