[PATCH 0/6] mdev based hardware virtio offloading support

[PATCH 0/6] mdev based hardware virtio offloading support

[Jason Wang]

Hi all:

There are hardware that can do virtio datapath offloading while having
its own control path. This path tries to implement a mdev based
unified API to support using kernel virtio driver to drive those
devices. This is done by introducing a new mdev transport for virtio
(virtio_mdev) and register itself as a new kind of mdev driver. Then
it provides a unified way for kernel virtio driver to talk with mdev
device implementation.

Though the series only contains kernel driver support, the goal is to
make the transport generic enough to support userspace drivers. This
means vhost-mdev[1] could be built on top as well by resuing the
transport.

A sample driver is also implemented which simulate a virito-net
loopback ethernet device on top of vringh + workqueue. This could be
used as a reference implementation for real hardware driver.

Consider mdev framework only support VFIO device and driver right now,
this series also extend it to support other types. This is done
through introducing class id to the device and pairing it with
id_talbe claimed by the driver. On top, this seris also decouple
device specific parents ops out of the common ones.

Pktgen test was done with virito-net + mvnet loop back device.

Please review.

[1] https://lkml.org/lkml/2019/9/16/869

Changes from RFC-V2:
- silent compile warnings on some specific configuration
- use u16 instead u8 for class id
- reseve MDEV_ID_VHOST for future vhost-mdev work
- introduce "virtio" type for mvnet and make "vhost" type for future
  work
- add entries in MAINTAINER
- tweak and typos fixes in commit log

Changes from RFC-V1:

- rename device id to class id
- add docs for class id and device specific ops (device_ops)
- split device_ops into seperate headers
- drop the mdev_set_dma_ops()
- use device_ops to implement the transport API, then it's not a part
  of UAPI any more
- use GFP_ATOMIC in mvnet sample device and other tweaks
- set_vring_base/get_vring_base support for mvnet device

Jason Wang (6):
  mdev: class id support
  mdev: introduce device specific ops
  mdev: introduce virtio device and its device ops
  virtio: introduce a mdev based transport
  vringh: fix copy direction of vringh_iov_push_kern()
  docs: sample driver to demonstrate how to implement virtio-mdev
    framework

 .../driver-api/vfio-mediated-device.rst       |  11 +-
 MAINTAINERS                                   |   3 +
 drivers/gpu/drm/i915/gvt/kvmgt.c              |  17 +-
 drivers/s390/cio/vfio_ccw_ops.c               |  17 +-
 drivers/s390/crypto/vfio_ap_ops.c             |  14 +-
 drivers/vfio/mdev/Kconfig                     |   7 +
 drivers/vfio/mdev/Makefile                    |   1 +
 drivers/vfio/mdev/mdev_core.c                 |  21 +-
 drivers/vfio/mdev/mdev_driver.c               |  14 +
 drivers/vfio/mdev/mdev_private.h              |   1 +
 drivers/vfio/mdev/vfio_mdev.c                 |  37 +-
 drivers/vfio/mdev/virtio_mdev.c               | 416 +++++++++++
 drivers/vhost/vringh.c                        |   8 +-
 include/linux/mdev.h                          |  47 +-
 include/linux/mod_devicetable.h               |   8 +
 include/linux/vfio_mdev.h                     |  53 ++
 include/linux/virtio_mdev.h                   | 144 ++++
 samples/Kconfig                               |   7 +
 samples/vfio-mdev/Makefile                    |   1 +
 samples/vfio-mdev/mbochs.c                    |  19 +-
 samples/vfio-mdev/mdpy.c                      |  19 +-
 samples/vfio-mdev/mtty.c                      |  17 +-
 samples/vfio-mdev/mvnet.c                     | 688 ++++++++++++++++++
 23 files changed, 1481 insertions(+), 89 deletions(-)
 create mode 100644 drivers/vfio/mdev/virtio_mdev.c
 create mode 100644 include/linux/vfio_mdev.h
 create mode 100644 include/linux/virtio_mdev.h
 create mode 100644 samples/vfio-mdev/mvnet.c

-- 
2.19.1

[PATCH 1/6] mdev: class id support

[Jason Wang]

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;
 
 	if (!mdev_bus_compat_class) {
 		mdev_bus_compat_class = class_compat_register("mdev_bus");
@@ -208,7 +212,13 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
 		put_device(dev);
 	return ret;
 }
-EXPORT_SYMBOL(mdev_register_device);
+
+int mdev_register_vfio_device(struct device *dev,
+			      const struct mdev_parent_ops *ops)
+{
+	return mdev_register_device(dev, ops, MDEV_ID_VFIO);
+}
+EXPORT_SYMBOL(mdev_register_vfio_device);
 
 /*
  * mdev_unregister_device : Unregister a parent device
diff --git a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
index 0d3223aee20b..b70bbebc9dd3 100644
--- a/drivers/vfio/mdev/mdev_driver.c
+++ b/drivers/vfio/mdev/mdev_driver.c
@@ -69,8 +69,22 @@ static int mdev_remove(struct device *dev)
 	return 0;
 }
 
+static int mdev_match(struct device *dev, struct device_driver *drv)
+{
+	unsigned int i;
+	struct mdev_device *mdev = to_mdev_device(dev);
+	struct mdev_driver *mdrv = to_mdev_driver(drv);
+	const struct mdev_class_id *ids = mdrv->id_table;
+
+	for (i = 0; ids[i].id; i++)
+		if (ids[i].id == mdev->parent->class_id)
+			return 1;
+	return 0;
+}
+
 struct bus_type mdev_bus_type = {
 	.name		= "mdev",
+	.match		= mdev_match,
 	.probe		= mdev_probe,
 	.remove		= mdev_remove,
 };
diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
index 7d922950caaf..e58b07c866b1 100644
--- a/drivers/vfio/mdev/mdev_private.h
+++ b/drivers/vfio/mdev/mdev_private.h
@@ -22,6 +22,7 @@ struct mdev_parent {
 	struct list_head type_list;
 	/* Synchronize device creation/removal with parent unregistration */
 	struct rw_semaphore unreg_sem;
+	u8 class_id;
 };
 
 struct mdev_device {
diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
index 30964a4e0a28..fd2a4d9a3f26 100644
--- a/drivers/vfio/mdev/vfio_mdev.c
+++ b/drivers/vfio/mdev/vfio_mdev.c
@@ -120,10 +120,16 @@ static void vfio_mdev_remove(struct device *dev)
 	vfio_del_group_dev(dev);
 }
 
+static struct mdev_class_id id_table[] = {
+	{ MDEV_ID_VFIO },
+	{ 0 },
+};
+
 static struct mdev_driver vfio_mdev_driver = {
 	.name	= "vfio_mdev",
 	.probe	= vfio_mdev_probe,
 	.remove	= vfio_mdev_remove,
+	.id_table = id_table,
 };
 
 static int __init vfio_mdev_init(void)
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 0ce30ca78db0..3ebae310f599 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -118,6 +118,7 @@ struct mdev_type_attribute mdev_type_attr_##_name =		\
  * @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 {
@@ -125,6 +126,7 @@ struct mdev_driver {
 	int  (*probe)(struct device *dev);
 	void (*remove)(struct device *dev);
 	struct device_driver driver;
+	const struct mdev_class_id *id_table;
 };
 
 #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
@@ -135,7 +137,8 @@ const guid_t *mdev_uuid(struct mdev_device *mdev);
 
 extern struct bus_type mdev_bus_type;
 
-int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops);
+int mdev_register_vfio_device(struct device *dev,
+			      const struct mdev_parent_ops *ops);
 void mdev_unregister_device(struct device *dev);
 
 int mdev_register_driver(struct mdev_driver *drv, struct module *owner);
@@ -145,4 +148,6 @@ struct device *mdev_parent_dev(struct mdev_device *mdev);
 struct device *mdev_dev(struct mdev_device *mdev);
 struct mdev_device *mdev_from_dev(struct device *dev);
 
+#define MDEV_ID_VFIO 1 /* VFIO device */
+
 #endif /* MDEV_H */
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 5714fd35a83c..f32c6e44fb1a 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -821,4 +821,12 @@ struct wmi_device_id {
 	const void *context;
 };
 
+/**
+ * struct mdev_class_id - MDEV device class identifier
+ * @id: Used to identify a specific class of device, e.g vfio-mdev device.
+ */
+struct mdev_class_id {
+	__u16 id;
+};
+
 #endif /* LINUX_MOD_DEVICETABLE_H */
diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index ac5c8c17b1ff..71a4469be85d 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -1468,7 +1468,7 @@ static int __init mbochs_dev_init(void)
 	if (ret)
 		goto failed2;
 
-	ret = mdev_register_device(&mbochs_dev, &mdev_fops);
+	ret = mdev_register_vfio_device(&mbochs_dev, &mdev_fops);
 	if (ret)
 		goto failed3;
 
diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
index cc86bf6566e4..d3029dd27d91 100644
--- a/samples/vfio-mdev/mdpy.c
+++ b/samples/vfio-mdev/mdpy.c
@@ -775,7 +775,7 @@ static int __init mdpy_dev_init(void)
 	if (ret)
 		goto failed2;
 
-	ret = mdev_register_device(&mdpy_dev, &mdev_fops);
+	ret = mdev_register_vfio_device(&mdpy_dev, &mdev_fops);
 	if (ret)
 		goto failed3;
 
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index 92e770a06ea2..744c88a6b22c 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -1468,7 +1468,7 @@ static int __init mtty_dev_init(void)
 	if (ret)
 		goto failed2;
 
-	ret = mdev_register_device(&mtty_dev.dev, &mdev_fops);
+	ret = mdev_register_vfio_device(&mtty_dev.dev, &mdev_fops);
 	if (ret)
 		goto failed3;
 
-- 
2.19.1

[PATCH 2/6] mdev: introduce device specific ops

[Jason Wang]

Currently, except for the create and remove. The rest of
mdev_parent_ops is designed for vfio-mdev driver only and may not help
for kernel mdev driver. Follow the class id support by previous patch,
this patch introduces device specific ops pointer inside parent ops
which points to device specific ops (e.g vfio ops). This allows the
future drivers like virtio-mdev to implement its own device specific
ops.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 .../driver-api/vfio-mediated-device.rst       |  4 +-
 MAINTAINERS                                   |  1 +
 drivers/gpu/drm/i915/gvt/kvmgt.c              | 15 +++---
 drivers/s390/cio/vfio_ccw_ops.c               | 15 ++++--
 drivers/s390/crypto/vfio_ap_ops.c             | 11 ++--
 drivers/vfio/mdev/vfio_mdev.c                 | 31 ++++++-----
 include/linux/mdev.h                          | 36 ++-----------
 include/linux/vfio_mdev.h                     | 53 +++++++++++++++++++
 samples/vfio-mdev/mbochs.c                    | 17 +++---
 samples/vfio-mdev/mdpy.c                      | 17 +++---
 samples/vfio-mdev/mtty.c                      | 15 ++++--
 11 files changed, 138 insertions(+), 77 deletions(-)
 create mode 100644 include/linux/vfio_mdev.h

diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
index 0e052072e1d8..3ab00e48212f 100644
--- a/Documentation/driver-api/vfio-mediated-device.rst
+++ b/Documentation/driver-api/vfio-mediated-device.rst
@@ -152,7 +152,9 @@ callbacks per mdev parent device, per mdev type, or any other categorization.
 Vendor drivers are expected to be fully asynchronous in this respect or
 provide their own internal resource protection.)
 
-The callbacks in the mdev_parent_ops structure are as follows:
+The device specific callbacks are referred through device_ops pointer
+in mdev_parent_ops. For vfio-mdev device, its callbacks in device_ops
+are as follows:
 
 * open: open callback of mediated device
 * close: close callback of mediated device
diff --git a/MAINTAINERS b/MAINTAINERS
index b2326dece28e..89832b316500 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17075,6 +17075,7 @@ S:	Maintained
 F:	Documentation/driver-api/vfio-mediated-device.rst
 F:	drivers/vfio/mdev/
 F:	include/linux/mdev.h
+F:	include/linux/vfio_mdev.h
 F:	samples/vfio-mdev/
 
 VFIO PLATFORM DRIVER
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 19d51a35f019..8ea86b1e69f1 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -42,6 +42,7 @@
 #include <linux/kvm_host.h>
 #include <linux/vfio.h>
 #include <linux/mdev.h>
+#include <linux/vfio_mdev.h>
 #include <linux/debugfs.h>
 
 #include <linux/nospec.h>
@@ -1600,20 +1601,22 @@ static const struct attribute_group *intel_vgpu_groups[] = {
 	NULL,
 };
 
-static struct mdev_parent_ops intel_vgpu_ops = {
-	.mdev_attr_groups       = intel_vgpu_groups,
-	.create			= intel_vgpu_create,
-	.remove			= intel_vgpu_remove,
-
+static struct vfio_mdev_parent_ops intel_vfio_vgpu_ops = {
 	.open			= intel_vgpu_open,
 	.release		= intel_vgpu_release,
-
 	.read			= intel_vgpu_read,
 	.write			= intel_vgpu_write,
 	.mmap			= intel_vgpu_mmap,
 	.ioctl			= intel_vgpu_ioctl,
 };
 
+static struct mdev_parent_ops intel_vgpu_ops = {
+	.mdev_attr_groups       = intel_vgpu_groups,
+	.create			= intel_vgpu_create,
+	.remove			= intel_vgpu_remove,
+	.device_ops	        = &intel_vfio_vgpu_ops,
+};
+
 static int kvmgt_host_init(struct device *dev, void *gvt, const void *ops)
 {
 	struct attribute **kvm_type_attrs;
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 246ff0f80944..02122bbc213e 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -12,6 +12,7 @@
 
 #include <linux/vfio.h>
 #include <linux/mdev.h>
+#include <linux/vfio_mdev.h>
 #include <linux/nospec.h>
 #include <linux/slab.h>
 
@@ -574,11 +575,7 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
 	}
 }
 
-static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
-	.owner			= THIS_MODULE,
-	.supported_type_groups  = mdev_type_groups,
-	.create			= vfio_ccw_mdev_create,
-	.remove			= vfio_ccw_mdev_remove,
+static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
 	.open			= vfio_ccw_mdev_open,
 	.release		= vfio_ccw_mdev_release,
 	.read			= vfio_ccw_mdev_read,
@@ -586,6 +583,14 @@ static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
 	.ioctl			= vfio_ccw_mdev_ioctl,
 };
 
+static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
+	.owner			= THIS_MODULE,
+	.supported_type_groups  = mdev_type_groups,
+	.create			= vfio_ccw_mdev_create,
+	.remove			= vfio_ccw_mdev_remove,
+	.device_ops		= &vfio_mdev_ops,
+};
+
 int vfio_ccw_mdev_reg(struct subchannel *sch)
 {
 	return mdev_register_vfio_device(&sch->dev, &vfio_ccw_mdev_ops);
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 7487fc39d2c5..4251becc7a6d 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -16,6 +16,7 @@
 #include <linux/bitops.h>
 #include <linux/kvm_host.h>
 #include <linux/module.h>
+#include <linux/vfio_mdev.h>
 #include <asm/kvm.h>
 #include <asm/zcrypt.h>
 
@@ -1280,15 +1281,19 @@ static ssize_t vfio_ap_mdev_ioctl(struct mdev_device *mdev,
 	return ret;
 }
 
+static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
+	.open			= vfio_ap_mdev_open,
+	.release		= vfio_ap_mdev_release,
+	.ioctl			= vfio_ap_mdev_ioctl,
+};
+
 static const struct mdev_parent_ops vfio_ap_matrix_ops = {
 	.owner			= THIS_MODULE,
 	.supported_type_groups	= vfio_ap_mdev_type_groups,
 	.mdev_attr_groups	= vfio_ap_mdev_attr_groups,
 	.create			= vfio_ap_mdev_create,
 	.remove			= vfio_ap_mdev_remove,
-	.open			= vfio_ap_mdev_open,
-	.release		= vfio_ap_mdev_release,
-	.ioctl			= vfio_ap_mdev_ioctl,
+	.device_ops		= &vfio_mdev_ops,
 };
 
 int vfio_ap_mdev_register(void)
diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
index fd2a4d9a3f26..d23c9f58c84f 100644
--- a/drivers/vfio/mdev/vfio_mdev.c
+++ b/drivers/vfio/mdev/vfio_mdev.c
@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/vfio.h>
 #include <linux/mdev.h>
+#include <linux/vfio_mdev.h>
 
 #include "mdev_private.h"
 
@@ -25,15 +26,16 @@ static int vfio_mdev_open(void *device_data)
 {
 	struct mdev_device *mdev = device_data;
 	struct mdev_parent *parent = mdev->parent;
+	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
 	int ret;
 
-	if (unlikely(!parent->ops->open))
+	if (unlikely(!ops->open))
 		return -EINVAL;
 
 	if (!try_module_get(THIS_MODULE))
 		return -ENODEV;
 
-	ret = parent->ops->open(mdev);
+	ret = ops->open(mdev);
 	if (ret)
 		module_put(THIS_MODULE);
 
@@ -44,9 +46,10 @@ static void vfio_mdev_release(void *device_data)
 {
 	struct mdev_device *mdev = device_data;
 	struct mdev_parent *parent = mdev->parent;
+	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
 
-	if (likely(parent->ops->release))
-		parent->ops->release(mdev);
+	if (likely(ops->release))
+		ops->release(mdev);
 
 	module_put(THIS_MODULE);
 }
@@ -56,11 +59,12 @@ static long vfio_mdev_unlocked_ioctl(void *device_data,
 {
 	struct mdev_device *mdev = device_data;
 	struct mdev_parent *parent = mdev->parent;
+	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
 
-	if (unlikely(!parent->ops->ioctl))
+	if (unlikely(!ops->ioctl))
 		return -EINVAL;
 
-	return parent->ops->ioctl(mdev, cmd, arg);
+	return ops->ioctl(mdev, cmd, arg);
 }
 
 static ssize_t vfio_mdev_read(void *device_data, char __user *buf,
@@ -68,11 +72,12 @@ static ssize_t vfio_mdev_read(void *device_data, char __user *buf,
 {
 	struct mdev_device *mdev = device_data;
 	struct mdev_parent *parent = mdev->parent;
+	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
 
-	if (unlikely(!parent->ops->read))
+	if (unlikely(!ops->read))
 		return -EINVAL;
 
-	return parent->ops->read(mdev, buf, count, ppos);
+	return ops->read(mdev, buf, count, ppos);
 }
 
 static ssize_t vfio_mdev_write(void *device_data, const char __user *buf,
@@ -80,22 +85,24 @@ static ssize_t vfio_mdev_write(void *device_data, const char __user *buf,
 {
 	struct mdev_device *mdev = device_data;
 	struct mdev_parent *parent = mdev->parent;
+	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
 
-	if (unlikely(!parent->ops->write))
+	if (unlikely(!ops->write))
 		return -EINVAL;
 
-	return parent->ops->write(mdev, buf, count, ppos);
+	return ops->write(mdev, buf, count, ppos);
 }
 
 static int vfio_mdev_mmap(void *device_data, struct vm_area_struct *vma)
 {
 	struct mdev_device *mdev = device_data;
 	struct mdev_parent *parent = mdev->parent;
+	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
 
-	if (unlikely(!parent->ops->mmap))
+	if (unlikely(!ops->mmap))
 		return -EINVAL;
 
-	return parent->ops->mmap(mdev, vma);
+	return ops->mmap(mdev, vma);
 }
 
 static const struct vfio_device_ops vfio_mdev_dev_ops = {
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 3ebae310f599..fa167bcb81e1 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -48,30 +48,8 @@ struct device *mdev_get_iommu_device(struct device *dev);
  *			@mdev: mdev_device device structure which is being
  *			       destroyed
  *			Returns integer: success (0) or error (< 0)
- * @open:		Open mediated device.
- *			@mdev: mediated device.
- *			Returns integer: success (0) or error (< 0)
- * @release:		release mediated device
- *			@mdev: mediated device.
- * @read:		Read emulation callback
- *			@mdev: mediated device structure
- *			@buf: read buffer
- *			@count: number of bytes to read
- *			@ppos: address.
- *			Retuns number on bytes read on success or error.
- * @write:		Write emulation callback
- *			@mdev: mediated device structure
- *			@buf: write buffer
- *			@count: number of bytes to be written
- *			@ppos: address.
- *			Retuns number on bytes written on success or error.
- * @ioctl:		IOCTL callback
- *			@mdev: mediated device structure
- *			@cmd: ioctl command
- *			@arg: arguments to ioctl
- * @mmap:		mmap callback
- *			@mdev: mediated device structure
- *			@vma: vma structure
+ * @device_ops:         Device specific emulation callback.
+ *
  * Parent device that support mediated device should be registered with mdev
  * module with mdev_parent_ops structure.
  **/
@@ -83,15 +61,7 @@ struct mdev_parent_ops {
 
 	int     (*create)(struct kobject *kobj, struct mdev_device *mdev);
 	int     (*remove)(struct mdev_device *mdev);
-	int     (*open)(struct mdev_device *mdev);
-	void    (*release)(struct mdev_device *mdev);
-	ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
-			size_t count, loff_t *ppos);
-	ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
-			 size_t count, loff_t *ppos);
-	long	(*ioctl)(struct mdev_device *mdev, unsigned int cmd,
-			 unsigned long arg);
-	int	(*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
+	const void *device_ops;
 };
 
