vfio-iommufd: Support pasid [at|de]tach for physical VFIO devices

This adds pasid_at|de]tach_ioas ops for attaching hwpt to pasid of a
device and the helpers for it. For now, only vfio-pci supports pasid
attach/detach.

Link: https://patch.msgid.link/r/20250321180143.8468-3-yi.l.liu@intel.com
Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

1 files changed, 50 insertions, 0 deletions

diff --git a/drivers/vfio/iommufd.c b/drivers/vfio/iommufd.c
index 37e1efa2c7bf..c8c3a2d53f86 100644
--- a/drivers/vfio/iommufd.c
+++ b/drivers/vfio/iommufd.c
@@ -119,14 +119,22 @@ int vfio_iommufd_physical_bind(struct vfio_device *vdev,
 	if (IS_ERR(idev))
 		return PTR_ERR(idev);
 	vdev->iommufd_device = idev;
+	ida_init(&vdev->pasids);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(vfio_iommufd_physical_bind);
 
 void vfio_iommufd_physical_unbind(struct vfio_device *vdev)
 {
+	int pasid;
+
 	lockdep_assert_held(&vdev->dev_set->lock);
 
+	while ((pasid = ida_find_first(&vdev->pasids)) >= 0) {
+		iommufd_device_detach(vdev->iommufd_device, pasid);
+		ida_free(&vdev->pasids, pasid);
+	}
+
 	if (vdev->iommufd_attached) {
 		iommufd_device_detach(vdev->iommufd_device, IOMMU_NO_PASID);
 		vdev->iommufd_attached = false;
@@ -170,6 +178,48 @@ void vfio_iommufd_physical_detach_ioas(struct vfio_device *vdev)
 }
 EXPORT_SYMBOL_GPL(vfio_iommufd_physical_detach_ioas);
 
+int vfio_iommufd_physical_pasid_attach_ioas(struct vfio_device *vdev,
+					    u32 pasid, u32 *pt_id)
+{
+	int rc;
+
+	lockdep_assert_held(&vdev->dev_set->lock);
+
+	if (WARN_ON(!vdev->iommufd_device))
+		return -EINVAL;
+
+	if (ida_exists(&vdev->pasids, pasid))
+		return iommufd_device_replace(vdev->iommufd_device,
+					      pasid, pt_id);
+
+	rc = ida_alloc_range(&vdev->pasids, pasid, pasid, GFP_KERNEL);
+	if (rc < 0)
+		return rc;
+
+	rc = iommufd_device_attach(vdev->iommufd_device, pasid, pt_id);
+	if (rc)
+		ida_free(&vdev->pasids, pasid);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(vfio_iommufd_physical_pasid_attach_ioas);
+
+void vfio_iommufd_physical_pasid_detach_ioas(struct vfio_device *vdev,
+					     u32 pasid)
+{
+	lockdep_assert_held(&vdev->dev_set->lock);
+
+	if (WARN_ON(!vdev->iommufd_device))
+		return;
+
+	if (!ida_exists(&vdev->pasids, pasid))
+		return;
+
+	iommufd_device_detach(vdev->iommufd_device, pasid);
+	ida_free(&vdev->pasids, pasid);
+}
+EXPORT_SYMBOL_GPL(vfio_iommufd_physical_pasid_detach_ioas);
+
 /*
  * The emulated standard ops mean that vfio_device is going to use the
  * "mdev path" and will call vfio_pin_pages()/vfio_dma_rw(). Drivers using this