[PATCH RFC v1 2/3] iommufd: Add IOMMUFD_CMD_DEVICE_SET_RID and IOMMUFD_CMD_DEVICE_UNSET_RID

[Nicolin Chen]

Add a new pair of ioctls to allow user space to set user space Request ID
for a passthrough PCI device. This is to create a link between a physical
RID and a virtual RID in the IOMMU driver that cares.

Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
---
 drivers/iommu/iommufd/device.c          | 39 +++++++++++++++++++++++++
 drivers/iommu/iommufd/iommufd_private.h |  2 ++
 drivers/iommu/iommufd/main.c            |  4 +++
 include/uapi/linux/iommufd.h            | 31 ++++++++++++++++++++
 4 files changed, 76 insertions(+)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 207b0e3fd9c8..db756e5cd77b 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -735,6 +735,45 @@ void iommufd_device_detach(struct iommufd_device *idev)
 }
 EXPORT_SYMBOL_NS_GPL(iommufd_device_detach, IOMMUFD);
 
+int iommufd_device_set_rid(struct iommufd_ucmd *ucmd)
+{
+	struct iommufd_device_set_rid *cmd = ucmd->cmd;
+	struct iommufd_device *idev;
+	const struct iommu_ops *ops;
+	int rc = 0;
+
+	if (!cmd->rid)
+		return -EINVAL;
+
+	idev = iommufd_get_device(ucmd, cmd->dev_id);
+	if (IS_ERR(idev))
+		return PTR_ERR(idev);
+
+	ops = dev_iommu_ops(idev->dev);
+	if (ops && ops->set_rid_user)
+		rc = ops->set_rid_user(idev->dev, cmd->rid, cmd->rid_base);
+	iommufd_put_object(&idev->obj);
+	return rc;
+}
+
+int iommufd_device_unset_rid(struct iommufd_ucmd *ucmd)
+{
+	struct iommufd_device_unset_rid *cmd = ucmd->cmd;
+	struct iommufd_device *idev;
+	const struct iommu_ops *ops;
+	int rc = 0;
+
+	idev = iommufd_get_device(ucmd, cmd->dev_id);
+	if (IS_ERR(idev))
+		return PTR_ERR(idev);
+
+	ops = dev_iommu_ops(idev->dev);
+	if (ops && ops->unset_rid_user)
+		rc = ops->unset_rid_user(idev->dev);
+	iommufd_put_object(&idev->obj);
+	return rc;
+}
+
 void iommufd_access_destroy_object(struct iommufd_object *obj)
 {
 	struct iommufd_access *access =
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index e52fd9d8c160..d65617727c0c 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -320,6 +320,8 @@ iommufd_get_device(struct iommufd_ucmd *ucmd, u32 id)
 
 void iommufd_device_destroy(struct iommufd_object *obj);
 int iommufd_device_get_hw_info(struct iommufd_ucmd *ucmd);
+int iommufd_device_set_rid(struct iommufd_ucmd *ucmd);
+int iommufd_device_unset_rid(struct iommufd_ucmd *ucmd);
 
 extern const u64 iommufd_hwpt_type_bitmaps[];
 
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index 7ec3ceac01b3..113fac4d4de0 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -317,6 +317,10 @@ static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
 		 val64),
 	IOCTL_OP(IOMMU_VFIO_IOAS, iommufd_vfio_ioas, struct iommu_vfio_ioas,
 		 __reserved),
+	IOCTL_OP(IOMMU_DEVICE_SET_RID, iommufd_device_set_rid,
+		 struct iommufd_device_set_rid, rid_base),
+	IOCTL_OP(IOMMU_DEVICE_UNSET_RID, iommufd_device_unset_rid,
+		 struct iommufd_device_unset_rid, dev_id),
 #ifdef CONFIG_IOMMUFD_TEST
 	IOCTL_OP(IOMMU_TEST_CMD, iommufd_test, struct iommu_test_cmd, last),
 #endif
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 59a44ceff27d..5188a4318e22 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -48,6 +48,8 @@ enum {
 	IOMMUFD_CMD_HWPT_ALLOC,
 	IOMMUFD_CMD_DEVICE_GET_HW_INFO,
 	IOMMUFD_CMD_HWPT_INVALIDATE,
+	IOMMUFD_CMD_DEVICE_SET_RID,
+	IOMMUFD_CMD_DEVICE_UNSET_RID,
 };
 
 /**
@@ -482,4 +484,33 @@ struct iommu_hwpt_invalidate {
 	__aligned_u64 data_uptr;
 };
 #define IOMMU_HWPT_INVALIDATE _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_INVALIDATE)
+
+/**
+ * struct iommufd_device_set_rid - ioctl(IOMMU_DEVICE_SET_RID)
+ * @size: sizeof(struct iommufd_device_set_rid)
+ * @dev_id: The device to set a Request ID
+ * @rid: PCI Request ID
+ *       Bits [15:8] are the Bus number.
+ *       Bits [7:3] are the Device number.
+ *       Bits [2:0] are the Function number.
+ * @rid_base: Base ID to map PCI Request ID
+ */
+struct iommufd_device_set_rid {
+	__u32 size;
+	__u32 dev_id;
+	__u32 rid;
+	__u32 rid_base;
+};
+#define IOMMU_DEVICE_SET_RID _IO(IOMMUFD_TYPE, IOMMUFD_CMD_DEVICE_SET_RID)
+
+/**
+ * struct iommufd_device_unset_rid - ioctl(IOMMU_DEVICE_UNSET_RID)
+ * @size: sizeof(struct iommufd_device_unset_rid)
+ * @dev_id: The device to unset a Request ID
+ */
+struct iommufd_device_unset_rid {
+	__u32 size;
+	__u32 dev_id;
+};
+#define IOMMU_DEVICE_UNSET_RID _IO(IOMMUFD_TYPE, IOMMUFD_CMD_DEVICE_UNSET_RID)
 #endif
-- 
2.40.0