 /* interface for exporting mdev supported type attributes */
diff --git a/include/linux/vfio_mdev.h b/include/linux/vfio_mdev.h
new file mode 100644
index 000000000000..0c1b34f98f5d
--- /dev/null
+++ b/include/linux/vfio_mdev.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * VFIO Mediated device definition
+ */
+
+#ifndef VFIO_MDEV_H
+#define VFIO_MDEV_H
+
+#include <linux/types.h>
+#include <linux/mdev.h>
+
+/**
+ * struct vfio_mdev_parent_ops - Structure to be registered for each
+ * parent device to register the device to vfio-mdev module.
+ *
+ * @open:		Open mediated device.
+ *			@mdev: mediated device.
+ *			Returns integer: success (0) or error (< 0)
+ * @release:		release mediated device
+ *			@mdev: mediated device.
+ * @read:		Read emulation callback
+ *			@mdev: mediated device structure
+ *			@buf: read buffer
+ *			@count: number of bytes to read
+ *			@ppos: address.
+ *			Retuns number on bytes read on success or error.
+ * @write:		Write emulation callback
+ *			@mdev: mediated device structure
+ *			@buf: write buffer
+ *			@count: number of bytes to be written
+ *			@ppos: address.
+ *			Retuns number on bytes written on success or error.
+ * @ioctl:		IOCTL callback
+ *			@mdev: mediated device structure
+ *			@cmd: ioctl command
+ *			@arg: arguments to ioctl
+ * @mmap:		mmap callback
+ *			@mdev: mediated device structure
+ *			@vma: vma structure
+ */
+struct vfio_mdev_parent_ops {
+	int     (*open)(struct mdev_device *mdev);
+	void    (*release)(struct mdev_device *mdev);
+	ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
+			size_t count, loff_t *ppos);
+	ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
+			 size_t count, loff_t *ppos);
+	long	(*ioctl)(struct mdev_device *mdev, unsigned int cmd,
+			 unsigned long arg);
+	int	(*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
+};
+
+#endif
diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index 71a4469be85d..107cc30d0f45 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -30,6 +30,7 @@
 #include <linux/iommu.h>
 #include <linux/sysfs.h>
 #include <linux/mdev.h>
+#include <linux/vfio_mdev.h>
 #include <linux/pci.h>
 #include <linux/dma-buf.h>
 #include <linux/highmem.h>
@@ -1418,12 +1419,7 @@ static struct attribute_group *mdev_type_groups[] = {
 	NULL,
 };
 
-static const struct mdev_parent_ops mdev_fops = {
-	.owner			= THIS_MODULE,
-	.mdev_attr_groups	= mdev_dev_groups,
-	.supported_type_groups	= mdev_type_groups,
-	.create			= mbochs_create,
-	.remove			= mbochs_remove,
+static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
 	.open			= mbochs_open,
 	.release		= mbochs_close,
 	.read			= mbochs_read,
@@ -1432,6 +1428,15 @@ static const struct mdev_parent_ops mdev_fops = {
 	.mmap			= mbochs_mmap,
 };
 
+static const struct mdev_parent_ops mdev_fops = {
+	.owner			= THIS_MODULE,
+	.mdev_attr_groups	= mdev_dev_groups,
+	.supported_type_groups	= mdev_type_groups,
+	.create			= mbochs_create,
+	.remove			= mbochs_remove,
+	.device_ops		= &vfio_mdev_ops,
+};
+
 static const struct file_operations vd_fops = {
 	.owner		= THIS_MODULE,
 };
diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
index d3029dd27d91..2cd2018a53f9 100644
--- a/samples/vfio-mdev/mdpy.c
+++ b/samples/vfio-mdev/mdpy.c
@@ -26,6 +26,7 @@
 #include <linux/iommu.h>
 #include <linux/sysfs.h>
 #include <linux/mdev.h>
+#include <linux/vfio_mdev.h>
 #include <linux/pci.h>
 #include <drm/drm_fourcc.h>
 #include "mdpy-defs.h"
@@ -725,12 +726,7 @@ static struct attribute_group *mdev_type_groups[] = {
 	NULL,
 };
 
-static const struct mdev_parent_ops mdev_fops = {
-	.owner			= THIS_MODULE,
-	.mdev_attr_groups	= mdev_dev_groups,
-	.supported_type_groups	= mdev_type_groups,
-	.create			= mdpy_create,
-	.remove			= mdpy_remove,
+static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
 	.open			= mdpy_open,
 	.release		= mdpy_close,
 	.read			= mdpy_read,
@@ -739,6 +735,15 @@ static const struct mdev_parent_ops mdev_fops = {
 	.mmap			= mdpy_mmap,
 };
 
+static const struct mdev_parent_ops mdev_fops = {
+	.owner			= THIS_MODULE,
+	.mdev_attr_groups	= mdev_dev_groups,
+	.supported_type_groups	= mdev_type_groups,
+	.create			= mdpy_create,
+	.remove			= mdpy_remove,
+	.device_ops		= &vfio_mdev_ops,
+};
+
 static const struct file_operations vd_fops = {
 	.owner		= THIS_MODULE,
 };
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index 744c88a6b22c..e427425b5daf 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -27,6 +27,7 @@
 #include <linux/ctype.h>
 #include <linux/file.h>
 #include <linux/mdev.h>
+#include <linux/vfio_mdev.h>
 #include <linux/pci.h>
 #include <linux/serial.h>
 #include <uapi/linux/serial_reg.h>
@@ -1410,6 +1411,14 @@ static struct attribute_group *mdev_type_groups[] = {
 	NULL,
 };
 
+static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
+	.open                   = mtty_open,
+	.release                = mtty_close,
+	.read                   = mtty_read,
+	.write                  = mtty_write,
+	.ioctl		        = mtty_ioctl,
+};
+
 static const struct mdev_parent_ops mdev_fops = {
 	.owner                  = THIS_MODULE,
 	.dev_attr_groups        = mtty_dev_groups,
@@ -1417,11 +1426,7 @@ static const struct mdev_parent_ops mdev_fops = {
 	.supported_type_groups  = mdev_type_groups,
 	.create                 = mtty_create,
 	.remove			= mtty_remove,
-	.open                   = mtty_open,
-	.release                = mtty_close,
-	.read                   = mtty_read,
-	.write                  = mtty_write,
-	.ioctl		        = mtty_ioctl,
+	.device_ops             = &vfio_mdev_ops,
 };
 
 static void mtty_device_release(struct device *dev)
-- 
2.19.1

[PATCH 3/6] mdev: introduce virtio device and its device ops

[Jason Wang]

This patch implements basic support for mdev driver that supports
virtio transport for kernel virtio driver.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vfio/mdev/mdev_core.c |   7 ++
 include/linux/mdev.h          |   4 +
 include/linux/virtio_mdev.h   | 144 ++++++++++++++++++++++++++++++++++
 3 files changed, 155 insertions(+)
 create mode 100644 include/linux/virtio_mdev.h

diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index a02c256a3514..6d39caf96222 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -220,6 +220,13 @@ int mdev_register_vfio_device(struct device *dev,
 }
 EXPORT_SYMBOL(mdev_register_vfio_device);
 
+int mdev_register_virtio_device(struct device *dev,
+				const struct mdev_parent_ops *ops)
+{
+	return mdev_register_device(dev, ops, MDEV_ID_VIRTIO);
+}
+EXPORT_SYMBOL(mdev_register_virtio_device);
+
 /*
  * mdev_unregister_device : Unregister a parent device
  * @dev: device structure representing parent device.
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index fa167bcb81e1..1d061739021e 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -109,6 +109,8 @@ extern struct bus_type mdev_bus_type;
 
 int mdev_register_vfio_device(struct device *dev,
 			      const struct mdev_parent_ops *ops);
+int mdev_register_virtio_device(struct device *dev,
+				const struct mdev_parent_ops *ops);
 void mdev_unregister_device(struct device *dev);
 
 int mdev_register_driver(struct mdev_driver *drv, struct module *owner);
@@ -119,5 +121,7 @@ struct device *mdev_dev(struct mdev_device *mdev);
 struct mdev_device *mdev_from_dev(struct device *dev);
 
 #define MDEV_ID_VFIO 1 /* VFIO device */
+#define MDEV_ID_VIRTIO 2 /* Virtio Device */
+#define MDEV_ID_VHOST 3 /* Vhost Device */
 
 #endif /* MDEV_H */
diff --git a/include/linux/virtio_mdev.h b/include/linux/virtio_mdev.h
new file mode 100644
index 000000000000..f8db03c93d36
--- /dev/null
+++ b/include/linux/virtio_mdev.h
@@ -0,0 +1,144 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Virtio mediated device driver
+ *
+ * Copyright 2019, Red Hat Corp.
+ *     Author: Jason Wang <jasowang@redhat.com>
+ */
+#ifndef _LINUX_VIRTIO_MDEV_H
+#define _LINUX_VIRTIO_MDEV_H
+
+#include <linux/interrupt.h>
+#include <uapi/linux/vhost.h>
+
+#define VIRTIO_MDEV_DEVICE_API_STRING		"virtio-mdev"
+#define VIRTIO_MDEV_VERSION 0x1
+
+struct virtio_mdev_callback {
+	irqreturn_t (*callback)(void *data);
+	void *private;
+};
+
+/**
+ * struct vfio_mdev_parent_ops - Structure to be registered for each
+ * parent device to register the device to virtio-mdev module.
+ *
+ * @set_vq_address:		Set the address of virtqueue
+ *				@mdev: mediated device
+ *				@idx: virtqueue index
+ *				@desc_area: address of desc area
+ *				@driver_area: address of driver area
+ *				@device_area: address of device area
+ *				Returns integer: success (0) or error (< 0)
+ * @set_vq_num:		Set the size of virtqueue
+ *				@mdev: mediated device
+ *				@idx: virtqueue index
+ *				@num: the size of virtqueue
+ * @kick_vq:			Kick the virtqueue
+ *				@mdev: mediated device
+ *				@idx: virtqueue index
+ * @set_vq_cb:			Set the interrut calback function for
+ *				a virtqueue
+ *				@mdev: mediated device
+ *				@idx: virtqueue index
+ *				@cb: virtio-mdev interrupt callback structure
+ * @set_vq_ready:		Set ready status for a virtqueue
+ *				@mdev: mediated device
+ *				@idx: virtqueue index
+ *				@ready: ready (true) not ready(false)
+ * @get_vq_ready:		Get ready status for a virtqueue
+ *				@mdev: mediated device
+ *				@idx: virtqueue index
+ *				Returns boolean: ready (true) or not (false)
+ * @set_vq_state:		Set the state for a virtqueue
+ *				@mdev: mediated device
+ *				@idx: virtqueue index
+ *				@state: virtqueue state (last_avail_idx)
+ *				Returns integer: success (0) or error (< 0)
+ * @get_vq_state:		Get the state for a virtqueue
+ *				@mdev: mediated device
+ *				@idx: virtqueue index
+ *				Returns virtqueue state (last_avail_idx)
+ * @get_vq_align:		Get the virtqueue align requirement
+ *				for the device
+ *				@mdev: mediated device
+ *				Returns virtqueue algin requirement
+ * @get_features:		Get virtio features supported by the device
+ *				@mdev: mediated device
+ *				Returns the features support by the
+ *				device
+ * @get_features:		Set virtio features supported by the driver
+ *				@mdev: mediated device
+ *				@features: feature support by the driver
+ *				Returns integer: success (0) or error (< 0)
+ * @set_config_cb:		Set the config interrupt callback
+ *				@mdev: mediated device
+ *				@cb: virtio-mdev interrupt callback structure
+ * @get_device_id:		Get virtio device id
+ *				@mdev: mediated device
+ *				Returns u32: virtio device id
+ * @get_vendor_id:		Get virtio vendor id
+ *				@mdev: mediated device
+ *				Returns u32: virtio vendor id
+ * @get_status:		Get the device status
+ *				@mdev: mediated device
+ *				Returns u8: virtio device status
+ * @set_status:		Set the device status
+ *				@mdev: mediated device
+ *				@status: virtio device status
+ * @get_config:		Read from device specific confiugration space
+ *				@mdev: mediated device
+ *				@offset: offset from the beginning of
+ *				configuration space
+ *				@buf: buffer used to read to
+ *				@len: the length to read from
+ *				configration space
+ * @set_config:		Write to device specific confiugration space
+ *				@mdev: mediated device
+ *				@offset: offset from the beginning of
+ *				configuration space
+ *				@buf: buffer used to write from
+ *				@len: the length to write to
+ *				configration space
+ * @get_version:		Get the version of virtio mdev device
+ *				@mdev: mediated device
+ *				Returns integer: version of the device
+ * @get_generation:		Get device generaton
+ *				@mdev: mediated device
+ *				Returns u32: device generation
+ */
+struct virtio_mdev_parent_ops {
+	/* Virtqueue ops */
+	int (*set_vq_address)(struct mdev_device *mdev,
+			      u16 idx, u64 desc_area, u64 driver_area,
+			      u64 device_area);
+	void (*set_vq_num)(struct mdev_device *mdev, u16 idx, u32 num);
+	void (*kick_vq)(struct mdev_device *mdev, u16 idx);
+	void (*set_vq_cb)(struct mdev_device *mdev, u16 idx,
+			  struct virtio_mdev_callback *cb);
+	void (*set_vq_ready)(struct mdev_device *mdev, u16 idx, bool ready);
+	bool (*get_vq_ready)(struct mdev_device *mdev, u16 idx);
+	int (*set_vq_state)(struct mdev_device *mdev, u16 idx, u64 state);
+	u64 (*get_vq_state)(struct mdev_device *mdev, u16 idx);
+
+	/* Device ops */
+	u16 (*get_vq_align)(struct mdev_device *mdev);
+	u64 (*get_features)(struct mdev_device *mdev);
+	int (*set_features)(struct mdev_device *mdev, u64 features);
+	void (*set_config_cb)(struct mdev_device *mdev,
+			      struct virtio_mdev_callback *cb);
+	u16 (*get_queue_max)(struct mdev_device *mdev);
+	u32 (*get_device_id)(struct mdev_device *mdev);
+	u32 (*get_vendor_id)(struct mdev_device *mdev);
+	u8 (*get_status)(struct mdev_device *mdev);
+	void (*set_status)(struct mdev_device *mdev, u8 status);
+	void (*get_config)(struct mdev_device *mdev, unsigned int offset,
+			   void *buf, unsigned int len);
+	void (*set_config)(struct mdev_device *mdev, unsigned int offset,
+			   const void *buf, unsigned int len);
+	int (*get_version)(struct mdev_device *mdev);
+	u32 (*get_generation)(struct mdev_device *mdev);
+};
+
+#endif
+
-- 
2.19.1

[PATCH 4/6] virtio: introduce a mdev based transport

[Jason Wang]

This patch introduces a new mdev transport for virtio. This is used to
use kernel virtio driver to drive the mediated device that is capable
of populating virtqueue directly.

A new virtio-mdev driver will be registered to the mdev bus, when a
new virtio-mdev device is probed, it will register the device with
mdev based config ops. This means it is a software transport between
mdev driver and mdev device. The transport was implemented through
device specific opswhich is a part of mdev_parent_ops now.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 MAINTAINERS                     |   1 +
 drivers/vfio/mdev/Kconfig       |   7 +
 drivers/vfio/mdev/Makefile      |   1 +
 drivers/vfio/mdev/virtio_mdev.c | 416 ++++++++++++++++++++++++++++++++
 4 files changed, 425 insertions(+)
 create mode 100644 drivers/vfio/mdev/virtio_mdev.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 89832b316500..820ec250cc52 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17202,6 +17202,7 @@ F:	include/linux/virtio*.h
 F:	include/uapi/linux/virtio_*.h
 F:	drivers/crypto/virtio/
 F:	mm/balloon_compaction.c
+F:	drivers/vfio/mdev/virtio_mdev.c
 
 VIRTIO BLOCK AND SCSI DRIVERS
 M:	"Michael S. Tsirkin" <mst@redhat.com>
diff --git a/drivers/vfio/mdev/Kconfig b/drivers/vfio/mdev/Kconfig
index 5da27f2100f9..c488c31fc137 100644
--- a/drivers/vfio/mdev/Kconfig
+++ b/drivers/vfio/mdev/Kconfig
@@ -16,3 +16,10 @@ config VFIO_MDEV_DEVICE
 	default n
 	help
 	  VFIO based driver for Mediated devices.
+
+config VIRTIO_MDEV_DEVICE
+	tristate "VIRTIO driver for Mediated devices"
+	depends on VFIO_MDEV && VIRTIO
+	default n
+	help
+	  VIRTIO based driver for Mediated devices.
diff --git a/drivers/vfio/mdev/Makefile b/drivers/vfio/mdev/Makefile
index 101516fdf375..99d31e29c23e 100644
--- a/drivers/vfio/mdev/Makefile
+++ b/drivers/vfio/mdev/Makefile
@@ -4,3 +4,4 @@ mdev-y := mdev_core.o mdev_sysfs.o mdev_driver.o
 
