On 2023/11/16 13:35, Cao, Yahui wrote:
On 10/9/2023 4:51 PM, Yi Liu wrote:
From: Kevin Tian kevin.tian@intel.com
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@intel.com Signed-off-by: Yi Liu yi.l.liu@intel.com
+/*
- 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.
yes. needs to be like below:
return IS_ENABLED(CONFIG_VFIO_NOIOMMU) && vdev->group && vdev->group->type == VFIO_NO_IOMMU;