On 2019/9/24 上午12:05, Alex Williamson wrote:

On Mon, 23 Sep 2019 21:03:26 +0800
Jason Wang [off-list ref] wrote:

quoted

Mdev bus only supports vfio driver right now, so it doesn't implement
match method. But in the future, we may add drivers other than vfio,
one example is virtio-mdev[1] driver. This means we need to add device
class id support in bus match method to pair the mdev device and mdev
driver correctly.

So this patch adds id_table to mdev_driver and class_id for mdev
parent with the match method for mdev bus.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 Documentation/driver-api/vfio-mediated-device.rst |  7 +++++--
 drivers/gpu/drm/i915/gvt/kvmgt.c                  |  2 +-
 drivers/s390/cio/vfio_ccw_ops.c                   |  2 +-
 drivers/s390/crypto/vfio_ap_ops.c                 |  3 ++-
 drivers/vfio/mdev/mdev_core.c                     | 14 ++++++++++++--
 drivers/vfio/mdev/mdev_driver.c                   | 14 ++++++++++++++
 drivers/vfio/mdev/mdev_private.h                  |  1 +
 drivers/vfio/mdev/vfio_mdev.c                     |  6 ++++++
 include/linux/mdev.h                              |  7 ++++++-
 include/linux/mod_devicetable.h                   |  8 ++++++++
 samples/vfio-mdev/mbochs.c                        |  2 +-
 samples/vfio-mdev/mdpy.c                          |  2 +-
 samples/vfio-mdev/mtty.c                          |  2 +-
 13 files changed, 59 insertions(+), 11 deletions(-)

diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
index 25eb7d5b834b..0e052072e1d8 100644
--- a/Documentation/driver-api/vfio-mediated-device.rst
+++ b/Documentation/driver-api/vfio-mediated-device.rst

@@ -102,12 +102,14 @@ structure to represent a mediated device's driver::
       * @probe: called when new device created
       * @remove: called when device removed
       * @driver: device driver structure
+      * @id_table: the ids serviced by this driver.
       */
      struct mdev_driver {
 	     const char *name;
 	     int  (*probe)  (struct device *dev);
 	     void (*remove) (struct device *dev);
 	     struct device_driver    driver;
+	     const struct mdev_class_id *id_table;
      };
 
 A mediated bus driver for mdev should use this structure in the function calls

@@ -116,7 +118,7 @@ to register and unregister itself with the core driver:
 * Register::
 
     extern int  mdev_register_driver(struct mdev_driver *drv,
-				   struct module *owner);
+                                     struct module *owner);
 
 * Unregister::
 

@@ -163,7 +165,8 @@ A driver should use the mdev_parent_ops structure in the function call to
 register itself with the mdev core driver::
 
 	extern int  mdev_register_device(struct device *dev,
-	                                 const struct mdev_parent_ops *ops);
+	                                 const struct mdev_parent_ops *ops,
+	                                 u8 class_id);
 
 However, the mdev_parent_ops structure is not required in the function call
 that a driver should use to unregister itself with the mdev core driver::

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 23aa3e50cbf8..19d51a35f019 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c

@@ -1625,7 +1625,7 @@ static int kvmgt_host_init(struct device *dev, void *gvt, const void *ops)
 		return -EFAULT;
 	intel_vgpu_ops.supported_type_groups = kvm_vgpu_type_groups;
 
-	return mdev_register_device(dev, &intel_vgpu_ops);
+	return mdev_register_vfio_device(dev, &intel_vgpu_ops);
 }
 
 static void kvmgt_host_exit(struct device *dev)

diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index f0d71ab77c50..246ff0f80944 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c

@@ -588,7 +588,7 @@ static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
 
 int vfio_ccw_mdev_reg(struct subchannel *sch)
 {
-	return mdev_register_device(&sch->dev, &vfio_ccw_mdev_ops);
+	return mdev_register_vfio_device(&sch->dev, &vfio_ccw_mdev_ops);
 }
 
 void vfio_ccw_mdev_unreg(struct subchannel *sch)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 5c0f53c6dde7..7487fc39d2c5 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c

@@ -1295,7 +1295,8 @@ int vfio_ap_mdev_register(void)
 {
 	atomic_set(&matrix_dev->available_instances, MAX_ZDEV_ENTRIES_EXT);
 
-	return mdev_register_device(&matrix_dev->device, &vfio_ap_matrix_ops);
+	return mdev_register_vfio_device(&matrix_dev->device,
+					 &vfio_ap_matrix_ops);
 }
 
 void vfio_ap_mdev_unregister(void)

diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index b558d4cfd082..a02c256a3514 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c

@@ -135,11 +135,14 @@ static int mdev_device_remove_cb(struct device *dev, void *data)
  * mdev_register_device : Register a device
  * @dev: device structure representing parent device.
  * @ops: Parent device operation structure to be registered.
+ * @id: device id.
  *
  * Add device to list of registered parent devices.
  * Returns a negative value on error, otherwise 0.
  */
-int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
+int mdev_register_device(struct device *dev,
+			 const struct mdev_parent_ops *ops,
+			 u8 class_id)
 {
 	int ret;
 	struct mdev_parent *parent;

@@ -175,6 +178,7 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
 
 	parent->dev = dev;
 	parent->ops = ops;
+	parent->class_id = class_id;
 

I don't think we want to tie the class_id to the parent.  mdev parent
devices can create various types of devices, some might be virtio, some
might be vfio.  I think the cover letter even suggests that's a
direction these virtio devices might be headed.  It seems the class
should be on the resulting device itself.  That also suggests that at
the parent we cannot have a single device_ops, the ops used will depend
on the type of device created.  Perhaps that means we need vfio_ops
alongside virtio_ops, rather than a common device_ops.  Thanks,

Alex

Yes, will do it in V2.

Thanks