 obj-$(CONFIG_VFIO_MDEV) += mdev.o
 obj-$(CONFIG_VFIO_MDEV_DEVICE) += vfio_mdev.o
+obj-$(CONFIG_VIRTIO_MDEV_DEVICE) += virtio_mdev.o
diff --git a/drivers/vfio/mdev/virtio_mdev.c b/drivers/vfio/mdev/virtio_mdev.c
new file mode 100644
index 000000000000..919a082adc9c
--- /dev/null
+++ b/drivers/vfio/mdev/virtio_mdev.c
@@ -0,0 +1,416 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * VIRTIO based driver for Mediated device
+ *
+ * Copyright (c) 2019, Red Hat. All rights reserved.
+ *     Author: Jason Wang <jasowang@redhat.com>
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/uuid.h>
+#include <linux/mdev.h>
+#include <linux/virtio_mdev.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_ring.h>
+#include "mdev_private.h"
+
+#define DRIVER_VERSION  "0.1"
+#define DRIVER_AUTHOR   "Red Hat Corporation"
+#define DRIVER_DESC     "VIRTIO based driver for Mediated device"
+
+#define to_virtio_mdev_device(dev) \
+	container_of(dev, struct virtio_mdev_device, vdev)
+
+struct virtio_mdev_device {
+	struct virtio_device vdev;
+	struct mdev_device *mdev;
+	unsigned long version;
+
+	struct virtqueue **vqs;
+	spinlock_t lock;
+};
+
+struct virtio_mdev_vq_info {
+	/* the actual virtqueue */
+	struct virtqueue *vq;
+
+	/* the list node for the virtqueues list */
+	struct list_head node;
+};
+
+static struct mdev_device *vm_get_mdev(struct virtio_device *vdev)
+{
+	struct virtio_mdev_device *vm_dev = to_virtio_mdev_device(vdev);
+	struct mdev_device *mdev = vm_dev->mdev;
+
+	return mdev;
+}
+
+static const struct virtio_mdev_parent_ops
+*mdev_get_parent_ops(struct mdev_device *mdev)
+{
+	struct mdev_parent *parent = mdev->parent;
+
+	return parent->ops->device_ops;
+}
+
+static void virtio_mdev_get(struct virtio_device *vdev, unsigned offset,
+			    void *buf, unsigned len)
+{
+	struct mdev_device *mdev = vm_get_mdev(vdev);
+	const struct virtio_mdev_parent_ops *ops = mdev_get_parent_ops(mdev);
+
+	ops->get_config(mdev, offset, buf, len);
+}
+
+static void virtio_mdev_set(struct virtio_device *vdev, unsigned offset,
+			    const void *buf, unsigned len)
+{
+	struct mdev_device *mdev = vm_get_mdev(vdev);
+	const struct virtio_mdev_parent_ops *ops = mdev_get_parent_ops(mdev);
+
+	ops->set_config(mdev, offset, buf, len);
+}
+
+static u32 virtio_mdev_generation(struct virtio_device *vdev)
+{
+	struct mdev_device *mdev = vm_get_mdev(vdev);
+	const struct virtio_mdev_parent_ops *ops = mdev_get_parent_ops(mdev);
+
+	return ops->get_generation(mdev);
+}
+
+static u8 virtio_mdev_get_status(struct virtio_device *vdev)
+{
+	struct mdev_device *mdev = vm_get_mdev(vdev);
+	const struct virtio_mdev_parent_ops *ops = mdev_get_parent_ops(mdev);
+
+	return ops->get_status(mdev);
+}
+
+static void virtio_mdev_set_status(struct virtio_device *vdev, u8 status)
+{
+	struct mdev_device *mdev = vm_get_mdev(vdev);
+	const struct virtio_mdev_parent_ops *ops = mdev_get_parent_ops(mdev);
+
+	return ops->set_status(mdev, status);
+}
+
+static void virtio_mdev_reset(struct virtio_device *vdev)
+{
+	struct mdev_device *mdev = vm_get_mdev(vdev);
+	const struct virtio_mdev_parent_ops *ops = mdev_get_parent_ops(mdev);
+
+	return ops->set_status(mdev, 0);
+}
+
+static bool virtio_mdev_notify(struct virtqueue *vq)
+{
+	struct mdev_device *mdev = vm_get_mdev(vq->vdev);
+	const struct virtio_mdev_parent_ops *ops = mdev_get_parent_ops(mdev);
+
+	ops->kick_vq(mdev, vq->index);
+
+	return true;
+}
+
+static irqreturn_t virtio_mdev_config_cb(void *private)
+{
+	struct virtio_mdev_device *vm_dev = private;
+
+	virtio_config_changed(&vm_dev->vdev);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t virtio_mdev_virtqueue_cb(void *private)
+{
+	struct virtio_mdev_vq_info *info = private;
+
+	return vring_interrupt(0, info->vq);
+}
+
+static struct virtqueue *
+virtio_mdev_setup_vq(struct virtio_device *vdev, unsigned index,
+		     void (*callback)(struct virtqueue *vq),
+		     const char *name, bool ctx)
+{
+	struct mdev_device *mdev = vm_get_mdev(vdev);
+	const struct virtio_mdev_parent_ops *ops = mdev_get_parent_ops(mdev);
+	struct virtio_mdev_vq_info *info;
+	struct virtio_mdev_callback cb;
+	struct virtqueue *vq;
+	u32 align, num;
+	u64 desc_addr, driver_addr, device_addr;
+	int err;
+
+	if (!name)
+		return NULL;
+
+	/* Queue shouldn't already be set up. */
+	if (ops->get_vq_ready(mdev, index)) {
+		err = -ENOENT;
+		goto error_available;
+	}
+
+	/* Allocate and fill out our active queue description */
+	info = kmalloc(sizeof(*info), GFP_KERNEL);
+	if (!info) {
+		err = -ENOMEM;
+		goto error_kmalloc;
+	}
+
+	num = ops->get_queue_max(mdev);
+	if (num == 0) {
+		err = -ENOENT;
+		goto error_new_virtqueue;
+	}
+
+	/* Create the vring */
+	align = ops->get_vq_align(mdev);
+	vq = vring_create_virtqueue(index, num, align, vdev,
+				    true, true, ctx,
+				    virtio_mdev_notify, callback, name);
+	if (!vq) {
+		err = -ENOMEM;
+		goto error_new_virtqueue;
+	}
+
+	/* Setup virtqueue callback */
+	cb.callback = virtio_mdev_virtqueue_cb;
+	cb.private = info;
+	ops->set_vq_cb(mdev, index, &cb);
+	ops->set_vq_num(mdev, index, virtqueue_get_vring_size(vq));
+
+	desc_addr = virtqueue_get_desc_addr(vq);
+	driver_addr = virtqueue_get_avail_addr(vq);
+	device_addr = virtqueue_get_used_addr(vq);
+
+	if (ops->set_vq_address(mdev, index,
+				desc_addr, driver_addr,
+				device_addr)) {
+		err = -EINVAL;
+		goto err_vq;
+	}
+
+	ops->set_vq_ready(mdev, index, 1);
+
+	vq->priv = info;
+	info->vq = vq;
+
+	return vq;
+
+err_vq:
+	vring_del_virtqueue(vq);
+error_new_virtqueue:
+	ops->set_vq_ready(mdev, index, 0);
+	WARN_ON(ops->get_vq_ready(mdev, index));
+	kfree(info);
+error_kmalloc:
+error_available:
+	return ERR_PTR(err);
+
+}
+
+static void virtio_mdev_del_vq(struct virtqueue *vq)
+{
+	struct mdev_device *mdev = vm_get_mdev(vq->vdev);
+	const struct virtio_mdev_parent_ops *ops = mdev_get_parent_ops(mdev);
+	struct virtio_mdev_vq_info *info = vq->priv;
+	unsigned int index = vq->index;
+
+	/* Select and deactivate the queue */
+	ops->set_vq_ready(mdev, index, 0);
+	WARN_ON(ops->get_vq_ready(mdev, index));
+
+	vring_del_virtqueue(vq);
+
+	kfree(info);
+}
+
+static void virtio_mdev_del_vqs(struct virtio_device *vdev)
+{
+	struct virtqueue *vq, *n;
+
+	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
+		virtio_mdev_del_vq(vq);
+}
+
+static int virtio_mdev_find_vqs(struct virtio_device *vdev, unsigned nvqs,
+				struct virtqueue *vqs[],
+				vq_callback_t *callbacks[],
+				const char * const names[],
+				const bool *ctx,
+				struct irq_affinity *desc)
+{
+	struct virtio_mdev_device *vm_dev = to_virtio_mdev_device(vdev);
+	struct mdev_device *mdev = vm_get_mdev(vdev);
+	const struct virtio_mdev_parent_ops *ops = mdev_get_parent_ops(mdev);
+	struct virtio_mdev_callback cb;
+	int i, err, queue_idx = 0;
+
+	vm_dev->vqs = kmalloc_array(queue_idx, sizeof(*vm_dev->vqs),
+				    GFP_KERNEL);
+	if (!vm_dev->vqs)
+		return -ENOMEM;
+
+	for (i = 0; i < nvqs; ++i) {
+		if (!names[i]) {
+			vqs[i] = NULL;
+			continue;
+		}
+
+		vqs[i] = virtio_mdev_setup_vq(vdev, queue_idx++,
+					      callbacks[i], names[i], ctx ?
+					      ctx[i] : false);
+		if (IS_ERR(vqs[i])) {
+			err = PTR_ERR(vqs[i]);
+			goto err_setup_vq;
+		}
+	}
+
+	cb.callback = virtio_mdev_config_cb;
+	cb.private = vm_dev;
+	ops->set_config_cb(mdev, &cb);
+
+	return 0;
+
+err_setup_vq:
+	kfree(vm_dev->vqs);
+	virtio_mdev_del_vqs(vdev);
+	return err;
+}
+
+static u64 virtio_mdev_get_features(struct virtio_device *vdev)
+{
+	struct mdev_device *mdev = vm_get_mdev(vdev);
+	const struct virtio_mdev_parent_ops *ops = mdev_get_parent_ops(mdev);
+
+	return ops->get_features(mdev);
+}
+
+static int virtio_mdev_finalize_features(struct virtio_device *vdev)
+{
+	struct mdev_device *mdev = vm_get_mdev(vdev);
+	const struct virtio_mdev_parent_ops *ops = mdev_get_parent_ops(mdev);
+
+	/* Give virtio_ring a chance to accept features. */
+	vring_transport_features(vdev);
+
+	return ops->set_features(mdev, vdev->features);
+}
+
+static const char *virtio_mdev_bus_name(struct virtio_device *vdev)
+{
+	struct virtio_mdev_device *vm_dev = to_virtio_mdev_device(vdev);
+	struct mdev_device *mdev = vm_dev->mdev;
+
+	return dev_name(&mdev->dev);
+}
+
+static const struct virtio_config_ops virtio_mdev_config_ops = {
+	.get		= virtio_mdev_get,
+	.set		= virtio_mdev_set,
+	.generation	= virtio_mdev_generation,
+	.get_status	= virtio_mdev_get_status,
+	.set_status	= virtio_mdev_set_status,
+	.reset		= virtio_mdev_reset,
+	.find_vqs	= virtio_mdev_find_vqs,
+	.del_vqs	= virtio_mdev_del_vqs,
+	.get_features	= virtio_mdev_get_features,
+	.finalize_features = virtio_mdev_finalize_features,
+	.bus_name	= virtio_mdev_bus_name,
+};
+
+static void virtio_mdev_release_dev(struct device *_d)
+{
+	struct virtio_device *vdev =
+	       container_of(_d, struct virtio_device, dev);
+	struct virtio_mdev_device *vm_dev =
+	       container_of(vdev, struct virtio_mdev_device, vdev);
+
+	devm_kfree(_d, vm_dev);
+}
+
+static int virtio_mdev_probe(struct device *dev)
+{
+	struct mdev_device *mdev = to_mdev_device(dev);
+	const struct virtio_mdev_parent_ops *ops = mdev_get_parent_ops(mdev);
+	struct virtio_mdev_device *vm_dev;
+	int rc;
+
+	vm_dev = devm_kzalloc(dev, sizeof(*vm_dev), GFP_KERNEL);
+	if (!vm_dev)
+		return -ENOMEM;
+
+	vm_dev->vdev.dev.parent = dev;
+	vm_dev->vdev.dev.release = virtio_mdev_release_dev;
+	vm_dev->vdev.config = &virtio_mdev_config_ops;
+	vm_dev->mdev = mdev;
+	vm_dev->vqs = NULL;
+	spin_lock_init(&vm_dev->lock);
+
+	vm_dev->version = ops->get_version(mdev);
+	if (vm_dev->version != 1) {
+		dev_err(dev, "Version %ld not supported!\n",
+			vm_dev->version);
+		return -ENXIO;
+	}
+
+	vm_dev->vdev.id.device = ops->get_device_id(mdev);
+	if (vm_dev->vdev.id.device == 0)
+		return -ENODEV;
+
+	vm_dev->vdev.id.vendor = ops->get_vendor_id(mdev);
+	rc = register_virtio_device(&vm_dev->vdev);
+	if (rc)
+		put_device(dev);
+
+	dev_set_drvdata(dev, vm_dev);
+
+	return rc;
+
+}
+
+static void virtio_mdev_remove(struct device *dev)
+{
+	struct virtio_mdev_device *vm_dev = dev_get_drvdata(dev);
+
+	unregister_virtio_device(&vm_dev->vdev);
+}
+
+static struct mdev_class_id id_table[] = {
+	{ MDEV_ID_VIRTIO },
+	{ 0 },
+};
+
+static struct mdev_driver virtio_mdev_driver = {
+	.name	= "virtio_mdev",
+	.probe	= virtio_mdev_probe,
+	.remove	= virtio_mdev_remove,
+	.id_table = id_table,
+};
+
+static int __init virtio_mdev_init(void)
+{
+	return mdev_register_driver(&virtio_mdev_driver, THIS_MODULE);
+}
+
+static void __exit virtio_mdev_exit(void)
+{
+	mdev_unregister_driver(&virtio_mdev_driver);
+}
+
+module_init(virtio_mdev_init)
+module_exit(virtio_mdev_exit)
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
-- 
2.19.1

[PATCH 5/6] vringh: fix copy direction of vringh_iov_push_kern()

[Jason Wang]

We want to copy from iov to buf, so the direction was wrong.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/vringh.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
index 08ad0d1f0476..a0a2d74967ef 100644
--- a/drivers/vhost/vringh.c
+++ b/drivers/vhost/vringh.c
@@ -852,6 +852,12 @@ static inline int xfer_kern(void *src, void *dst, size_t len)
 	return 0;
 }
 
+static inline int kern_xfer(void *dst, void *src, size_t len)
+{
+	memcpy(dst, src, len);
+	return 0;
+}
+
 /**
  * vringh_init_kern - initialize a vringh for a kernelspace vring.
  * @vrh: the vringh to initialize.
@@ -958,7 +964,7 @@ EXPORT_SYMBOL(vringh_iov_pull_kern);
 ssize_t vringh_iov_push_kern(struct vringh_kiov *wiov,
 			     const void *src, size_t len)
 {
-	return vringh_iov_xfer(wiov, (void *)src, len, xfer_kern);
+	return vringh_iov_xfer(wiov, (void *)src, len, kern_xfer);
 }
 EXPORT_SYMBOL(vringh_iov_push_kern);
 
-- 
2.19.1

[PATCH 6/6] docs: sample driver to demonstrate how to implement virtio-mdev framework

[Jason Wang]

This sample driver creates mdev device that simulate virtio net device
over virtio mdev transport. The device is implemented through vringh
and workqueue. A device specific dma ops is to make sure HVA is used
directly as the IOVA. This should be sufficient for kernel virtio
driver to work.

Only 'virtio' type is supported right now. I plan to add 'vhost' type
on top which requires some virtual IOMMU in this sample driver.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 MAINTAINERS                |   1 +
 samples/Kconfig            |   7 +
 samples/vfio-mdev/Makefile |   1 +
 samples/vfio-mdev/mvnet.c  | 688 +++++++++++++++++++++++++++++++++++++
 4 files changed, 697 insertions(+)
 create mode 100644 samples/vfio-mdev/mvnet.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 820ec250cc52..6cee388eec6a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17203,6 +17203,7 @@ F:	include/uapi/linux/virtio_*.h
 F:	drivers/crypto/virtio/
 F:	mm/balloon_compaction.c
 F:	drivers/vfio/mdev/virtio_mdev.c
+F:	samples/vfio-mdev/mvnet.c
 
 VIRTIO BLOCK AND SCSI DRIVERS
 M:	"Michael S. Tsirkin" <mst@redhat.com>
diff --git a/samples/Kconfig b/samples/Kconfig
index c8dacb4dda80..a1a1ca2c00b7 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -131,6 +131,13 @@ config SAMPLE_VFIO_MDEV_MDPY
 	  mediated device.  It is a simple framebuffer and supports
 	  the region display interface (VFIO_GFX_PLANE_TYPE_REGION).
 
+config SAMPLE_VIRTIO_MDEV_NET
+        tristate "Build virtio mdev net example mediated device sample code -- loadable modules only"
+	depends on VIRTIO_MDEV_DEVICE && VHOST_RING && m
+	help
+	  Build a networking sample device for use as a virtio
+	  mediated device.
+
 config SAMPLE_VFIO_MDEV_MDPY_FB
 	tristate "Build VFIO mdpy example guest fbdev driver -- loadable module only"
 	depends on FB && m
diff --git a/samples/vfio-mdev/Makefile b/samples/vfio-mdev/Makefile
index 10d179c4fdeb..f34af90ed0a0 100644
--- a/samples/vfio-mdev/Makefile
+++ b/samples/vfio-mdev/Makefile
@@ -3,3 +3,4 @@ obj-$(CONFIG_SAMPLE_VFIO_MDEV_MTTY) += mtty.o
 obj-$(CONFIG_SAMPLE_VFIO_MDEV_MDPY) += mdpy.o
 obj-$(CONFIG_SAMPLE_VFIO_MDEV_MDPY_FB) += mdpy-fb.o
 obj-$(CONFIG_SAMPLE_VFIO_MDEV_MBOCHS) += mbochs.o
+obj-$(CONFIG_SAMPLE_VIRTIO_MDEV_NET) += mvnet.o
diff --git a/samples/vfio-mdev/mvnet.c b/samples/vfio-mdev/mvnet.c
new file mode 100644
index 000000000000..591ba179bc7f
--- /dev/null
+++ b/samples/vfio-mdev/mvnet.c
@@ -0,0 +1,688 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Mediated virtual virtio-net device driver.
+ *
+ * Copyright (c) 2019, Red Hat Inc. All rights reserved.
+ *     Author: Jason Wang <jasowang@redhat.com>
+ *
+ * Sample driver that creates mdev device that simulates ethernet loopback
+ * device.
+ *
+ * Usage:
+ *
+ * # modprobe virtio_mdev
+ * # modprobe mvnet
+ * # cd /sys/devices/virtual/mvnet/mvnet/mdev_supported_types/mvnet-virtio
+ * # echo "83b8f4f2-509f-382f-3c1e-e6bfe0fa1001" > ./create
+ * # cd devices/83b8f4f2-509f-382f-3c1e-e6bfe0fa1001
+ * # ls -d virtio0
+ * virtio0
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/uuid.h>
+#include <linux/iommu.h>
+#include <linux/sysfs.h>
+#include <linux/file.h>
+#include <linux/etherdevice.h>
+#include <linux/mdev.h>
+#include <linux/vringh.h>
+#include <linux/virtio_mdev.h>
+#include <uapi/linux/virtio_config.h>
+#include <uapi/linux/virtio_net.h>
+
+#define VERSION_STRING  "0.1"
+#define DRIVER_AUTHOR   "Red Hat Corporation"
+
+#define MVNET_CLASS_NAME "mvnet"
+#define MVNET_NAME       "mvnet"
+
+/*
+ * Global Structures
+ */
+
+static struct mvnet_dev {
+	struct class	*vd_class;
+	struct idr	vd_idr;
+	struct device	dev;
+} mvnet_dev;
+
+struct mvnet_virtqueue {
+	struct vringh vring;
+	struct vringh_kiov iov;
+	unsigned short head;
+	bool ready;
+	u64 desc_addr;
+	u64 device_addr;
+	u64 driver_addr;
+	u32 num;
+	void *private;
+	irqreturn_t (*cb)(void *data);
+};
+
+#define MVNET_QUEUE_ALIGN PAGE_SIZE
+#define MVNET_QUEUE_MAX 256
+#define MVNET_DEVICE_ID 0x1
+#define MVNET_VENDOR_ID 0
+
+u64 mvnet_features = (1ULL << VIRTIO_F_ANY_LAYOUT) |
+		     (1ULL << VIRTIO_F_VERSION_1) |
+		     (1ULL << VIRTIO_F_IOMMU_PLATFORM);
+
+/* State of each mdev device */
+struct mvnet_state {
+	struct mvnet_virtqueue vqs[2];
+	struct work_struct work;
+	spinlock_t lock;
+	struct mdev_device *mdev;
+	struct virtio_net_config config;
+	void *buffer;
+	u32 status;
+	u32 generation;
+	u64 features;
+	struct list_head next;
+};
+
+static struct mutex mdev_list_lock;
+static struct list_head mdev_devices_list;
+
+static void mvnet_queue_ready(struct mvnet_state *mvnet, unsigned int idx)
+{
+	struct mvnet_virtqueue *vq = &mvnet->vqs[idx];
+	int ret;
+
+	ret = vringh_init_kern(&vq->vring, mvnet_features, MVNET_QUEUE_MAX,
+			       false, (struct vring_desc *)vq->desc_addr,
+			       (struct vring_avail *)vq->driver_addr,
+			       (struct vring_used *)vq->device_addr);
+}
+
+static void mvnet_vq_reset(struct mvnet_virtqueue *vq)
+{
+	vq->ready = 0;
+	vq->desc_addr = 0;
+	vq->driver_addr = 0;
+	vq->device_addr = 0;
+	vq->cb = NULL;
+	vq->private = NULL;
+	vringh_init_kern(&vq->vring, mvnet_features, MVNET_QUEUE_MAX,
+			false, 0, 0, 0);
+}
+
+static void mvnet_reset(struct mvnet_state *mvnet)
+{
+	int i;
+
+	for (i = 0; i < 2; i++)
+		mvnet_vq_reset(&mvnet->vqs[i]);
+
+	mvnet->features = 0;
+	mvnet->status = 0;
+	++mvnet->generation;
+}
+
+static void mvnet_work(struct work_struct *work)
+{
+	struct mvnet_state *mvnet = container_of(work, struct
+						 mvnet_state, work);
+	struct mvnet_virtqueue *txq = &mvnet->vqs[1];
+	struct mvnet_virtqueue *rxq = &mvnet->vqs[0];
+	size_t read, write, total_write;
+	int err;
+	int pkts = 0;
+
+	spin_lock(&mvnet->lock);
+
+	if (!txq->ready || !rxq->ready)
+		goto out;
+
+	while (true) {
+		total_write = 0;
+		err = vringh_getdesc_kern(&txq->vring, &txq->iov, NULL,
+					  &txq->head, GFP_ATOMIC);
+		if (err <= 0)
+			break;
+
+		err = vringh_getdesc_kern(&rxq->vring, NULL, &rxq->iov,
+					  &rxq->head, GFP_ATOMIC);
+		if (err <= 0) {
+			vringh_complete_kern(&txq->vring, txq->head, 0);
+			break;
+		}
+
+		while (true) {
+			read = vringh_iov_pull_kern(&txq->iov, mvnet->buffer,
+						    PAGE_SIZE);
+			if (read <= 0)
+				break;
+
+			write = vringh_iov_push_kern(&rxq->iov, mvnet->buffer,
+						     read);
+			if (write <= 0)
+				break;
+
+			total_write += write;
+		}
+
+		/* Make sure data is wrote before advancing index */
+		smp_wmb();
+
+		vringh_complete_kern(&txq->vring, txq->head, 0);
+		vringh_complete_kern(&rxq->vring, rxq->head, total_write);
+
+		/* Make sure used is visible before rasing the interrupt. */
+		smp_wmb();
+
+		local_bh_disable();
+		if (txq->cb)
+			txq->cb(txq->private);
+		if (rxq->cb)
+			rxq->cb(rxq->private);
+		local_bh_enable();
+
+		if (++pkts > 4) {
+			schedule_work(&mvnet->work);
+			goto out;
+		}
+	}
+
+out:
+	spin_unlock(&mvnet->lock);
+}
+
+static dma_addr_t mvnet_map_page(struct device *dev, struct page *page,
+				 unsigned long offset, size_t size,
+				 enum dma_data_direction dir,
+				 unsigned long attrs)
+{
+	/* Vringh can only use HVA */
+	return (dma_addr_t)(page_address(page) + offset);
+}
+
+static void mvnet_unmap_page(struct device *dev, dma_addr_t dma_addr,
+			     size_t size, enum dma_data_direction dir,
+			     unsigned long attrs)
+{
+}
+
+static void *mvnet_alloc_coherent(struct device *dev, size_t size,
+				  dma_addr_t *dma_addr, gfp_t flag,
+				  unsigned long attrs)
+{
+	void *addr = kmalloc(size, flag);
+
+	if (addr == NULL)
+		*dma_addr = DMA_MAPPING_ERROR;
+	else
+		*dma_addr = (dma_addr_t) addr;
+
+	return addr;
+}
+
+static void mvnet_free_coherent(struct device *dev, size_t size,
+				void *vaddr, dma_addr_t dma_addr,
+				unsigned long attrs)
+{
+	kfree((void *)dma_addr);
+}
+
+static const struct dma_map_ops mvnet_dma_ops = {
+	.map_page = mvnet_map_page,
+	.unmap_page = mvnet_unmap_page,
+	.alloc = mvnet_alloc_coherent,
+	.free = mvnet_free_coherent,
+};
+
+static int mvnet_create(struct kobject *kobj, struct mdev_device *mdev)
+{
+	struct mvnet_state *mvnet;
+	struct virtio_net_config *config;
+	struct device *dev = mdev_dev(mdev);
+
+	if (!mdev)
+		return -EINVAL;
+
+	mvnet = kzalloc(sizeof(struct mvnet_state), GFP_KERNEL);
+	if (mvnet == NULL)
+		return -ENOMEM;
+
+	mvnet->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!mvnet->buffer) {
+		kfree(mvnet);
+		return -ENOMEM;
+	}
+
+	config = &mvnet->config;
+	config->mtu = 1500;
+	config->status = VIRTIO_NET_S_LINK_UP;
+	eth_random_addr(config->mac);
+
+	INIT_WORK(&mvnet->work, mvnet_work);
+
+	spin_lock_init(&mvnet->lock);
+	mvnet->mdev = mdev;
+	mdev_set_drvdata(mdev, mvnet);
+
+	mutex_lock(&mdev_list_lock);
+	list_add(&mvnet->next, &mdev_devices_list);
+	mutex_unlock(&mdev_list_lock);
+
+	dev->coherent_dma_mask = DMA_BIT_MASK(64);
+	set_dma_ops(dev, &mvnet_dma_ops);
+
+	return 0;
+}
+
+static int mvnet_remove(struct mdev_device *mdev)
+{
+	struct mvnet_state *mds, *tmp_mds;
+	struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+	int ret = -EINVAL;
+
+	mutex_lock(&mdev_list_lock);
+	list_for_each_entry_safe(mds, tmp_mds, &mdev_devices_list, next) {
+		if (mvnet == mds) {
+			list_del(&mvnet->next);
+			mdev_set_drvdata(mdev, NULL);
+			kfree(mvnet->buffer);
+			kfree(mvnet);
+			ret = 0;
+			break;
+		}
+	}
+	mutex_unlock(&mdev_list_lock);
+
+	return ret;
+}
+
+static ssize_t
+sample_mvnet_dev_show(struct device *dev, struct device_attribute *attr,
+		     char *buf)
+{
+	if (mdev_from_dev(dev))
+		return sprintf(buf, "This is MDEV %s\n", dev_name(dev));
+
+	return sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR_RO(sample_mvnet_dev);
+
+static struct attribute *mvnet_dev_attrs[] = {
+	&dev_attr_sample_mvnet_dev.attr,
+	NULL,
+};
+
+static const struct attribute_group mvnet_dev_group = {
+	.name  = "mvnet_dev",
+	.attrs = mvnet_dev_attrs,
+};
+
+static const struct attribute_group *mvnet_dev_groups[] = {
+	&mvnet_dev_group,
+	NULL,
+};
+
+static ssize_t
+sample_mdev_dev_show(struct device *dev, struct device_attribute *attr,
+		     char *buf)
+{
+	if (mdev_from_dev(dev))
+		return sprintf(buf, "This is MDEV %s\n", dev_name(dev));
+
+	return sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR_RO(sample_mdev_dev);
+
+static struct attribute *mdev_dev_attrs[] = {
+	&dev_attr_sample_mdev_dev.attr,
+	NULL,
+};
+
+static const struct attribute_group mdev_dev_group = {
+	.name  = "vendor",
+	.attrs = mdev_dev_attrs,
+};
+
+static const struct attribute_group *mdev_dev_groups[] = {
+	&mdev_dev_group,
+	NULL,
+};
+
+#define MVNET_STRING_LEN 16
+
+static ssize_t
+name_show(struct kobject *kobj, struct device *dev, char *buf)
+{
+	char name[MVNET_STRING_LEN];
+	const char *name_str = "virtio-net";
+
+	snprintf(name, MVNET_STRING_LEN, "%s", dev_driver_string(dev));
+	if (!strcmp(kobj->name, name))
+		return sprintf(buf, "%s\n", name_str);
+
+	return -EINVAL;
+}
+
+static MDEV_TYPE_ATTR_RO(name);
+
+static ssize_t
+available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
+{
+	return sprintf(buf, "%d\n", INT_MAX);
+}
+
+static MDEV_TYPE_ATTR_RO(available_instances);
+
+static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
+			       char *buf)
+{
+	return sprintf(buf, "%s\n", VIRTIO_MDEV_DEVICE_API_STRING);
+}
+
+static MDEV_TYPE_ATTR_RO(device_api);
+
+static struct attribute *mdev_types_attrs[] = {
+	&mdev_type_attr_name.attr,
+	&mdev_type_attr_device_api.attr,
+	&mdev_type_attr_available_instances.attr,
+	NULL,
+};
+
+static struct attribute_group mdev_type_group = {
+	.name  = "virtio",
+	.attrs = mdev_types_attrs,
+};
+
+/* TBD: "vhost" type */
+
+static struct attribute_group *mdev_type_groups[] = {
+	&mdev_type_group,
+	NULL,
+};
+
+static int mvnet_set_vq_address(struct mdev_device *mdev, u16 idx,
+				u64 desc_area, u64 driver_area, u64 device_area)
+{
+	struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+	struct mvnet_virtqueue *vq = &mvnet->vqs[idx];
+
+	vq->desc_addr = desc_area;
+	vq->driver_addr = driver_area;
+	vq->device_addr = device_area;
+
+	return 0;
+}
+
+static void mvnet_set_vq_num(struct mdev_device *mdev, u16 idx, u32 num)
+{
+	struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+	struct mvnet_virtqueue *vq = &mvnet->vqs[idx];
+
+	vq->num = num;
+}
+
+static void mvnet_kick_vq(struct mdev_device *mdev, u16 idx)
+{
+	struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+	struct mvnet_virtqueue *vq = &mvnet->vqs[idx];
+
+	if (vq->ready)
+		schedule_work(&mvnet->work);
+}
+
+static void mvnet_set_vq_cb(struct mdev_device *mdev, u16 idx,
+			    struct virtio_mdev_callback *cb)
+{
+	struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+	struct mvnet_virtqueue *vq = &mvnet->vqs[idx];
+
+	vq->cb = cb->callback;
+	vq->private = cb->private;
+}
+
+static void mvnet_set_vq_ready(struct mdev_device *mdev, u16 idx, bool ready)
+{
+	struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+	struct mvnet_virtqueue *vq = &mvnet->vqs[idx];
+
+	spin_lock(&mvnet->lock);
+	vq->ready = ready;
+	if (vq->ready)
+		mvnet_queue_ready(mvnet, idx);
+	spin_unlock(&mvnet->lock);
+}
+
+static bool mvnet_get_vq_ready(struct mdev_device *mdev, u16 idx)
+{
+	struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+	struct mvnet_virtqueue *vq = &mvnet->vqs[idx];
+
+	return vq->ready;
+}
+
+static int mvnet_set_vq_state(struct mdev_device *mdev, u16 idx, u64 state)
+{
+	struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+	struct mvnet_virtqueue *vq = &mvnet->vqs[idx];
+	struct vringh *vrh = &vq->vring;
+
+	spin_lock(&mvnet->lock);
+	vrh->last_avail_idx = state;
+	spin_unlock(&mvnet->lock);
+
+	return 0;
+}
+
+static u64 mvnet_get_vq_state(struct mdev_device *mdev, u16 idx)
+{
+	struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+	struct mvnet_virtqueue *vq = &mvnet->vqs[idx];
+	struct vringh *vrh = &vq->vring;
+
+	return vrh->last_avail_idx;
+}
+
+static u16 mvnet_get_vq_align(struct mdev_device *mdev)
+{
+	return MVNET_QUEUE_ALIGN;
+}
+
+static u64 mvnet_get_features(struct mdev_device *mdev)
+{
+	return mvnet_features;
+}
+
+static int mvnet_set_features(struct mdev_device *mdev, u64 features)
+{
+	struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+
+	/* DMA mapping must be done by driver */
+	if (!(features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)))
+		return -EINVAL;
+
+	mvnet->features = features & mvnet_features;
+
+	return 0;
+}
+
+static void mvnet_set_config_cb(struct mdev_device *mdev,
+				struct virtio_mdev_callback *cb)
+{
+	/* We don't support config interrupt */
+}
+
+static u16 mvnet_get_queue_max(struct mdev_device *mdev)
+{
+	return MVNET_QUEUE_MAX;
+}
+
+static u32 mvnet_get_device_id(struct mdev_device *mdev)
+{
+	return MVNET_DEVICE_ID;
+}
+
+static u32 mvnet_get_vendor_id(struct mdev_device *mdev)
+{
+	return MVNET_VENDOR_ID;
+}
+
+static u8 mvnet_get_status(struct mdev_device *mdev)
+{
+	struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+
+	return mvnet->status;
+}
+
+static void mvnet_set_status(struct mdev_device *mdev, u8 status)
+{
+	struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+
+	mvnet->status = status;
+
+	if (status == 0) {
+		spin_lock(&mvnet->lock);
+		mvnet_reset(mvnet);
+		spin_unlock(&mvnet->lock);
+	}
+}
+
+static void mvnet_get_config(struct mdev_device *mdev, unsigned int offset,
+			     void *buf, unsigned int len)
+{
+	struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+
+	if (offset + len < sizeof(struct virtio_net_config))
+		memcpy(buf, &mvnet->config + offset, len);
+}
+
+static void mvnet_set_config(struct mdev_device *mdev, unsigned int offset,
+			     const void *buf, unsigned int len)
+{
+	/* No writable config supportted by mvnet */
+}
+
+static int mvnet_get_version(struct mdev_device *mdev)
+{
+	return 0x1;
+}
+
+static u32 mvnet_get_generation(struct mdev_device *mdev)
+{
+	struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+
+	return mvnet->generation;
+}
+
+static const struct virtio_mdev_parent_ops virtio_mdev_ops = {
+	.set_vq_address         = mvnet_set_vq_address,
+	.set_vq_num             = mvnet_set_vq_num,
+	.kick_vq                = mvnet_kick_vq,
+	.set_vq_cb              = mvnet_set_vq_cb,
+	.set_vq_ready           = mvnet_set_vq_ready,
+	.get_vq_ready           = mvnet_get_vq_ready,
+	.set_vq_state           = mvnet_set_vq_state,
+	.get_vq_state           = mvnet_get_vq_state,
+	.get_vq_align           = mvnet_get_vq_align,
+	.get_features           = mvnet_get_features,
+	.set_features           = mvnet_set_features,
+	.set_config_cb          = mvnet_set_config_cb,
+	.get_queue_max          = mvnet_get_queue_max,
+	.get_device_id          = mvnet_get_device_id,
+	.get_vendor_id          = mvnet_get_vendor_id,
+	.get_status             = mvnet_get_status,
+	.set_status             = mvnet_set_status,
+	.get_config             = mvnet_get_config,
+	.set_config             = mvnet_set_config,
+	.get_version            = mvnet_get_version,
+	.get_generation         = mvnet_get_generation,
+};
+
+static const struct mdev_parent_ops mdev_fops = {
+	.owner                  = THIS_MODULE,
+	.dev_attr_groups        = mvnet_dev_groups,
+	.mdev_attr_groups       = mdev_dev_groups,
+	.supported_type_groups  = mdev_type_groups,
+	.create                 = mvnet_create,
+	.remove			= mvnet_remove,
+	.device_ops		= &virtio_mdev_ops,
+};
+
+static void mvnet_device_release(struct device *dev)
+{
+	dev_dbg(dev, "mvnet: released\n");
+}
+
+static int __init mvnet_dev_init(void)
+{
+	int ret = 0;
+
+	pr_info("mvnet_dev: %s\n", __func__);
+
+	memset(&mvnet_dev, 0, sizeof(mvnet_dev));
+
+	idr_init(&mvnet_dev.vd_idr);
+
+	mvnet_dev.vd_class = class_create(THIS_MODULE, MVNET_CLASS_NAME);
+
+	if (IS_ERR(mvnet_dev.vd_class)) {
+		pr_err("Error: failed to register mvnet_dev class\n");
+		ret = PTR_ERR(mvnet_dev.vd_class);
+		goto failed1;
+	}
+
+	mvnet_dev.dev.class = mvnet_dev.vd_class;
+	mvnet_dev.dev.release = mvnet_device_release;
+	dev_set_name(&mvnet_dev.dev, "%s", MVNET_NAME);
+
+	ret = device_register(&mvnet_dev.dev);
+	if (ret)
+		goto failed2;
+
+	ret = mdev_register_virtio_device(&mvnet_dev.dev, &mdev_fops);
+	if (ret)
+		goto failed3;
+
+	mutex_init(&mdev_list_lock);
+	INIT_LIST_HEAD(&mdev_devices_list);
+
+	goto all_done;
+
+failed3:
+
+	device_unregister(&mvnet_dev.dev);
+failed2:
+	class_destroy(mvnet_dev.vd_class);
+
+failed1:
+all_done:
+	return ret;
+}
+
+static void __exit mvnet_dev_exit(void)
+{
+	mvnet_dev.dev.bus = NULL;
+	mdev_unregister_device(&mvnet_dev.dev);
+
+	device_unregister(&mvnet_dev.dev);
+	idr_destroy(&mvnet_dev.vd_idr);
+	class_destroy(mvnet_dev.vd_class);
+	mvnet_dev.vd_class = NULL;
+	pr_info("mvnet_dev: Unloaded!\n");
+}
+
+module_init(mvnet_dev_init)
+module_exit(mvnet_dev_exit)
+
+MODULE_LICENSE("GPL v2");
+MODULE_INFO(supported, "Simulate loopback ethernet device over mdev");
+MODULE_VERSION(VERSION_STRING);
+MODULE_AUTHOR(DRIVER_AUTHOR);
-- 
2.19.1

Re: [PATCH 0/6] mdev based hardware virtio offloading support

[Michael S. Tsirkin]

On Mon, Sep 23, 2019 at 09:03:25PM +0800, Jason Wang wrote:
> Hi all:
> 
> There are hardware that can do virtio datapath offloading while having
> its own control path. This path tries to implement a mdev based
> unified API to support using kernel virtio driver to drive those
> devices. This is done by introducing a new mdev transport for virtio
> (virtio_mdev) and register itself as a new kind of mdev driver. Then
> it provides a unified way for kernel virtio driver to talk with mdev
> device implementation.
> 
> Though the series only contains kernel driver support, the goal is to
> make the transport generic enough to support userspace drivers. This
> means vhost-mdev[1] could be built on top as well by resuing the
> transport.
> 
> A sample driver is also implemented which simulate a virito-net
> loopback ethernet device on top of vringh + workqueue. This could be
> used as a reference implementation for real hardware driver.
> 
> Consider mdev framework only support VFIO device and driver right now,
> this series also extend it to support other types. This is done
> through introducing class id to the device and pairing it with
> id_talbe claimed by the driver. On top, this seris also decouple
> device specific parents ops out of the common ones.
> 
> Pktgen test was done with virito-net + mvnet loop back device.
> 
> Please review.
> 
> [1] https://lkml.org/lkml/2019/9/16/869
> 
> Changes from RFC-V2:
> - silent compile warnings on some specific configuration
> - use u16 instead u8 for class id
> - reseve MDEV_ID_VHOST for future vhost-mdev work
> - introduce "virtio" type for mvnet and make "vhost" type for future
>   work
> - add entries in MAINTAINER
> - tweak and typos fixes in commit log
> 
> Changes from RFC-V1:
> 
> - rename device id to class id
> - add docs for class id and device specific ops (device_ops)
> - split device_ops into seperate headers
> - drop the mdev_set_dma_ops()
> - use device_ops to implement the transport API, then it's not a part
>   of UAPI any more
> - use GFP_ATOMIC in mvnet sample device and other tweaks
> - set_vring_base/get_vring_base support for mvnet device
> 
> Jason Wang (6):
>   mdev: class id support
>   mdev: introduce device specific ops
>   mdev: introduce virtio device and its device ops
>   virtio: introduce a mdev based transport
>   vringh: fix copy direction of vringh_iov_push_kern()
>   docs: sample driver to demonstrate how to implement virtio-mdev
>     framework


That's pretty clean, so how about we start by just merging this?
Alex are you going to handle this through your next tree?
If yes, pls include:

Acked-by: Michael S. Tsirkin <mst@redhat.com>



>  .../driver-api/vfio-mediated-device.rst       |  11 +-
>  MAINTAINERS                                   |   3 +
>  drivers/gpu/drm/i915/gvt/kvmgt.c              |  17 +-
>  drivers/s390/cio/vfio_ccw_ops.c               |  17 +-
>  drivers/s390/crypto/vfio_ap_ops.c             |  14 +-
>  drivers/vfio/mdev/Kconfig                     |   7 +
>  drivers/vfio/mdev/Makefile                    |   1 +
>  drivers/vfio/mdev/mdev_core.c                 |  21 +-
>  drivers/vfio/mdev/mdev_driver.c               |  14 +
>  drivers/vfio/mdev/mdev_private.h              |   1 +
>  drivers/vfio/mdev/vfio_mdev.c                 |  37 +-
>  drivers/vfio/mdev/virtio_mdev.c               | 416 +++++++++++
>  drivers/vhost/vringh.c                        |   8 +-
>  include/linux/mdev.h                          |  47 +-
>  include/linux/mod_devicetable.h               |   8 +
>  include/linux/vfio_mdev.h                     |  53 ++
>  include/linux/virtio_mdev.h                   | 144 ++++
>  samples/Kconfig                               |   7 +
>  samples/vfio-mdev/Makefile                    |   1 +
>  samples/vfio-mdev/mbochs.c                    |  19 +-
>  samples/vfio-mdev/mdpy.c                      |  19 +-
>  samples/vfio-mdev/mtty.c                      |  17 +-
>  samples/vfio-mdev/mvnet.c                     | 688 ++++++++++++++++++
>  23 files changed, 1481 insertions(+), 89 deletions(-)
>  create mode 100644 drivers/vfio/mdev/virtio_mdev.c
>  create mode 100644 include/linux/vfio_mdev.h
>  create mode 100644 include/linux/virtio_mdev.h
>  create mode 100644 samples/vfio-mdev/mvnet.c
> 
> -- 
> 2.19.1

Re: [PATCH 2/6] mdev: introduce device specific ops

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 11306 bytes --]

Hi Jason,

I love your patch! Yet something to improve:

[auto build test ERROR on linus/master]
[cannot apply to v5.3 next-20190920]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Jason-Wang/mdev-based-hardware-virtio-offloading-support/20190923-210738
config: ia64-allmodconfig (attached as .config)
compiler: ia64-linux-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=ia64 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All error/warnings (new ones prefixed by >>):

   In file included from include/linux/vfio_mdev.h:10:0,
                    from <command-line>:0:
>> include/linux/mdev.h:25:34: warning: 'struct device' declared inside parameter list will not be visible outside of this definition or declaration
    int mdev_set_iommu_device(struct device *dev, struct device *iommu_device);
                                     ^~~~~~
>> include/linux/mdev.h:62:27: warning: 'struct kobject' declared inside parameter list will not be visible outside of this definition or declaration
     int     (*create)(struct kobject *kobj, struct mdev_device *mdev);
                              ^~~~~~~
>> include/linux/mdev.h:69:19: error: field 'attr' has incomplete type
     struct attribute attr;
                      ^~~~
   include/linux/mdev.h:70:25: warning: 'struct kobject' declared inside parameter list will not be visible outside of this definition or declaration
     ssize_t (*show)(struct kobject *kobj, struct device *dev, char *buf);
                            ^~~~~~~
   include/linux/mdev.h:71:26: warning: 'struct kobject' declared inside parameter list will not be visible outside of this definition or declaration
     ssize_t (*store)(struct kobject *kobj, struct device *dev,
                             ^~~~~~~
>> include/linux/mdev.h:98:23: error: field 'driver' has incomplete type
     struct device_driver driver;
                          ^~~~~~
>> include/linux/mdev.h:106:7: error: unknown type name 'guid_t'
    const guid_t *mdev_uuid(struct mdev_device *mdev);
          ^~~~~~
   In file included from <command-line>:0:0:
>> include/linux/vfio_mdev.h:50:47: warning: 'struct vm_area_struct' declared inside parameter list will not be visible outside of this definition or declaration
     int (*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
                                                  ^~~~~~~~~~~~~~

vim +/attr +69 include/linux/mdev.h

7b96953bc640b6 Kirti Wankhede  2016-11-17   14  
8ac13175cbe985 Lu Baolu        2019-04-12   15  /*
8ac13175cbe985 Lu Baolu        2019-04-12   16   * Called by the parent device driver to set the device which represents
8ac13175cbe985 Lu Baolu        2019-04-12   17   * this mdev in iommu protection scope. By default, the iommu device is
8ac13175cbe985 Lu Baolu        2019-04-12   18   * NULL, that indicates using vendor defined isolation.
8ac13175cbe985 Lu Baolu        2019-04-12   19   *
8ac13175cbe985 Lu Baolu        2019-04-12   20   * @dev: the mediated device that iommu will isolate.
8ac13175cbe985 Lu Baolu        2019-04-12   21   * @iommu_device: a pci device which represents the iommu for @dev.
8ac13175cbe985 Lu Baolu        2019-04-12   22   *
8ac13175cbe985 Lu Baolu        2019-04-12   23   * Return 0 for success, otherwise negative error value.
8ac13175cbe985 Lu Baolu        2019-04-12   24   */
8ac13175cbe985 Lu Baolu        2019-04-12  @25  int mdev_set_iommu_device(struct device *dev, struct device *iommu_device);
8ac13175cbe985 Lu Baolu        2019-04-12   26  
8ac13175cbe985 Lu Baolu        2019-04-12   27  struct device *mdev_get_iommu_device(struct device *dev);
8ac13175cbe985 Lu Baolu        2019-04-12   28  
7b96953bc640b6 Kirti Wankhede  2016-11-17   29  /**
42930553a7c11f Alex Williamson 2016-12-30   30   * struct mdev_parent_ops - Structure to be registered for each parent device to
7b96953bc640b6 Kirti Wankhede  2016-11-17   31   * register the device to mdev module.
7b96953bc640b6 Kirti Wankhede  2016-11-17   32   *
7b96953bc640b6 Kirti Wankhede  2016-11-17   33   * @owner:		The module owner.
7b96953bc640b6 Kirti Wankhede  2016-11-17   34   * @dev_attr_groups:	Attributes of the parent device.
7b96953bc640b6 Kirti Wankhede  2016-11-17   35   * @mdev_attr_groups:	Attributes of the mediated device.
7b96953bc640b6 Kirti Wankhede  2016-11-17   36   * @supported_type_groups: Attributes to define supported types. It is mandatory
7b96953bc640b6 Kirti Wankhede  2016-11-17   37   *			to provide supported types.
7b96953bc640b6 Kirti Wankhede  2016-11-17   38   * @create:		Called to allocate basic resources in parent device's
7b96953bc640b6 Kirti Wankhede  2016-11-17   39   *			driver for a particular mediated device. It is
7b96953bc640b6 Kirti Wankhede  2016-11-17   40   *			mandatory to provide create ops.
7b96953bc640b6 Kirti Wankhede  2016-11-17   41   *			@kobj: kobject of type for which 'create' is called.
7b96953bc640b6 Kirti Wankhede  2016-11-17   42   *			@mdev: mdev_device structure on of mediated device
7b96953bc640b6 Kirti Wankhede  2016-11-17   43   *			      that is being created
7b96953bc640b6 Kirti Wankhede  2016-11-17   44   *			Returns integer: success (0) or error (< 0)
7b96953bc640b6 Kirti Wankhede  2016-11-17   45   * @remove:		Called to free resources in parent device's driver for a
7b96953bc640b6 Kirti Wankhede  2016-11-17   46   *			a mediated device. It is mandatory to provide 'remove'
7b96953bc640b6 Kirti Wankhede  2016-11-17   47   *			ops.
7b96953bc640b6 Kirti Wankhede  2016-11-17   48   *			@mdev: mdev_device device structure which is being
7b96953bc640b6 Kirti Wankhede  2016-11-17   49   *			       destroyed
7b96953bc640b6 Kirti Wankhede  2016-11-17   50   *			Returns integer: success (0) or error (< 0)
0baad8a6f6fefa Jason Wang      2019-09-23   51   * @device_ops:         Device specific emulation callback.
0baad8a6f6fefa Jason Wang      2019-09-23   52   *
7b96953bc640b6 Kirti Wankhede  2016-11-17   53   * Parent device that support mediated device should be registered with mdev
42930553a7c11f Alex Williamson 2016-12-30   54   * module with mdev_parent_ops structure.
7b96953bc640b6 Kirti Wankhede  2016-11-17   55   **/
42930553a7c11f Alex Williamson 2016-12-30   56  struct mdev_parent_ops {
7b96953bc640b6 Kirti Wankhede  2016-11-17   57  	struct module   *owner;
7b96953bc640b6 Kirti Wankhede  2016-11-17   58  	const struct attribute_group **dev_attr_groups;
7b96953bc640b6 Kirti Wankhede  2016-11-17   59  	const struct attribute_group **mdev_attr_groups;
7b96953bc640b6 Kirti Wankhede  2016-11-17   60  	struct attribute_group **supported_type_groups;
7b96953bc640b6 Kirti Wankhede  2016-11-17   61  
7b96953bc640b6 Kirti Wankhede  2016-11-17  @62  	int     (*create)(struct kobject *kobj, struct mdev_device *mdev);
7b96953bc640b6 Kirti Wankhede  2016-11-17   63  	int     (*remove)(struct mdev_device *mdev);
0baad8a6f6fefa Jason Wang      2019-09-23   64  	const void *device_ops;
7b96953bc640b6 Kirti Wankhede  2016-11-17   65  };
7b96953bc640b6 Kirti Wankhede  2016-11-17   66  
7b96953bc640b6 Kirti Wankhede  2016-11-17   67  /* interface for exporting mdev supported type attributes */
7b96953bc640b6 Kirti Wankhede  2016-11-17   68  struct mdev_type_attribute {
7b96953bc640b6 Kirti Wankhede  2016-11-17  @69  	struct attribute attr;
7b96953bc640b6 Kirti Wankhede  2016-11-17  @70  	ssize_t (*show)(struct kobject *kobj, struct device *dev, char *buf);
7b96953bc640b6 Kirti Wankhede  2016-11-17   71  	ssize_t (*store)(struct kobject *kobj, struct device *dev,
7b96953bc640b6 Kirti Wankhede  2016-11-17   72  			 const char *buf, size_t count);
7b96953bc640b6 Kirti Wankhede  2016-11-17   73  };
7b96953bc640b6 Kirti Wankhede  2016-11-17   74  
7b96953bc640b6 Kirti Wankhede  2016-11-17   75  #define MDEV_TYPE_ATTR(_name, _mode, _show, _store)		\
7b96953bc640b6 Kirti Wankhede  2016-11-17   76  struct mdev_type_attribute mdev_type_attr_##_name =		\
7b96953bc640b6 Kirti Wankhede  2016-11-17   77  	__ATTR(_name, _mode, _show, _store)
7b96953bc640b6 Kirti Wankhede  2016-11-17   78  #define MDEV_TYPE_ATTR_RW(_name) \
7b96953bc640b6 Kirti Wankhede  2016-11-17   79  	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RW(_name)
7b96953bc640b6 Kirti Wankhede  2016-11-17   80  #define MDEV_TYPE_ATTR_RO(_name) \
7b96953bc640b6 Kirti Wankhede  2016-11-17   81  	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RO(_name)
7b96953bc640b6 Kirti Wankhede  2016-11-17   82  #define MDEV_TYPE_ATTR_WO(_name) \
7b96953bc640b6 Kirti Wankhede  2016-11-17   83  	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_WO(_name)
7b96953bc640b6 Kirti Wankhede  2016-11-17   84  
7b96953bc640b6 Kirti Wankhede  2016-11-17   85  /**
7b96953bc640b6 Kirti Wankhede  2016-11-17   86   * struct mdev_driver - Mediated device driver
7b96953bc640b6 Kirti Wankhede  2016-11-17   87   * @name: driver name
7b96953bc640b6 Kirti Wankhede  2016-11-17   88   * @probe: called when new device created
7b96953bc640b6 Kirti Wankhede  2016-11-17   89   * @remove: called when device removed
7b96953bc640b6 Kirti Wankhede  2016-11-17   90   * @driver: device driver structure
6294ee8e0b5153 Jason Wang      2019-09-23   91   * @id_table: the ids serviced by this driver.
7b96953bc640b6 Kirti Wankhede  2016-11-17   92   *
7b96953bc640b6 Kirti Wankhede  2016-11-17   93   **/
7b96953bc640b6 Kirti Wankhede  2016-11-17   94  struct mdev_driver {
7b96953bc640b6 Kirti Wankhede  2016-11-17   95  	const char *name;
7b96953bc640b6 Kirti Wankhede  2016-11-17   96  	int  (*probe)(struct device *dev);
7b96953bc640b6 Kirti Wankhede  2016-11-17   97  	void (*remove)(struct device *dev);
7b96953bc640b6 Kirti Wankhede  2016-11-17  @98  	struct device_driver driver;
6294ee8e0b5153 Jason Wang      2019-09-23   99  	const struct mdev_class_id *id_table;
7b96953bc640b6 Kirti Wankhede  2016-11-17  100  };
7b96953bc640b6 Kirti Wankhede  2016-11-17  101  
7b96953bc640b6 Kirti Wankhede  2016-11-17  102  #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
7b96953bc640b6 Kirti Wankhede  2016-11-17  103  
50732af3b65691 Parav Pandit    2019-04-30  104  void *mdev_get_drvdata(struct mdev_device *mdev);
50732af3b65691 Parav Pandit    2019-04-30  105  void mdev_set_drvdata(struct mdev_device *mdev, void *data);
50732af3b65691 Parav Pandit    2019-04-30 @106  const guid_t *mdev_uuid(struct mdev_device *mdev);
7b96953bc640b6 Kirti Wankhede  2016-11-17  107  

:::::: The code at line 69 was first introduced by commit
:::::: 7b96953bc640b6b25665fe17ffca4b668b371f14 vfio: Mediated device Core driver

:::::: TO: Kirti Wankhede <kwankhede@nvidia.com>
:::::: CC: Alex Williamson <alex.williamson@redhat.com>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 54846 bytes --]

Re: [PATCH 2/6] mdev: introduce device specific ops

[Michael S. Tsirkin]

On Mon, Sep 23, 2019 at 11:20:12PM +0800, kbuild test robot wrote:
> Hi Jason,
> 
> I love your patch! Yet something to improve:
> 
> [auto build test ERROR on linus/master]
> [cannot apply to v5.3 next-20190920]
> [if your patch is applied to the wrong git tree, please drop us a note to help
> improve the system. BTW, we also suggest to use '--base' option to specify the
> base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
> 
> url:    https://github.com/0day-ci/linux/commits/Jason-Wang/mdev-based-hardware-virtio-offloading-support/20190923-210738
> config: ia64-allmodconfig (attached as .config)
> compiler: ia64-linux-gcc (GCC) 7.4.0
> reproduce:
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # save the attached .config to linux build tree
>         GCC_VERSION=7.4.0 make.cross ARCH=ia64 
> 
> If you fix the issue, kindly add following tag
> Reported-by: kbuild test robot <lkp@intel.com>
> 
> All error/warnings (new ones prefixed by >>):

Looks like a bunch of includes missing. I guess they happen to
be pulled in on some platforms but not others - ideally
headers should be self contained though, pulling in
all their dependencies.


>    In file included from include/linux/vfio_mdev.h:10:0,
>                     from <command-line>:0:
> >> include/linux/mdev.h:25:34: warning: 'struct device' declared inside parameter list will not be visible outside of this definition or declaration
>     int mdev_set_iommu_device(struct device *dev, struct device *iommu_device);
>                                      ^~~~~~
> >> include/linux/mdev.h:62:27: warning: 'struct kobject' declared inside parameter list will not be visible outside of this definition or declaration
>      int     (*create)(struct kobject *kobj, struct mdev_device *mdev);
>                               ^~~~~~~
> >> include/linux/mdev.h:69:19: error: field 'attr' has incomplete type
>      struct attribute attr;
>                       ^~~~
>    include/linux/mdev.h:70:25: warning: 'struct kobject' declared inside parameter list will not be visible outside of this definition or declaration
>      ssize_t (*show)(struct kobject *kobj, struct device *dev, char *buf);
>                             ^~~~~~~
>    include/linux/mdev.h:71:26: warning: 'struct kobject' declared inside parameter list will not be visible outside of this definition or declaration
>      ssize_t (*store)(struct kobject *kobj, struct device *dev,
>                              ^~~~~~~
> >> include/linux/mdev.h:98:23: error: field 'driver' has incomplete type
>      struct device_driver driver;
>                           ^~~~~~
> >> include/linux/mdev.h:106:7: error: unknown type name 'guid_t'
>     const guid_t *mdev_uuid(struct mdev_device *mdev);
>           ^~~~~~
>    In file included from <command-line>:0:0:
> >> include/linux/vfio_mdev.h:50:47: warning: 'struct vm_area_struct' declared inside parameter list will not be visible outside of this definition or declaration
>      int (*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
>                                                   ^~~~~~~~~~~~~~
> 
> vim +/attr +69 include/linux/mdev.h
> 
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   14  
> 8ac13175cbe985 Lu Baolu        2019-04-12   15  /*
> 8ac13175cbe985 Lu Baolu        2019-04-12   16   * Called by the parent device driver to set the device which represents
> 8ac13175cbe985 Lu Baolu        2019-04-12   17   * this mdev in iommu protection scope. By default, the iommu device is
> 8ac13175cbe985 Lu Baolu        2019-04-12   18   * NULL, that indicates using vendor defined isolation.
> 8ac13175cbe985 Lu Baolu        2019-04-12   19   *
> 8ac13175cbe985 Lu Baolu        2019-04-12   20   * @dev: the mediated device that iommu will isolate.
> 8ac13175cbe985 Lu Baolu        2019-04-12   21   * @iommu_device: a pci device which represents the iommu for @dev.
> 8ac13175cbe985 Lu Baolu        2019-04-12   22   *
> 8ac13175cbe985 Lu Baolu        2019-04-12   23   * Return 0 for success, otherwise negative error value.
> 8ac13175cbe985 Lu Baolu        2019-04-12   24   */
> 8ac13175cbe985 Lu Baolu        2019-04-12  @25  int mdev_set_iommu_device(struct device *dev, struct device *iommu_device);
> 8ac13175cbe985 Lu Baolu        2019-04-12   26  
> 8ac13175cbe985 Lu Baolu        2019-04-12   27  struct device *mdev_get_iommu_device(struct device *dev);
> 8ac13175cbe985 Lu Baolu        2019-04-12   28  
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   29  /**
> 42930553a7c11f Alex Williamson 2016-12-30   30   * struct mdev_parent_ops - Structure to be registered for each parent device to
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   31   * register the device to mdev module.
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   32   *
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   33   * @owner:		The module owner.
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   34   * @dev_attr_groups:	Attributes of the parent device.
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   35   * @mdev_attr_groups:	Attributes of the mediated device.
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   36   * @supported_type_groups: Attributes to define supported types. It is mandatory
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   37   *			to provide supported types.
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   38   * @create:		Called to allocate basic resources in parent device's
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   39   *			driver for a particular mediated device. It is
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   40   *			mandatory to provide create ops.
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   41   *			@kobj: kobject of type for which 'create' is called.
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   42   *			@mdev: mdev_device structure on of mediated device
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   43   *			      that is being created
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   44   *			Returns integer: success (0) or error (< 0)
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   45   * @remove:		Called to free resources in parent device's driver for a
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   46   *			a mediated device. It is mandatory to provide 'remove'
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   47   *			ops.
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   48   *			@mdev: mdev_device device structure which is being
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   49   *			       destroyed
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   50   *			Returns integer: success (0) or error (< 0)
> 0baad8a6f6fefa Jason Wang      2019-09-23   51   * @device_ops:         Device specific emulation callback.
> 0baad8a6f6fefa Jason Wang      2019-09-23   52   *
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   53   * Parent device that support mediated device should be registered with mdev
> 42930553a7c11f Alex Williamson 2016-12-30   54   * module with mdev_parent_ops structure.
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   55   **/
> 42930553a7c11f Alex Williamson 2016-12-30   56  struct mdev_parent_ops {
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   57  	struct module   *owner;
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   58  	const struct attribute_group **dev_attr_groups;
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   59  	const struct attribute_group **mdev_attr_groups;
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   60  	struct attribute_group **supported_type_groups;
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   61  
> 7b96953bc640b6 Kirti Wankhede  2016-11-17  @62  	int     (*create)(struct kobject *kobj, struct mdev_device *mdev);
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   63  	int     (*remove)(struct mdev_device *mdev);
> 0baad8a6f6fefa Jason Wang      2019-09-23   64  	const void *device_ops;
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   65  };
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   66  
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   67  /* interface for exporting mdev supported type attributes */
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   68  struct mdev_type_attribute {
> 7b96953bc640b6 Kirti Wankhede  2016-11-17  @69  	struct attribute attr;
> 7b96953bc640b6 Kirti Wankhede  2016-11-17  @70  	ssize_t (*show)(struct kobject *kobj, struct device *dev, char *buf);
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   71  	ssize_t (*store)(struct kobject *kobj, struct device *dev,
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   72  			 const char *buf, size_t count);
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   73  };
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   74  
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   75  #define MDEV_TYPE_ATTR(_name, _mode, _show, _store)		\
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   76  struct mdev_type_attribute mdev_type_attr_##_name =		\
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   77  	__ATTR(_name, _mode, _show, _store)
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   78  #define MDEV_TYPE_ATTR_RW(_name) \
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   79  	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RW(_name)
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   80  #define MDEV_TYPE_ATTR_RO(_name) \
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   81  	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RO(_name)
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   82  #define MDEV_TYPE_ATTR_WO(_name) \
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   83  	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_WO(_name)
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   84  
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   85  /**
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   86   * struct mdev_driver - Mediated device driver
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   87   * @name: driver name
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   88   * @probe: called when new device created
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   89   * @remove: called when device removed
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   90   * @driver: device driver structure
> 6294ee8e0b5153 Jason Wang      2019-09-23   91   * @id_table: the ids serviced by this driver.
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   92   *
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   93   **/
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   94  struct mdev_driver {
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   95  	const char *name;
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   96  	int  (*probe)(struct device *dev);
> 7b96953bc640b6 Kirti Wankhede  2016-11-17   97  	void (*remove)(struct device *dev);
> 7b96953bc640b6 Kirti Wankhede  2016-11-17  @98  	struct device_driver driver;
> 6294ee8e0b5153 Jason Wang      2019-09-23   99  	const struct mdev_class_id *id_table;
> 7b96953bc640b6 Kirti Wankhede  2016-11-17  100  };
> 7b96953bc640b6 Kirti Wankhede  2016-11-17  101  
> 7b96953bc640b6 Kirti Wankhede  2016-11-17  102  #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
> 7b96953bc640b6 Kirti Wankhede  2016-11-17  103  
> 50732af3b65691 Parav Pandit    2019-04-30  104  void *mdev_get_drvdata(struct mdev_device *mdev);
> 50732af3b65691 Parav Pandit    2019-04-30  105  void mdev_set_drvdata(struct mdev_device *mdev, void *data);
> 50732af3b65691 Parav Pandit    2019-04-30 @106  const guid_t *mdev_uuid(struct mdev_device *mdev);
> 7b96953bc640b6 Kirti Wankhede  2016-11-17  107  
> 
> :::::: The code at line 69 was first introduced by commit
> :::::: 7b96953bc640b6b25665fe17ffca4b668b371f14 vfio: Mediated device Core driver
> 
> :::::: TO: Kirti Wankhede <kwankhede@nvidia.com>
> :::::: CC: Alex Williamson <alex.williamson@redhat.com>
> 
> ---
> 0-DAY kernel test infrastructure                Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

Re: [PATCH 5/6] vringh: fix copy direction of vringh_iov_push_kern()

[Alex Williamson]

On Mon, 23 Sep 2019 21:03:30 +0800
Jason Wang <jasowang@redhat.com> wrote:

> We want to copy from iov to buf, so the direction was wrong.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  drivers/vhost/vringh.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)


Why is this included in the series?  Seems like an unrelated fix being
held up within a proposal for a new feature.  Thanks,

Alex
 
> diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
> index 08ad0d1f0476..a0a2d74967ef 100644
> --- a/drivers/vhost/vringh.c
> +++ b/drivers/vhost/vringh.c
> @@ -852,6 +852,12 @@ static inline int xfer_kern(void *src, void *dst, size_t len)
>  	return 0;
>  }
>  
> +static inline int kern_xfer(void *dst, void *src, size_t len)
> +{
> +	memcpy(dst, src, len);
> +	return 0;
> +}
> +
>  /**
>   * vringh_init_kern - initialize a vringh for a kernelspace vring.
>   * @vrh: the vringh to initialize.
> @@ -958,7 +964,7 @@ EXPORT_SYMBOL(vringh_iov_pull_kern);
>  ssize_t vringh_iov_push_kern(struct vringh_kiov *wiov,
>  			     const void *src, size_t len)
>  {
> -	return vringh_iov_xfer(wiov, (void *)src, len, xfer_kern);
> +	return vringh_iov_xfer(wiov, (void *)src, len, kern_xfer);
>  }
>  EXPORT_SYMBOL(vringh_iov_push_kern);
>  

Re: [PATCH 5/6] vringh: fix copy direction of vringh_iov_push_kern()

[Michael S. Tsirkin]

On Mon, Sep 23, 2019 at 09:45:59AM -0600, Alex Williamson wrote:
> On Mon, 23 Sep 2019 21:03:30 +0800
> Jason Wang <jasowang@redhat.com> wrote:
> 
> > We want to copy from iov to buf, so the direction was wrong.
> > 
> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > ---
> >  drivers/vhost/vringh.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> 
> Why is this included in the series?  Seems like an unrelated fix being
> held up within a proposal for a new feature.  Thanks,
> 
> Alex

It's better to have it as patch 1/6, but it's a dependency of the
example driver in the series. I can reorder when I apply.


> > diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
> > index 08ad0d1f0476..a0a2d74967ef 100644
> > --- a/drivers/vhost/vringh.c
> > +++ b/drivers/vhost/vringh.c
> > @@ -852,6 +852,12 @@ static inline int xfer_kern(void *src, void *dst, size_t len)
> >  	return 0;
> >  }
> >  
> > +static inline int kern_xfer(void *dst, void *src, size_t len)
> > +{
> > +	memcpy(dst, src, len);
> > +	return 0;
> > +}
> > +
> >  /**
> >   * vringh_init_kern - initialize a vringh for a kernelspace vring.
> >   * @vrh: the vringh to initialize.
> > @@ -958,7 +964,7 @@ EXPORT_SYMBOL(vringh_iov_pull_kern);
> >  ssize_t vringh_iov_push_kern(struct vringh_kiov *wiov,
> >  			     const void *src, size_t len)
> >  {
> > -	return vringh_iov_xfer(wiov, (void *)src, len, xfer_kern);
> > +	return vringh_iov_xfer(wiov, (void *)src, len, kern_xfer);
> >  }
> >  EXPORT_SYMBOL(vringh_iov_push_kern);
> >  

Re: [PATCH 1/6] mdev: class id support

[Alex Williamson]

On Mon, 23 Sep 2019 21:03:26 +0800
Jason Wang <jasowang@redhat.com> wrote:

> 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


>  	if (!mdev_bus_compat_class) {
>  		mdev_bus_compat_class = class_compat_register("mdev_bus");
> @@ -208,7 +212,13 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
>  		put_device(dev);
>  	return ret;
>  }
> -EXPORT_SYMBOL(mdev_register_device);
> +
> +int mdev_register_vfio_device(struct device *dev,
> +			      const struct mdev_parent_ops *ops)
> +{
> +	return mdev_register_device(dev, ops, MDEV_ID_VFIO);
> +}
> +EXPORT_SYMBOL(mdev_register_vfio_device);
>  
>  /*
>   * mdev_unregister_device : Unregister a parent device
> diff --git a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
> index 0d3223aee20b..b70bbebc9dd3 100644
> --- a/drivers/vfio/mdev/mdev_driver.c
> +++ b/drivers/vfio/mdev/mdev_driver.c
> @@ -69,8 +69,22 @@ static int mdev_remove(struct device *dev)
>  	return 0;
>  }
>  
> +static int mdev_match(struct device *dev, struct device_driver *drv)
> +{
> +	unsigned int i;
> +	struct mdev_device *mdev = to_mdev_device(dev);
> +	struct mdev_driver *mdrv = to_mdev_driver(drv);
> +	const struct mdev_class_id *ids = mdrv->id_table;
> +
> +	for (i = 0; ids[i].id; i++)
> +		if (ids[i].id == mdev->parent->class_id)
> +			return 1;
> +	return 0;
> +}
> +
>  struct bus_type mdev_bus_type = {
>  	.name		= "mdev",
> +	.match		= mdev_match,
>  	.probe		= mdev_probe,
>  	.remove		= mdev_remove,
>  };
> diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
> index 7d922950caaf..e58b07c866b1 100644
> --- a/drivers/vfio/mdev/mdev_private.h
> +++ b/drivers/vfio/mdev/mdev_private.h
> @@ -22,6 +22,7 @@ struct mdev_parent {
>  	struct list_head type_list;
>  	/* Synchronize device creation/removal with parent unregistration */
>  	struct rw_semaphore unreg_sem;
> +	u8 class_id;
>  };
>  
>  struct mdev_device {
> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
> index 30964a4e0a28..fd2a4d9a3f26 100644
> --- a/drivers/vfio/mdev/vfio_mdev.c
> +++ b/drivers/vfio/mdev/vfio_mdev.c
> @@ -120,10 +120,16 @@ static void vfio_mdev_remove(struct device *dev)
>  	vfio_del_group_dev(dev);
>  }
>  
> +static struct mdev_class_id id_table[] = {
> +	{ MDEV_ID_VFIO },
> +	{ 0 },
> +};
> +
>  static struct mdev_driver vfio_mdev_driver = {
>  	.name	= "vfio_mdev",
>  	.probe	= vfio_mdev_probe,
>  	.remove	= vfio_mdev_remove,
> +	.id_table = id_table,
>  };
>  
>  static int __init vfio_mdev_init(void)
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> index 0ce30ca78db0..3ebae310f599 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -118,6 +118,7 @@ struct mdev_type_attribute mdev_type_attr_##_name =		\
>   * @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 {
> @@ -125,6 +126,7 @@ struct mdev_driver {
>  	int  (*probe)(struct device *dev);
>  	void (*remove)(struct device *dev);
>  	struct device_driver driver;
> +	const struct mdev_class_id *id_table;
>  };
>  
>  #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
> @@ -135,7 +137,8 @@ const guid_t *mdev_uuid(struct mdev_device *mdev);
>  
>  extern struct bus_type mdev_bus_type;
>  
> -int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops);
> +int mdev_register_vfio_device(struct device *dev,
> +			      const struct mdev_parent_ops *ops);
>  void mdev_unregister_device(struct device *dev);
>  
>  int mdev_register_driver(struct mdev_driver *drv, struct module *owner);
> @@ -145,4 +148,6 @@ struct device *mdev_parent_dev(struct mdev_device *mdev);
>  struct device *mdev_dev(struct mdev_device *mdev);
>  struct mdev_device *mdev_from_dev(struct device *dev);
>  
> +#define MDEV_ID_VFIO 1 /* VFIO device */
> +
>  #endif /* MDEV_H */
> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> index 5714fd35a83c..f32c6e44fb1a 100644
> --- a/include/linux/mod_devicetable.h
> +++ b/include/linux/mod_devicetable.h
> @@ -821,4 +821,12 @@ struct wmi_device_id {
>  	const void *context;
>  };
>  
> +/**
> + * struct mdev_class_id - MDEV device class identifier
> + * @id: Used to identify a specific class of device, e.g vfio-mdev device.
> + */
> +struct mdev_class_id {
> +	__u16 id;
> +};
> +
>  #endif /* LINUX_MOD_DEVICETABLE_H */
> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
> index ac5c8c17b1ff..71a4469be85d 100644
> --- a/samples/vfio-mdev/mbochs.c
> +++ b/samples/vfio-mdev/mbochs.c
> @@ -1468,7 +1468,7 @@ static int __init mbochs_dev_init(void)
>  	if (ret)
>  		goto failed2;
>  
> -	ret = mdev_register_device(&mbochs_dev, &mdev_fops);
> +	ret = mdev_register_vfio_device(&mbochs_dev, &mdev_fops);
>  	if (ret)
>  		goto failed3;
>  
> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
> index cc86bf6566e4..d3029dd27d91 100644
> --- a/samples/vfio-mdev/mdpy.c
> +++ b/samples/vfio-mdev/mdpy.c
> @@ -775,7 +775,7 @@ static int __init mdpy_dev_init(void)
>  	if (ret)
>  		goto failed2;
>  
> -	ret = mdev_register_device(&mdpy_dev, &mdev_fops);
> +	ret = mdev_register_vfio_device(&mdpy_dev, &mdev_fops);
>  	if (ret)
>  		goto failed3;
>  
> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
> index 92e770a06ea2..744c88a6b22c 100644
> --- a/samples/vfio-mdev/mtty.c
> +++ b/samples/vfio-mdev/mtty.c
> @@ -1468,7 +1468,7 @@ static int __init mtty_dev_init(void)
>  	if (ret)
>  		goto failed2;
>  
> -	ret = mdev_register_device(&mtty_dev.dev, &mdev_fops);
> +	ret = mdev_register_vfio_device(&mtty_dev.dev, &mdev_fops);
>  	if (ret)
>  		goto failed3;
>  

RE: [PATCH 1/6] mdev: class id support

[Parav Pandit]

Hi Jason,

> -----Original Message-----
> From: Jason Wang <jasowang@redhat.com>
> Sent: Monday, September 23, 2019 8:03 AM
> To: kvm@vger.kernel.org; linux-s390@vger.kernel.org; linux-
> kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; intel-
> gfx@lists.freedesktop.org; intel-gvt-dev@lists.freedesktop.org;
> kwankhede@nvidia.com; alex.williamson@redhat.com; mst@redhat.com;
> tiwei.bie@intel.com
> Cc: virtualization@lists.linux-foundation.org; netdev@vger.kernel.org;
> cohuck@redhat.com; maxime.coquelin@redhat.com;
> cunming.liang@intel.com; zhihong.wang@intel.com;
> rob.miller@broadcom.com; xiao.w.wang@intel.com;
> haotian.wang@sifive.com; zhenyuw@linux.intel.com; zhi.a.wang@intel.com;
> jani.nikula@linux.intel.com; joonas.lahtinen@linux.intel.com;
> rodrigo.vivi@intel.com; airlied@linux.ie; daniel@ffwll.ch;
> farman@linux.ibm.com; pasic@linux.ibm.com; sebott@linux.ibm.com;
> oberpar@linux.ibm.com; heiko.carstens@de.ibm.com; gor@linux.ibm.com;
> borntraeger@de.ibm.com; akrowiak@linux.ibm.com; freude@linux.ibm.com;
> lingshan.zhu@intel.com; Ido Shamay <idos@mellanox.com>;
> eperezma@redhat.com; lulu@redhat.com; Parav Pandit
> <parav@mellanox.com>; Jason Wang <jasowang@redhat.com>
> Subject: [PATCH 1/6] mdev: class id support
> 
> 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.
No full stop at the end.

>        */
>       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);
> 
Unrelated change in this patch.

>  * 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);
> 
Cover letter from Change-V2 says that it class_id changed from " use u16 instead u8 for class id"
But it is still u8 here?

>  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.
>   *
It device id here, but in below its class_id. Please make them uniform.

>   * 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)
>  {
u16 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;
> 
>  	if (!mdev_bus_compat_class) {
>  		mdev_bus_compat_class =
> class_compat_register("mdev_bus");
> @@ -208,7 +212,13 @@ int mdev_register_device(struct device *dev, const
> struct mdev_parent_ops *ops)
>  		put_device(dev);
>  	return ret;
>  }
> -EXPORT_SYMBOL(mdev_register_device);
> +
> +int mdev_register_vfio_device(struct device *dev,
> +			      const struct mdev_parent_ops *ops) {
> +	return mdev_register_device(dev, ops, MDEV_ID_VFIO); }
> +EXPORT_SYMBOL(mdev_register_vfio_device);
> 
>  /*
>   * mdev_unregister_device : Unregister a parent device diff --git
> a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c index
> 0d3223aee20b..b70bbebc9dd3 100644
> --- a/drivers/vfio/mdev/mdev_driver.c
> +++ b/drivers/vfio/mdev/mdev_driver.c
> @@ -69,8 +69,22 @@ static int mdev_remove(struct device *dev)
>  	return 0;
>  }
> 
> +static int mdev_match(struct device *dev, struct device_driver *drv) {
> +	unsigned int i;
> +	struct mdev_device *mdev = to_mdev_device(dev);
> +	struct mdev_driver *mdrv = to_mdev_driver(drv);
> +	const struct mdev_class_id *ids = mdrv->id_table;
> +
> +	for (i = 0; ids[i].id; i++)
> +		if (ids[i].id == mdev->parent->class_id)
> +			return 1;
> +	return 0;
> +}
> +
>  struct bus_type mdev_bus_type = {
>  	.name		= "mdev",
> +	.match		= mdev_match,
>  	.probe		= mdev_probe,
>  	.remove		= mdev_remove,
>  };
> diff --git a/drivers/vfio/mdev/mdev_private.h
> b/drivers/vfio/mdev/mdev_private.h
> index 7d922950caaf..e58b07c866b1 100644
> --- a/drivers/vfio/mdev/mdev_private.h
> +++ b/drivers/vfio/mdev/mdev_private.h
> @@ -22,6 +22,7 @@ struct mdev_parent {
>  	struct list_head type_list;
>  	/* Synchronize device creation/removal with parent unregistration */
>  	struct rw_semaphore unreg_sem;
> +	u8 class_id;
>  };
> 
>  struct mdev_device {
> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
> index 30964a4e0a28..fd2a4d9a3f26 100644
> --- a/drivers/vfio/mdev/vfio_mdev.c
> +++ b/drivers/vfio/mdev/vfio_mdev.c
> @@ -120,10 +120,16 @@ static void vfio_mdev_remove(struct device *dev)
>  	vfio_del_group_dev(dev);
>  }
> 
> +static struct mdev_class_id id_table[] = {
> +	{ MDEV_ID_VFIO },
> +	{ 0 },
> +};
> +
>  static struct mdev_driver vfio_mdev_driver = {
>  	.name	= "vfio_mdev",
>  	.probe	= vfio_mdev_probe,
>  	.remove	= vfio_mdev_remove,
> +	.id_table = id_table,
>  };
> 
>  static int __init vfio_mdev_init(void)
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h index
> 0ce30ca78db0..3ebae310f599 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -118,6 +118,7 @@ struct mdev_type_attribute mdev_type_attr_##_name
> =		\
>   * @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 {
> @@ -125,6 +126,7 @@ struct mdev_driver {
>  	int  (*probe)(struct device *dev);
>  	void (*remove)(struct device *dev);
>  	struct device_driver driver;
> +	const struct mdev_class_id *id_table;
>  };
> 
>  #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
> @@ -135,7 +137,8 @@ const guid_t *mdev_uuid(struct mdev_device *mdev);
> 
>  extern struct bus_type mdev_bus_type;
> 
> -int mdev_register_device(struct device *dev, const struct mdev_parent_ops
> *ops);
> +int mdev_register_vfio_device(struct device *dev,
> +			      const struct mdev_parent_ops *ops);
>  void mdev_unregister_device(struct device *dev);
> 
>  int mdev_register_driver(struct mdev_driver *drv, struct module *owner);
> @@ -145,4 +148,6 @@ struct device *mdev_parent_dev(struct mdev_device
> *mdev);  struct device *mdev_dev(struct mdev_device *mdev);  struct
> mdev_device *mdev_from_dev(struct device *dev);
> 
> +#define MDEV_ID_VFIO 1 /* VFIO device */
> +
Instead of define, please put them as enum 

enum mdev_class/device_id {
	MDEV_ID_VFIO = 1,
	/* New entries must be added here */
};

>  #endif /* MDEV_H */
> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> index 5714fd35a83c..f32c6e44fb1a 100644
> --- a/include/linux/mod_devicetable.h
> +++ b/include/linux/mod_devicetable.h
> @@ -821,4 +821,12 @@ struct wmi_device_id {
>  	const void *context;
>  };
> 
> +/**
> + * struct mdev_class_id - MDEV device class identifier
> + * @id: Used to identify a specific class of device, e.g vfio-mdev device.
> + */
> +struct mdev_class_id {
> +	__u16 id;
> +};
This is u16 as I guess you wanted as opposed to u8 in other places in patch.

> +
>  #endif /* LINUX_MOD_DEVICETABLE_H */
> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c index
> ac5c8c17b1ff..71a4469be85d 100644
> --- a/samples/vfio-mdev/mbochs.c
> +++ b/samples/vfio-mdev/mbochs.c
> @@ -1468,7 +1468,7 @@ static int __init mbochs_dev_init(void)
>  	if (ret)
>  		goto failed2;
> 
> -	ret = mdev_register_device(&mbochs_dev, &mdev_fops);
> +	ret = mdev_register_vfio_device(&mbochs_dev, &mdev_fops);
>  	if (ret)
>  		goto failed3;
> 
> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index
> cc86bf6566e4..d3029dd27d91 100644
> --- a/samples/vfio-mdev/mdpy.c
> +++ b/samples/vfio-mdev/mdpy.c
> @@ -775,7 +775,7 @@ static int __init mdpy_dev_init(void)
>  	if (ret)
>  		goto failed2;
> 
> -	ret = mdev_register_device(&mdpy_dev, &mdev_fops);
> +	ret = mdev_register_vfio_device(&mdpy_dev, &mdev_fops);
>  	if (ret)
>  		goto failed3;
> 
> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c index
> 92e770a06ea2..744c88a6b22c 100644
> --- a/samples/vfio-mdev/mtty.c
> +++ b/samples/vfio-mdev/mtty.c
> @@ -1468,7 +1468,7 @@ static int __init mtty_dev_init(void)
>  	if (ret)
>  		goto failed2;
> 
> -	ret = mdev_register_device(&mtty_dev.dev, &mdev_fops);
> +	ret = mdev_register_vfio_device(&mtty_dev.dev, &mdev_fops);
>  	if (ret)
>  		goto failed3;
> 
> --
> 2.19.1

RE: [PATCH 1/6] mdev: class id support

[Parav Pandit]

Hi Jason,


> -----Original Message-----
> From: Jason Wang <jasowang@redhat.com>
> Sent: Monday, September 23, 2019 8:03 AM
> To: kvm@vger.kernel.org; linux-s390@vger.kernel.org; linux-
> kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; intel-
> gfx@lists.freedesktop.org; intel-gvt-dev@lists.freedesktop.org;
> kwankhede@nvidia.com; alex.williamson@redhat.com; mst@redhat.com;
> tiwei.bie@intel.com
> Cc: virtualization@lists.linux-foundation.org; netdev@vger.kernel.org;
> cohuck@redhat.com; maxime.coquelin@redhat.com;
> cunming.liang@intel.com; zhihong.wang@intel.com;
> rob.miller@broadcom.com; xiao.w.wang@intel.com;
> haotian.wang@sifive.com; zhenyuw@linux.intel.com; zhi.a.wang@intel.com;
> jani.nikula@linux.intel.com; joonas.lahtinen@linux.intel.com;
> rodrigo.vivi@intel.com; airlied@linux.ie; daniel@ffwll.ch;
> farman@linux.ibm.com; pasic@linux.ibm.com; sebott@linux.ibm.com;
> oberpar@linux.ibm.com; heiko.carstens@de.ibm.com; gor@linux.ibm.com;
> borntraeger@de.ibm.com; akrowiak@linux.ibm.com; freude@linux.ibm.com;
> lingshan.zhu@intel.com; Ido Shamay <idos@mellanox.com>;
> eperezma@redhat.com; lulu@redhat.com; Parav Pandit
> <parav@mellanox.com>; Jason Wang <jasowang@redhat.com>
> Subject: [PATCH 1/6] mdev: class id support
> 
> 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(-)
> 
You additionally need modpost support for id table integration to modifo, modprobe and other tools.
A small patch similar to this one [1] is needed.
Please include in the series.

[1] https://lore.kernel.org/patchwork/patch/1046991/

RE: [PATCH 4/6] virtio: introduce a mdev based transport

[Parav Pandit]

> -----Original Message-----
> From: Jason Wang <jasowang@redhat.com>
> Sent: Monday, September 23, 2019 8:03 AM
> To: kvm@vger.kernel.org; linux-s390@vger.kernel.org; linux-
> kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; intel-
> gfx@lists.freedesktop.org; intel-gvt-dev@lists.freedesktop.org;
> kwankhede@nvidia.com; alex.williamson@redhat.com; mst@redhat.com;
> tiwei.bie@intel.com
> Cc: virtualization@lists.linux-foundation.org; netdev@vger.kernel.org;
> cohuck@redhat.com; maxime.coquelin@redhat.com;
> cunming.liang@intel.com; zhihong.wang@intel.com;
> rob.miller@broadcom.com; xiao.w.wang@intel.com;
> haotian.wang@sifive.com; zhenyuw@linux.intel.com; zhi.a.wang@intel.com;
> jani.nikula@linux.intel.com; joonas.lahtinen@linux.intel.com;
> rodrigo.vivi@intel.com; airlied@linux.ie; daniel@ffwll.ch;
> farman@linux.ibm.com; pasic@linux.ibm.com; sebott@linux.ibm.com;
> oberpar@linux.ibm.com; heiko.carstens@de.ibm.com; gor@linux.ibm.com;
> borntraeger@de.ibm.com; akrowiak@linux.ibm.com; freude@linux.ibm.com;
> lingshan.zhu@intel.com; Ido Shamay <idos@mellanox.com>;
> eperezma@redhat.com; lulu@redhat.com; Parav Pandit
> <parav@mellanox.com>; Jason Wang <jasowang@redhat.com>
> Subject: [PATCH 4/6] virtio: introduce a mdev based transport
> 
> This patch introduces a new mdev transport for virtio. This is used to use kernel
> virtio driver to drive the mediated device that is capable of populating
> virtqueue directly.
> 
> A new virtio-mdev driver will be registered to the mdev bus, when a new virtio-
> mdev device is probed, it will register the device with mdev based config ops.
> This means it is a software transport between mdev driver and mdev device.
> The transport was implemented through device specific opswhich is a part of
> mdev_parent_ops now.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  MAINTAINERS                     |   1 +
>  drivers/vfio/mdev/Kconfig       |   7 +
>  drivers/vfio/mdev/Makefile      |   1 +
>  drivers/vfio/mdev/virtio_mdev.c | 416 ++++++++++++++++++++++++++++++++
>  4 files changed, 425 insertions(+)
>  create mode 100644 drivers/vfio/mdev/virtio_mdev.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 89832b316500..820ec250cc52 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -17202,6 +17202,7 @@ F:	include/linux/virtio*.h
>  F:	include/uapi/linux/virtio_*.h
>  F:	drivers/crypto/virtio/
>  F:	mm/balloon_compaction.c
> +F:	drivers/vfio/mdev/virtio_mdev.c
> 
>  VIRTIO BLOCK AND SCSI DRIVERS
>  M:	"Michael S. Tsirkin" <mst@redhat.com>
> diff --git a/drivers/vfio/mdev/Kconfig b/drivers/vfio/mdev/Kconfig index
> 5da27f2100f9..c488c31fc137 100644
> --- a/drivers/vfio/mdev/Kconfig
> +++ b/drivers/vfio/mdev/Kconfig
> @@ -16,3 +16,10 @@ config VFIO_MDEV_DEVICE
>  	default n
>  	help
>  	  VFIO based driver for Mediated devices.
> +
> +config VIRTIO_MDEV_DEVICE
> +	tristate "VIRTIO driver for Mediated devices"
> +	depends on VFIO_MDEV && VIRTIO
> +	default n
> +	help
> +	  VIRTIO based driver for Mediated devices.
> diff --git a/drivers/vfio/mdev/Makefile b/drivers/vfio/mdev/Makefile index
> 101516fdf375..99d31e29c23e 100644
> --- a/drivers/vfio/mdev/Makefile
> +++ b/drivers/vfio/mdev/Makefile
> @@ -4,3 +4,4 @@ mdev-y := mdev_core.o mdev_sysfs.o mdev_driver.o
> 
>  obj-$(CONFIG_VFIO_MDEV) += mdev.o
>  obj-$(CONFIG_VFIO_MDEV_DEVICE) += vfio_mdev.o
> +obj-$(CONFIG_VIRTIO_MDEV_DEVICE) += virtio_mdev.o
> diff --git a/drivers/vfio/mdev/virtio_mdev.c b/drivers/vfio/mdev/virtio_mdev.c
> new file mode 100644 index 000000000000..919a082adc9c
> --- /dev/null
> +++ b/drivers/vfio/mdev/virtio_mdev.c
> @@ -0,0 +1,416 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * VIRTIO based driver for Mediated device
> + *
> + * Copyright (c) 2019, Red Hat. All rights reserved.
> + *     Author: Jason Wang <jasowang@redhat.com>
> + *
> + */
> +
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/uuid.h>
> +#include <linux/mdev.h>
> +#include <linux/virtio_mdev.h>
> +#include <linux/virtio.h>
> +#include <linux/virtio_config.h>
> +#include <linux/virtio_ring.h>
> +#include "mdev_private.h"
> +
> +#define DRIVER_VERSION  "0.1"
> +#define DRIVER_AUTHOR   "Red Hat Corporation"
> +#define DRIVER_DESC     "VIRTIO based driver for Mediated device"
> +
> +#define to_virtio_mdev_device(dev) \
> +	container_of(dev, struct virtio_mdev_device, vdev)
> +
> +struct virtio_mdev_device {
> +	struct virtio_device vdev;
> +	struct mdev_device *mdev;
> +	unsigned long version;
> +
> +	struct virtqueue **vqs;
Every lock must need a comment to describe what it locks.
I don't see this lock is used in this patch. Please introduce in the patch that uses it.
> +	spinlock_t lock;
> +};
> +
> +struct virtio_mdev_vq_info {
> +	/* the actual virtqueue */
> +	struct virtqueue *vq;
> +
> +	/* the list node for the virtqueues list */
> +	struct list_head node;
> +};
> +
> +static struct mdev_device *vm_get_mdev(struct virtio_device *vdev) {
> +	struct virtio_mdev_device *vm_dev = to_virtio_mdev_device(vdev);
> +	struct mdev_device *mdev = vm_dev->mdev;
> +
> +	return mdev;
> +}
> +
> +static const struct virtio_mdev_parent_ops *mdev_get_parent_ops(struct
> +mdev_device *mdev) {
> +	struct mdev_parent *parent = mdev->parent;
> +
> +	return parent->ops->device_ops;
> +}
> +
> +static void virtio_mdev_get(struct virtio_device *vdev, unsigned offset,
> +			    void *buf, unsigned len)
> +{
> +	struct mdev_device *mdev = vm_get_mdev(vdev);
> +	const struct virtio_mdev_parent_ops *ops =
> mdev_get_parent_ops(mdev);
> +
> +	ops->get_config(mdev, offset, buf, len); }
> +
> +static void virtio_mdev_set(struct virtio_device *vdev, unsigned offset,
> +			    const void *buf, unsigned len)
> +{
> +	struct mdev_device *mdev = vm_get_mdev(vdev);
> +	const struct virtio_mdev_parent_ops *ops =
> mdev_get_parent_ops(mdev);
> +
> +	ops->set_config(mdev, offset, buf, len); }
> +
> +static u32 virtio_mdev_generation(struct virtio_device *vdev) {
> +	struct mdev_device *mdev = vm_get_mdev(vdev);
> +	const struct virtio_mdev_parent_ops *ops =
> mdev_get_parent_ops(mdev);
> +
> +	return ops->get_generation(mdev);
> +}
> +
> +static u8 virtio_mdev_get_status(struct virtio_device *vdev) {
> +	struct mdev_device *mdev = vm_get_mdev(vdev);
> +	const struct virtio_mdev_parent_ops *ops =
> mdev_get_parent_ops(mdev);
> +
> +	return ops->get_status(mdev);
> +}
> +
> +static void virtio_mdev_set_status(struct virtio_device *vdev, u8
> +status) {
> +	struct mdev_device *mdev = vm_get_mdev(vdev);
> +	const struct virtio_mdev_parent_ops *ops =
> mdev_get_parent_ops(mdev);
> +
> +	return ops->set_status(mdev, status);
> +}
> +
> +static void virtio_mdev_reset(struct virtio_device *vdev) {
> +	struct mdev_device *mdev = vm_get_mdev(vdev);
> +	const struct virtio_mdev_parent_ops *ops =
> mdev_get_parent_ops(mdev);
> +
> +	return ops->set_status(mdev, 0);
> +}
> +
> +static bool virtio_mdev_notify(struct virtqueue *vq) {
> +	struct mdev_device *mdev = vm_get_mdev(vq->vdev);
> +	const struct virtio_mdev_parent_ops *ops =
> mdev_get_parent_ops(mdev);
> +
> +	ops->kick_vq(mdev, vq->index);
> +
> +	return true;
> +}
> +
> +static irqreturn_t virtio_mdev_config_cb(void *private) {
> +	struct virtio_mdev_device *vm_dev = private;
> +
> +	virtio_config_changed(&vm_dev->vdev);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t virtio_mdev_virtqueue_cb(void *private) {
> +	struct virtio_mdev_vq_info *info = private;
> +
> +	return vring_interrupt(0, info->vq);
> +}
> +
> +static struct virtqueue *
> +virtio_mdev_setup_vq(struct virtio_device *vdev, unsigned index,
> +		     void (*callback)(struct virtqueue *vq),
> +		     const char *name, bool ctx)
> +{
> +	struct mdev_device *mdev = vm_get_mdev(vdev);
> +	const struct virtio_mdev_parent_ops *ops =
> mdev_get_parent_ops(mdev);
> +	struct virtio_mdev_vq_info *info;
> +	struct virtio_mdev_callback cb;
> +	struct virtqueue *vq;
> +	u32 align, num;
> +	u64 desc_addr, driver_addr, device_addr;
> +	int err;
> +
> +	if (!name)
> +		return NULL;
> +
> +	/* Queue shouldn't already be set up. */
> +	if (ops->get_vq_ready(mdev, index)) {
> +		err = -ENOENT;
> +		goto error_available;
> +	}
> +
No need for a goto, to single return done later.
Just do 
	if (ops->get_vq_ready(mdev, index))
		return -ENOENT;

> +	/* Allocate and fill out our active queue description */
> +	info = kmalloc(sizeof(*info), GFP_KERNEL);
> +	if (!info) {
> +		err = -ENOMEM;
> +		goto error_kmalloc;
> +	}
> +
Similar to above one.

> +	num = ops->get_queue_max(mdev);
> +	if (num == 0) {
> +		err = -ENOENT;
> +		goto error_new_virtqueue;
> +	}
> +
> +	/* Create the vring */
> +	align = ops->get_vq_align(mdev);
> +	vq = vring_create_virtqueue(index, num, align, vdev,
> +				    true, true, ctx,
> +				    virtio_mdev_notify, callback, name);
> +	if (!vq) {
> +		err = -ENOMEM;
> +		goto error_new_virtqueue;
> +	}
> +
> +	/* Setup virtqueue callback */
> +	cb.callback = virtio_mdev_virtqueue_cb;
> +	cb.private = info;
> +	ops->set_vq_cb(mdev, index, &cb);
> +	ops->set_vq_num(mdev, index, virtqueue_get_vring_size(vq));
> +
> +	desc_addr = virtqueue_get_desc_addr(vq);
> +	driver_addr = virtqueue_get_avail_addr(vq);
> +	device_addr = virtqueue_get_used_addr(vq);
> +
> +	if (ops->set_vq_address(mdev, index,
> +				desc_addr, driver_addr,
> +				device_addr)) {
> +		err = -EINVAL;
> +		goto err_vq;
> +	}
> +
> +	ops->set_vq_ready(mdev, index, 1);
> +
> +	vq->priv = info;
> +	info->vq = vq;
> +
> +	return vq;
> +
> +err_vq:
> +	vring_del_virtqueue(vq);
> +error_new_virtqueue:
> +	ops->set_vq_ready(mdev, index, 0);
> +	WARN_ON(ops->get_vq_ready(mdev, index));
> +	kfree(info);
> +error_kmalloc:
> +error_available:
> +	return ERR_PTR(err);
> +
> +}
> +
> +static void virtio_mdev_del_vq(struct virtqueue *vq) {
> +	struct mdev_device *mdev = vm_get_mdev(vq->vdev);
> +	const struct virtio_mdev_parent_ops *ops =
> mdev_get_parent_ops(mdev);
> +	struct virtio_mdev_vq_info *info = vq->priv;
> +	unsigned int index = vq->index;
> +
> +	/* Select and deactivate the queue */
> +	ops->set_vq_ready(mdev, index, 0);
> +	WARN_ON(ops->get_vq_ready(mdev, index));
> +
> +	vring_del_virtqueue(vq);
> +
> +	kfree(info);
> +}
> +
> +static void virtio_mdev_del_vqs(struct virtio_device *vdev) {
> +	struct virtqueue *vq, *n;
> +
> +	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
> +		virtio_mdev_del_vq(vq);
> +}
> +
> +static int virtio_mdev_find_vqs(struct virtio_device *vdev, unsigned nvqs,
> +				struct virtqueue *vqs[],
> +				vq_callback_t *callbacks[],
> +				const char * const names[],
> +				const bool *ctx,
> +				struct irq_affinity *desc)
> +{
> +	struct virtio_mdev_device *vm_dev = to_virtio_mdev_device(vdev);
> +	struct mdev_device *mdev = vm_get_mdev(vdev);
> +	const struct virtio_mdev_parent_ops *ops =
> mdev_get_parent_ops(mdev);
> +	struct virtio_mdev_callback cb;
> +	int i, err, queue_idx = 0;
> +
> +	vm_dev->vqs = kmalloc_array(queue_idx, sizeof(*vm_dev->vqs),
> +				    GFP_KERNEL);
> +	if (!vm_dev->vqs)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < nvqs; ++i) {
> +		if (!names[i]) {
> +			vqs[i] = NULL;
> +			continue;
> +		}
> +
> +		vqs[i] = virtio_mdev_setup_vq(vdev, queue_idx++,
> +					      callbacks[i], names[i], ctx ?
> +					      ctx[i] : false);
> +		if (IS_ERR(vqs[i])) {
> +			err = PTR_ERR(vqs[i]);
> +			goto err_setup_vq;
> +		}
> +	}
> +
> +	cb.callback = virtio_mdev_config_cb;
> +	cb.private = vm_dev;
> +	ops->set_config_cb(mdev, &cb);
> +
> +	return 0;
> +
> +err_setup_vq:
> +	kfree(vm_dev->vqs);
> +	virtio_mdev_del_vqs(vdev);
> +	return err;
> +}
> +
> +static u64 virtio_mdev_get_features(struct virtio_device *vdev) {
> +	struct mdev_device *mdev = vm_get_mdev(vdev);
> +	const struct virtio_mdev_parent_ops *ops =
> mdev_get_parent_ops(mdev);
> +
> +	return ops->get_features(mdev);
> +}
> +
> +static int virtio_mdev_finalize_features(struct virtio_device *vdev) {
> +	struct mdev_device *mdev = vm_get_mdev(vdev);
> +	const struct virtio_mdev_parent_ops *ops =
> mdev_get_parent_ops(mdev);
> +
> +	/* Give virtio_ring a chance to accept features. */
> +	vring_transport_features(vdev);
> +
> +	return ops->set_features(mdev, vdev->features); }
> +
> +static const char *virtio_mdev_bus_name(struct virtio_device *vdev) {
> +	struct virtio_mdev_device *vm_dev = to_virtio_mdev_device(vdev);
> +	struct mdev_device *mdev = vm_dev->mdev;
> +
> +	return dev_name(&mdev->dev);
> +}
> +
> +static const struct virtio_config_ops virtio_mdev_config_ops = {
> +	.get		= virtio_mdev_get,
> +	.set		= virtio_mdev_set,
> +	.generation	= virtio_mdev_generation,
> +	.get_status	= virtio_mdev_get_status,
> +	.set_status	= virtio_mdev_set_status,
> +	.reset		= virtio_mdev_reset,
> +	.find_vqs	= virtio_mdev_find_vqs,
> +	.del_vqs	= virtio_mdev_del_vqs,
> +	.get_features	= virtio_mdev_get_features,
> +	.finalize_features = virtio_mdev_finalize_features,
> +	.bus_name	= virtio_mdev_bus_name,
> +};
> +
> +static void virtio_mdev_release_dev(struct device *_d) {
> +	struct virtio_device *vdev =
> +	       container_of(_d, struct virtio_device, dev);
> +	struct virtio_mdev_device *vm_dev =
> +	       container_of(vdev, struct virtio_mdev_device, vdev);
> +
> +	devm_kfree(_d, vm_dev);
> +}
> +
> +static int virtio_mdev_probe(struct device *dev) {
> +	struct mdev_device *mdev = to_mdev_device(dev);
> +	const struct virtio_mdev_parent_ops *ops =
> mdev_get_parent_ops(mdev);
> +	struct virtio_mdev_device *vm_dev;
> +	int rc;
> +
> +	vm_dev = devm_kzalloc(dev, sizeof(*vm_dev), GFP_KERNEL);
> +	if (!vm_dev)
> +		return -ENOMEM;
> +
> +	vm_dev->vdev.dev.parent = dev;
> +	vm_dev->vdev.dev.release = virtio_mdev_release_dev;
> +	vm_dev->vdev.config = &virtio_mdev_config_ops;
> +	vm_dev->mdev = mdev;
> +	vm_dev->vqs = NULL;
> +	spin_lock_init(&vm_dev->lock);
> +
> +	vm_dev->version = ops->get_version(mdev);
> +	if (vm_dev->version != 1) {
> +		dev_err(dev, "Version %ld not supported!\n",
> +			vm_dev->version);
> +		return -ENXIO;
> +	}
> +
> +	vm_dev->vdev.id.device = ops->get_device_id(mdev);
> +	if (vm_dev->vdev.id.device == 0)
> +		return -ENODEV;
> +
> +	vm_dev->vdev.id.vendor = ops->get_vendor_id(mdev);
> +	rc = register_virtio_device(&vm_dev->vdev);
> +	if (rc)
> +		put_device(dev);
> +
> +	dev_set_drvdata(dev, vm_dev);
No need to set drvdata when there is error returned from register_virtio_device().

> +
> +	return rc;
> +
Extra line not needed.
> +}
> +
> +static void virtio_mdev_remove(struct device *dev) {
> +	struct virtio_mdev_device *vm_dev = dev_get_drvdata(dev);
> +
> +	unregister_virtio_device(&vm_dev->vdev);
> +}
> +
> +static struct mdev_class_id id_table[] = {
> +	{ MDEV_ID_VIRTIO },
> +	{ 0 },
> +};
> +
> +static struct mdev_driver virtio_mdev_driver = {
> +	.name	= "virtio_mdev",
> +	.probe	= virtio_mdev_probe,
> +	.remove	= virtio_mdev_remove,
No need for tab, just do single white space.

> +	.id_table = id_table,
> +};
> +
> +static int __init virtio_mdev_init(void) {
> +	return mdev_register_driver(&virtio_mdev_driver, THIS_MODULE); }
> +
> +static void __exit virtio_mdev_exit(void) {
> +	mdev_unregister_driver(&virtio_mdev_driver);
> +}
> +
> +module_init(virtio_mdev_init)
> +module_exit(virtio_mdev_exit)
> +
> +MODULE_VERSION(DRIVER_VERSION);
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR(DRIVER_AUTHOR);
> +MODULE_DESCRIPTION(DRIVER_DESC);
> --
> 2.19.1

RE: [PATCH 2/6] mdev: introduce device specific ops

[Parav Pandit]

> -----Original Message-----
> From: Jason Wang <jasowang@redhat.com>
> Sent: Monday, September 23, 2019 8:03 AM
> To: kvm@vger.kernel.org; linux-s390@vger.kernel.org; linux-
> kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; intel-
> gfx@lists.freedesktop.org; intel-gvt-dev@lists.freedesktop.org;
> kwankhede@nvidia.com; alex.williamson@redhat.com; mst@redhat.com;
> tiwei.bie@intel.com
> Cc: virtualization@lists.linux-foundation.org; netdev@vger.kernel.org;
> cohuck@redhat.com; maxime.coquelin@redhat.com;
> cunming.liang@intel.com; zhihong.wang@intel.com;
> rob.miller@broadcom.com; xiao.w.wang@intel.com;
> haotian.wang@sifive.com; zhenyuw@linux.intel.com; zhi.a.wang@intel.com;
> jani.nikula@linux.intel.com; joonas.lahtinen@linux.intel.com;
> rodrigo.vivi@intel.com; airlied@linux.ie; daniel@ffwll.ch;
> farman@linux.ibm.com; pasic@linux.ibm.com; sebott@linux.ibm.com;
> oberpar@linux.ibm.com; heiko.carstens@de.ibm.com; gor@linux.ibm.com;
> borntraeger@de.ibm.com; akrowiak@linux.ibm.com; freude@linux.ibm.com;
> lingshan.zhu@intel.com; Ido Shamay <idos@mellanox.com>;
> eperezma@redhat.com; lulu@redhat.com; Parav Pandit
> <parav@mellanox.com>; Jason Wang <jasowang@redhat.com>
> Subject: [PATCH 2/6] mdev: introduce device specific ops
> 
> Currently, except for the create and remove. The rest of mdev_parent_ops is
> designed for vfio-mdev driver only and may not help for kernel mdev driver.
> Follow the class id support by previous patch, this patch introduces device
> specific ops pointer inside parent ops which points to device specific ops (e.g
> vfio ops). This allows the future drivers like virtio-mdev to implement its own
> device specific ops.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  .../driver-api/vfio-mediated-device.rst       |  4 +-
>  MAINTAINERS                                   |  1 +
>  drivers/gpu/drm/i915/gvt/kvmgt.c              | 15 +++---
>  drivers/s390/cio/vfio_ccw_ops.c               | 15 ++++--
>  drivers/s390/crypto/vfio_ap_ops.c             | 11 ++--
>  drivers/vfio/mdev/vfio_mdev.c                 | 31 ++++++-----
>  include/linux/mdev.h                          | 36 ++-----------
>  include/linux/vfio_mdev.h                     | 53 +++++++++++++++++++
>  samples/vfio-mdev/mbochs.c                    | 17 +++---
>  samples/vfio-mdev/mdpy.c                      | 17 +++---
>  samples/vfio-mdev/mtty.c                      | 15 ++++--
>  11 files changed, 138 insertions(+), 77 deletions(-)  create mode 100644
> include/linux/vfio_mdev.h
> 
> diff --git a/Documentation/driver-api/vfio-mediated-device.rst
> b/Documentation/driver-api/vfio-mediated-device.rst
> index 0e052072e1d8..3ab00e48212f 100644
> --- a/Documentation/driver-api/vfio-mediated-device.rst
> +++ b/Documentation/driver-api/vfio-mediated-device.rst
> @@ -152,7 +152,9 @@ callbacks per mdev parent device, per mdev type, or
> any other categorization.
>  Vendor drivers are expected to be fully asynchronous in this respect or
> provide their own internal resource protection.)
> 
> -The callbacks in the mdev_parent_ops structure are as follows:
> +The device specific callbacks are referred through device_ops pointer
> +in mdev_parent_ops. For vfio-mdev device, its callbacks in device_ops
> +are as follows:
> 
>  * open: open callback of mediated device
>  * close: close callback of mediated device diff --git a/MAINTAINERS
> b/MAINTAINERS index b2326dece28e..89832b316500 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -17075,6 +17075,7 @@ S:	Maintained
>  F:	Documentation/driver-api/vfio-mediated-device.rst
>  F:	drivers/vfio/mdev/
>  F:	include/linux/mdev.h
> +F:	include/linux/vfio_mdev.h
>  F:	samples/vfio-mdev/
> 
>  VFIO PLATFORM DRIVER
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c
> b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 19d51a35f019..8ea86b1e69f1 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -42,6 +42,7 @@
>  #include <linux/kvm_host.h>
>  #include <linux/vfio.h>
>  #include <linux/mdev.h>
> +#include <linux/vfio_mdev.h>
>  #include <linux/debugfs.h>
> 
>  #include <linux/nospec.h>
> @@ -1600,20 +1601,22 @@ static const struct attribute_group
> *intel_vgpu_groups[] = {
>  	NULL,
>  };
> 
> -static struct mdev_parent_ops intel_vgpu_ops = {
> -	.mdev_attr_groups       = intel_vgpu_groups,
> -	.create			= intel_vgpu_create,
> -	.remove			= intel_vgpu_remove,
> -
> +static struct vfio_mdev_parent_ops intel_vfio_vgpu_ops = {

Naming it with _dev prefix as intel_vfio_vgpu_dev_ops is better to differentiate with parent_ops.

>  	.open			= intel_vgpu_open,
>  	.release		= intel_vgpu_release,
> -
>  	.read			= intel_vgpu_read,
>  	.write			= intel_vgpu_write,
>  	.mmap			= intel_vgpu_mmap,
>  	.ioctl			= intel_vgpu_ioctl,
>  };
> 
> +static struct mdev_parent_ops intel_vgpu_ops = {
> +	.mdev_attr_groups       = intel_vgpu_groups,
> +	.create			= intel_vgpu_create,
> +	.remove			= intel_vgpu_remove,
> +	.device_ops	        = &intel_vfio_vgpu_ops,
> +};
> +
>  static int kvmgt_host_init(struct device *dev, void *gvt, const void *ops)  {
>  	struct attribute **kvm_type_attrs;
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
> index 246ff0f80944..02122bbc213e 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -12,6 +12,7 @@
> 
>  #include <linux/vfio.h>
>  #include <linux/mdev.h>
> +#include <linux/vfio_mdev.h>
>  #include <linux/nospec.h>
>  #include <linux/slab.h>
> 
> @@ -574,11 +575,7 @@ static ssize_t vfio_ccw_mdev_ioctl(struct
> mdev_device *mdev,
>  	}
>  }
> 
> -static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
> -	.owner			= THIS_MODULE,
> -	.supported_type_groups  = mdev_type_groups,
> -	.create			= vfio_ccw_mdev_create,
> -	.remove			= vfio_ccw_mdev_remove,
> +static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
>  	.open			= vfio_ccw_mdev_open,
>  	.release		= vfio_ccw_mdev_release,
>  	.read			= vfio_ccw_mdev_read,
> @@ -586,6 +583,14 @@ static const struct mdev_parent_ops
> vfio_ccw_mdev_ops = {
>  	.ioctl			= vfio_ccw_mdev_ioctl,
>  };
> 
> +static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
> +	.owner			= THIS_MODULE,
> +	.supported_type_groups  = mdev_type_groups,
> +	.create			= vfio_ccw_mdev_create,
> +	.remove			= vfio_ccw_mdev_remove,
> +	.device_ops		= &vfio_mdev_ops,
> +};
> +
>  int vfio_ccw_mdev_reg(struct subchannel *sch)  {
>  	return mdev_register_vfio_device(&sch->dev, &vfio_ccw_mdev_ops);
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c
> b/drivers/s390/crypto/vfio_ap_ops.c
> index 7487fc39d2c5..4251becc7a6d 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -16,6 +16,7 @@
>  #include <linux/bitops.h>
>  #include <linux/kvm_host.h>
>  #include <linux/module.h>
> +#include <linux/vfio_mdev.h>
>  #include <asm/kvm.h>
>  #include <asm/zcrypt.h>
> 
> @@ -1280,15 +1281,19 @@ static ssize_t vfio_ap_mdev_ioctl(struct
> mdev_device *mdev,
>  	return ret;
>  }
> 
> +static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
> +	.open			= vfio_ap_mdev_open,
> +	.release		= vfio_ap_mdev_release,
> +	.ioctl			= vfio_ap_mdev_ioctl,
> +};
> +
>  static const struct mdev_parent_ops vfio_ap_matrix_ops = {
>  	.owner			= THIS_MODULE,
>  	.supported_type_groups	= vfio_ap_mdev_type_groups,
>  	.mdev_attr_groups	= vfio_ap_mdev_attr_groups,
>  	.create			= vfio_ap_mdev_create,
>  	.remove			= vfio_ap_mdev_remove,
> -	.open			= vfio_ap_mdev_open,
> -	.release		= vfio_ap_mdev_release,
> -	.ioctl			= vfio_ap_mdev_ioctl,
> +	.device_ops		= &vfio_mdev_ops,
>  };
> 
>  int vfio_ap_mdev_register(void)
> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
> index fd2a4d9a3f26..d23c9f58c84f 100644
> --- a/drivers/vfio/mdev/vfio_mdev.c
> +++ b/drivers/vfio/mdev/vfio_mdev.c
> @@ -14,6 +14,7 @@
>  #include <linux/slab.h>
>  #include <linux/vfio.h>
>  #include <linux/mdev.h>
> +#include <linux/vfio_mdev.h>
> 
>  #include "mdev_private.h"
> 
> @@ -25,15 +26,16 @@ static int vfio_mdev_open(void *device_data)  {
>  	struct mdev_device *mdev = device_data;
>  	struct mdev_parent *parent = mdev->parent;
> +	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
>  	int ret;
> 
> -	if (unlikely(!parent->ops->open))
> +	if (unlikely(!ops->open))
>  		return -EINVAL;
> 
device_ops is optional and can be NULL for mdev devices which are not required to be mapped via vfio.
So please change to,

If (!ops || !ops->open)
	return -EINVAL;

and rest of the below places.

>  	if (!try_module_get(THIS_MODULE))
>  		return -ENODEV;
> 
> -	ret = parent->ops->open(mdev);
> +	ret = ops->open(mdev);
>  	if (ret)
>  		module_put(THIS_MODULE);
> 
> @@ -44,9 +46,10 @@ static void vfio_mdev_release(void *device_data)  {
>  	struct mdev_device *mdev = device_data;
>  	struct mdev_parent *parent = mdev->parent;
> +	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
> 
> -	if (likely(parent->ops->release))
> -		parent->ops->release(mdev);
> +	if (likely(ops->release))
> +		ops->release(mdev);
> 
>  	module_put(THIS_MODULE);
>  }
> @@ -56,11 +59,12 @@ static long vfio_mdev_unlocked_ioctl(void
> *device_data,  {
>  	struct mdev_device *mdev = device_data;
>  	struct mdev_parent *parent = mdev->parent;
> +	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
> 
> -	if (unlikely(!parent->ops->ioctl))
> +	if (unlikely(!ops->ioctl))
>  		return -EINVAL;
> 
> -	return parent->ops->ioctl(mdev, cmd, arg);
> +	return ops->ioctl(mdev, cmd, arg);
>  }
> 
>  static ssize_t vfio_mdev_read(void *device_data, char __user *buf, @@ -68,11
> +72,12 @@ static ssize_t vfio_mdev_read(void *device_data, char __user *buf,
> {
>  	struct mdev_device *mdev = device_data;
>  	struct mdev_parent *parent = mdev->parent;
> +	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
> 
> -	if (unlikely(!parent->ops->read))
> +	if (unlikely(!ops->read))
>  		return -EINVAL;
> 
> -	return parent->ops->read(mdev, buf, count, ppos);
> +	return ops->read(mdev, buf, count, ppos);
>  }
> 
>  static ssize_t vfio_mdev_write(void *device_data, const char __user *buf, @@
> -80,22 +85,24 @@ static ssize_t vfio_mdev_write(void *device_data, const char
> __user *buf,  {
>  	struct mdev_device *mdev = device_data;
>  	struct mdev_parent *parent = mdev->parent;
> +	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
> 
> -	if (unlikely(!parent->ops->write))
> +	if (unlikely(!ops->write))
>  		return -EINVAL;
> 
> -	return parent->ops->write(mdev, buf, count, ppos);
> +	return ops->write(mdev, buf, count, ppos);
>  }
> 
>  static int vfio_mdev_mmap(void *device_data, struct vm_area_struct *vma)  {
>  	struct mdev_device *mdev = device_data;
>  	struct mdev_parent *parent = mdev->parent;
> +	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
> 
> -	if (unlikely(!parent->ops->mmap))
> +	if (unlikely(!ops->mmap))
>  		return -EINVAL;
> 
> -	return parent->ops->mmap(mdev, vma);
> +	return ops->mmap(mdev, vma);
>  }
> 
>  static const struct vfio_device_ops vfio_mdev_dev_ops = { diff --git
> a/include/linux/mdev.h b/include/linux/mdev.h index
> 3ebae310f599..fa167bcb81e1 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -48,30 +48,8 @@ struct device *mdev_get_iommu_device(struct device
> *dev);
>   *			@mdev: mdev_device device structure which is being
>   *			       destroyed
>   *			Returns integer: success (0) or error (< 0)
> - * @open:		Open mediated device.
> - *			@mdev: mediated device.
> - *			Returns integer: success (0) or error (< 0)
> - * @release:		release mediated device
> - *			@mdev: mediated device.
> - * @read:		Read emulation callback
> - *			@mdev: mediated device structure
> - *			@buf: read buffer
> - *			@count: number of bytes to read
> - *			@ppos: address.
> - *			Retuns number on bytes read on success or error.
> - * @write:		Write emulation callback
> - *			@mdev: mediated device structure
> - *			@buf: write buffer
> - *			@count: number of bytes to be written
> - *			@ppos: address.
> - *			Retuns number on bytes written on success or error.
> - * @ioctl:		IOCTL callback
> - *			@mdev: mediated device structure
> - *			@cmd: ioctl command
> - *			@arg: arguments to ioctl
> - * @mmap:		mmap callback
> - *			@mdev: mediated device structure
> - *			@vma: vma structure
> + * @device_ops:         Device specific emulation callback.
> + *
>   * Parent device that support mediated device should be registered with mdev
>   * module with mdev_parent_ops structure.
>   **/
> @@ -83,15 +61,7 @@ struct mdev_parent_ops {
> 
>  	int     (*create)(struct kobject *kobj, struct mdev_device *mdev);
>  	int     (*remove)(struct mdev_device *mdev);
> -	int     (*open)(struct mdev_device *mdev);
> -	void    (*release)(struct mdev_device *mdev);
> -	ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
> -			size_t count, loff_t *ppos);
> -	ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
> -			 size_t count, loff_t *ppos);
> -	long	(*ioctl)(struct mdev_device *mdev, unsigned int cmd,
> -			 unsigned long arg);
> -	int	(*mmap)(struct mdev_device *mdev, struct vm_area_struct
> *vma);
> +	const void *device_ops;
>  };
> 
>  /* interface for exporting mdev supported type attributes */ diff --git
> a/include/linux/vfio_mdev.h b/include/linux/vfio_mdev.h new file mode
> 100644 index 000000000000..0c1b34f98f5d
> --- /dev/null
> +++ b/include/linux/vfio_mdev.h
> @@ -0,0 +1,53 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * VFIO Mediated device definition
> + */
> +
> +#ifndef VFIO_MDEV_H
> +#define VFIO_MDEV_H
> +
> +#include <linux/types.h>
> +#include <linux/mdev.h>
> +
> +/**
> + * struct vfio_mdev_parent_ops - Structure to be registered for each
> + * parent device to register the device to vfio-mdev module.
> + *
> + * @open:		Open mediated device.
> + *			@mdev: mediated device.
> + *			Returns integer: success (0) or error (< 0)
> + * @release:		release mediated device
> + *			@mdev: mediated device.
> + * @read:		Read emulation callback
> + *			@mdev: mediated device structure
> + *			@buf: read buffer
> + *			@count: number of bytes to read
> + *			@ppos: address.
> + *			Retuns number on bytes read on success or error.
> + * @write:		Write emulation callback
> + *			@mdev: mediated device structure
> + *			@buf: write buffer
> + *			@count: number of bytes to be written
> + *			@ppos: address.
> + *			Retuns number on bytes written on success or error.
> + * @ioctl:		IOCTL callback
> + *			@mdev: mediated device structure
> + *			@cmd: ioctl command
> + *			@arg: arguments to ioctl
> + * @mmap:		mmap callback
> + *			@mdev: mediated device structure
> + *			@vma: vma structure
> + */
> +struct vfio_mdev_parent_ops {
> +	int     (*open)(struct mdev_device *mdev);
> +	void    (*release)(struct mdev_device *mdev);
> +	ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
> +			size_t count, loff_t *ppos);
> +	ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
> +			 size_t count, loff_t *ppos);
> +	long	(*ioctl)(struct mdev_device *mdev, unsigned int cmd,
> +			 unsigned long arg);
> +	int	(*mmap)(struct mdev_device *mdev, struct vm_area_struct
> *vma);
> +};
> +
> +#endif
> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c index
> 71a4469be85d..107cc30d0f45 100644
> --- a/samples/vfio-mdev/mbochs.c
> +++ b/samples/vfio-mdev/mbochs.c
> @@ -30,6 +30,7 @@
>  #include <linux/iommu.h>
>  #include <linux/sysfs.h>
>  #include <linux/mdev.h>
> +#include <linux/vfio_mdev.h>
>  #include <linux/pci.h>
>  #include <linux/dma-buf.h>
>  #include <linux/highmem.h>
> @@ -1418,12 +1419,7 @@ static struct attribute_group *mdev_type_groups[]
> = {
>  	NULL,
>  };
> 
> -static const struct mdev_parent_ops mdev_fops = {
> -	.owner			= THIS_MODULE,
> -	.mdev_attr_groups	= mdev_dev_groups,
> -	.supported_type_groups	= mdev_type_groups,
> -	.create			= mbochs_create,
> -	.remove			= mbochs_remove,
> +static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
>  	.open			= mbochs_open,
>  	.release		= mbochs_close,
>  	.read			= mbochs_read,
> @@ -1432,6 +1428,15 @@ static const struct mdev_parent_ops mdev_fops = {
>  	.mmap			= mbochs_mmap,
>  };
> 
> +static const struct mdev_parent_ops mdev_fops = {
> +	.owner			= THIS_MODULE,
> +	.mdev_attr_groups	= mdev_dev_groups,
> +	.supported_type_groups	= mdev_type_groups,
> +	.create			= mbochs_create,
> +	.remove			= mbochs_remove,
> +	.device_ops		= &vfio_mdev_ops,
> +};
> +
>  static const struct file_operations vd_fops = {
>  	.owner		= THIS_MODULE,
>  };
> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index
> d3029dd27d91..2cd2018a53f9 100644
> --- a/samples/vfio-mdev/mdpy.c
> +++ b/samples/vfio-mdev/mdpy.c
> @@ -26,6 +26,7 @@
>  #include <linux/iommu.h>
>  #include <linux/sysfs.h>
>  #include <linux/mdev.h>
> +#include <linux/vfio_mdev.h>
>  #include <linux/pci.h>
>  #include <drm/drm_fourcc.h>
>  #include "mdpy-defs.h"
> @@ -725,12 +726,7 @@ static struct attribute_group *mdev_type_groups[] = {
>  	NULL,
>  };
> 
> -static const struct mdev_parent_ops mdev_fops = {
> -	.owner			= THIS_MODULE,
> -	.mdev_attr_groups	= mdev_dev_groups,
> -	.supported_type_groups	= mdev_type_groups,
> -	.create			= mdpy_create,
> -	.remove			= mdpy_remove,
> +static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
>  	.open			= mdpy_open,
>  	.release		= mdpy_close,
>  	.read			= mdpy_read,
> @@ -739,6 +735,15 @@ static const struct mdev_parent_ops mdev_fops = {
>  	.mmap			= mdpy_mmap,
>  };
> 
> +static const struct mdev_parent_ops mdev_fops = {
> +	.owner			= THIS_MODULE,
> +	.mdev_attr_groups	= mdev_dev_groups,
> +	.supported_type_groups	= mdev_type_groups,
> +	.create			= mdpy_create,
> +	.remove			= mdpy_remove,
> +	.device_ops		= &vfio_mdev_ops,
> +};
> +
>  static const struct file_operations vd_fops = {
>  	.owner		= THIS_MODULE,
>  };
> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c index
> 744c88a6b22c..e427425b5daf 100644
> --- a/samples/vfio-mdev/mtty.c
> +++ b/samples/vfio-mdev/mtty.c
> @@ -27,6 +27,7 @@
>  #include <linux/ctype.h>
>  #include <linux/file.h>
>  #include <linux/mdev.h>
> +#include <linux/vfio_mdev.h>
>  #include <linux/pci.h>
>  #include <linux/serial.h>
>  #include <uapi/linux/serial_reg.h>
> @@ -1410,6 +1411,14 @@ static struct attribute_group *mdev_type_groups[]
> = {
>  	NULL,
>  };
> 
> +static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
> +	.open                   = mtty_open,
> +	.release                = mtty_close,
> +	.read                   = mtty_read,
> +	.write                  = mtty_write,
> +	.ioctl		        = mtty_ioctl,
> +};
> +
>  static const struct mdev_parent_ops mdev_fops = {
>  	.owner                  = THIS_MODULE,
>  	.dev_attr_groups        = mtty_dev_groups,
> @@ -1417,11 +1426,7 @@ static const struct mdev_parent_ops mdev_fops = {
>  	.supported_type_groups  = mdev_type_groups,
>  	.create                 = mtty_create,
>  	.remove			= mtty_remove,
> -	.open                   = mtty_open,
> -	.release                = mtty_close,
> -	.read                   = mtty_read,
> -	.write                  = mtty_write,
> -	.ioctl		        = mtty_ioctl,
> +	.device_ops             = &vfio_mdev_ops,
>  };
> 
>  static void mtty_device_release(struct device *dev)
> --
> 2.19.1

Re: [PATCH 1/6] mdev: class id support

[Jason Wang]

On 2019/9/24 上午12:05, Alex Williamson wrote:
> On Mon, 23 Sep 2019 21:03:26 +0800
> Jason Wang <jasowang@redhat.com> wrote:
>
>> 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

Re: [PATCH 1/6] mdev: class id support

[Jason Wang]

On 2019/9/24 上午4:58, Parav Pandit wrote:
> Hi Jason,
>
>> -----Original Message-----
>> From: Jason Wang <jasowang@redhat.com>
>> Sent: Monday, September 23, 2019 8:03 AM
>> To: kvm@vger.kernel.org; linux-s390@vger.kernel.org; linux-
>> kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; intel-
>> gfx@lists.freedesktop.org; intel-gvt-dev@lists.freedesktop.org;
>> kwankhede@nvidia.com; alex.williamson@redhat.com; mst@redhat.com;
>> tiwei.bie@intel.com
>> Cc: virtualization@lists.linux-foundation.org; netdev@vger.kernel.org;
>> cohuck@redhat.com; maxime.coquelin@redhat.com;
>> cunming.liang@intel.com; zhihong.wang@intel.com;
>> rob.miller@broadcom.com; xiao.w.wang@intel.com;
>> haotian.wang@sifive.com; zhenyuw@linux.intel.com; zhi.a.wang@intel.com;
>> jani.nikula@linux.intel.com; joonas.lahtinen@linux.intel.com;
>> rodrigo.vivi@intel.com; airlied@linux.ie; daniel@ffwll.ch;
>> farman@linux.ibm.com; pasic@linux.ibm.com; sebott@linux.ibm.com;
>> oberpar@linux.ibm.com; heiko.carstens@de.ibm.com; gor@linux.ibm.com;
>> borntraeger@de.ibm.com; akrowiak@linux.ibm.com; freude@linux.ibm.com;
>> lingshan.zhu@intel.com; Ido Shamay <idos@mellanox.com>;
>> eperezma@redhat.com; lulu@redhat.com; Parav Pandit
>> <parav@mellanox.com>; Jason Wang <jasowang@redhat.com>
>> Subject: [PATCH 1/6] mdev: class id support
>>
>> 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.
> No full stop at the end.


Will fix this.


>
>>        */
>>       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);
>>
> Unrelated change in this patch.


Yes, will fix.


>
>>  * 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);
>>
> Cover letter from Change-V2 says that it class_id changed from " use u16 instead u8 for class id"
> But it is still u8 here?


Right, let me fix it in v2.


>
>>  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.
>>   *
> It device id here, but in below its class_id. Please make them uniform.


Yes, will fix.


>>   * 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)
>>  {
> u16 class_id?


Yes it is.


>
>>  	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;
>>
>>  	if (!mdev_bus_compat_class) {
>>  		mdev_bus_compat_class =
>> class_compat_register("mdev_bus");
>> @@ -208,7 +212,13 @@ int mdev_register_device(struct device *dev, const
>> struct mdev_parent_ops *ops)
>>  		put_device(dev);
>>  	return ret;
>>  }
>> -EXPORT_SYMBOL(mdev_register_device);
>> +
>> +int mdev_register_vfio_device(struct device *dev,
>> +			      const struct mdev_parent_ops *ops) {
>> +	return mdev_register_device(dev, ops, MDEV_ID_VFIO); }
>> +EXPORT_SYMBOL(mdev_register_vfio_device);
>>
>>  /*
>>   * mdev_unregister_device : Unregister a parent device diff --git
>> a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c index
>> 0d3223aee20b..b70bbebc9dd3 100644
>> --- a/drivers/vfio/mdev/mdev_driver.c
>> +++ b/drivers/vfio/mdev/mdev_driver.c
>> @@ -69,8 +69,22 @@ static int mdev_remove(struct device *dev)
>>  	return 0;
>>  }
>>
>> +static int mdev_match(struct device *dev, struct device_driver *drv) {
>> +	unsigned int i;
>> +	struct mdev_device *mdev = to_mdev_device(dev);
>> +	struct mdev_driver *mdrv = to_mdev_driver(drv);
>> +	const struct mdev_class_id *ids = mdrv->id_table;
>> +
>> +	for (i = 0; ids[i].id; i++)
>> +		if (ids[i].id == mdev->parent->class_id)
>> +			return 1;
>> +	return 0;
>> +}
>> +
>>  struct bus_type mdev_bus_type = {
>>  	.name		= "mdev",
>> +	.match		= mdev_match,
>>  	.probe		= mdev_probe,
>>  	.remove		= mdev_remove,
>>  };
>> diff --git a/drivers/vfio/mdev/mdev_private.h
>> b/drivers/vfio/mdev/mdev_private.h
>> index 7d922950caaf..e58b07c866b1 100644
>> --- a/drivers/vfio/mdev/mdev_private.h
>> +++ b/drivers/vfio/mdev/mdev_private.h
>> @@ -22,6 +22,7 @@ struct mdev_parent {
>>  	struct list_head type_list;
>>  	/* Synchronize device creation/removal with parent unregistration */
>>  	struct rw_semaphore unreg_sem;
>> +	u8 class_id;
>>  };
>>
>>  struct mdev_device {
>> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
>> index 30964a4e0a28..fd2a4d9a3f26 100644
>> --- a/drivers/vfio/mdev/vfio_mdev.c
>> +++ b/drivers/vfio/mdev/vfio_mdev.c
>> @@ -120,10 +120,16 @@ static void vfio_mdev_remove(struct device *dev)
>>  	vfio_del_group_dev(dev);
>>  }
>>
>> +static struct mdev_class_id id_table[] = {
>> +	{ MDEV_ID_VFIO },
>> +	{ 0 },
>> +};
>> +
>>  static struct mdev_driver vfio_mdev_driver = {
>>  	.name	= "vfio_mdev",
>>  	.probe	= vfio_mdev_probe,
>>  	.remove	= vfio_mdev_remove,
>> +	.id_table = id_table,
>>  };
>>
>>  static int __init vfio_mdev_init(void)
>> diff --git a/include/linux/mdev.h b/include/linux/mdev.h index
>> 0ce30ca78db0..3ebae310f599 100644
>> --- a/include/linux/mdev.h
>> +++ b/include/linux/mdev.h
>> @@ -118,6 +118,7 @@ struct mdev_type_attribute mdev_type_attr_##_name
>> =		\
>>   * @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 {
>> @@ -125,6 +126,7 @@ struct mdev_driver {
>>  	int  (*probe)(struct device *dev);
>>  	void (*remove)(struct device *dev);
>>  	struct device_driver driver;
>> +	const struct mdev_class_id *id_table;
>>  };
>>
>>  #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
>> @@ -135,7 +137,8 @@ const guid_t *mdev_uuid(struct mdev_device *mdev);
>>
>>  extern struct bus_type mdev_bus_type;
>>
>> -int mdev_register_device(struct device *dev, const struct mdev_parent_ops
>> *ops);
>> +int mdev_register_vfio_device(struct device *dev,
>> +			      const struct mdev_parent_ops *ops);
>>  void mdev_unregister_device(struct device *dev);
>>
>>  int mdev_register_driver(struct mdev_driver *drv, struct module *owner);
>> @@ -145,4 +148,6 @@ struct device *mdev_parent_dev(struct mdev_device
>> *mdev);  struct device *mdev_dev(struct mdev_device *mdev);  struct
>> mdev_device *mdev_from_dev(struct device *dev);
>>
>> +#define MDEV_ID_VFIO 1 /* VFIO device */
>> +
> Instead of define, please put them as enum 
>
> enum mdev_class/device_id {
> 	MDEV_ID_VFIO = 1,
> 	/* New entries must be added here */
> };


Ok.


>
>>  #endif /* MDEV_H */
>> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
>> index 5714fd35a83c..f32c6e44fb1a 100644
>> --- a/include/linux/mod_devicetable.h
>> +++ b/include/linux/mod_devicetable.h
>> @@ -821,4 +821,12 @@ struct wmi_device_id {
>>  	const void *context;
>>  };
>>
>> +/**
>> + * struct mdev_class_id - MDEV device class identifier
>> + * @id: Used to identify a specific class of device, e.g vfio-mdev device.
>> + */
>> +struct mdev_class_id {
>> +	__u16 id;
>> +};
> This is u16 as I guess you wanted as opposed to u8 in other places in patch.


Right.

Thanks


>> +
>>  #endif /* LINUX_MOD_DEVICETABLE_H */
>> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c index
>> ac5c8c17b1ff..71a4469be85d 100644
>> --- a/samples/vfio-mdev/mbochs.c
>> +++ b/samples/vfio-mdev/mbochs.c
>> @@ -1468,7 +1468,7 @@ static int __init mbochs_dev_init(void)
>>  	if (ret)
>>  		goto failed2;
>>
>> -	ret = mdev_register_device(&mbochs_dev, &mdev_fops);
>> +	ret = mdev_register_vfio_device(&mbochs_dev, &mdev_fops);
>>  	if (ret)
>>  		goto failed3;
>>
>> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index
>> cc86bf6566e4..d3029dd27d91 100644
>> --- a/samples/vfio-mdev/mdpy.c
>> +++ b/samples/vfio-mdev/mdpy.c
>> @@ -775,7 +775,7 @@ static int __init mdpy_dev_init(void)
>>  	if (ret)
>>  		goto failed2;
>>
>> -	ret = mdev_register_device(&mdpy_dev, &mdev_fops);
>> +	ret = mdev_register_vfio_device(&mdpy_dev, &mdev_fops);
>>  	if (ret)
>>  		goto failed3;
>>
>> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c index
>> 92e770a06ea2..744c88a6b22c 100644
>> --- a/samples/vfio-mdev/mtty.c
>> +++ b/samples/vfio-mdev/mtty.c
>> @@ -1468,7 +1468,7 @@ static int __init mtty_dev_init(void)
>>  	if (ret)
>>  		goto failed2;
>>
>> -	ret = mdev_register_device(&mtty_dev.dev, &mdev_fops);
>> +	ret = mdev_register_vfio_device(&mtty_dev.dev, &mdev_fops);
>>  	if (ret)
>>  		goto failed3;
>>
>> --
>> 2.19.1

Re: [PATCH 1/6] mdev: class id support

[Jason Wang]

On 2019/9/24 上午5:02, Parav Pandit wrote:
> Hi Jason,
>
>
>> -----Original Message-----
>> From: Jason Wang <jasowang@redhat.com>
>> Sent: Monday, September 23, 2019 8:03 AM
>> To: kvm@vger.kernel.org; linux-s390@vger.kernel.org; linux-
>> kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; intel-
>> gfx@lists.freedesktop.org; intel-gvt-dev@lists.freedesktop.org;
>> kwankhede@nvidia.com; alex.williamson@redhat.com; mst@redhat.com;
>> tiwei.bie@intel.com
>> Cc: virtualization@lists.linux-foundation.org; netdev@vger.kernel.org;
>> cohuck@redhat.com; maxime.coquelin@redhat.com;
>> cunming.liang@intel.com; zhihong.wang@intel.com;
>> rob.miller@broadcom.com; xiao.w.wang@intel.com;
>> haotian.wang@sifive.com; zhenyuw@linux.intel.com; zhi.a.wang@intel.com;
>> jani.nikula@linux.intel.com; joonas.lahtinen@linux.intel.com;
>> rodrigo.vivi@intel.com; airlied@linux.ie; daniel@ffwll.ch;
>> farman@linux.ibm.com; pasic@linux.ibm.com; sebott@linux.ibm.com;
>> oberpar@linux.ibm.com; heiko.carstens@de.ibm.com; gor@linux.ibm.com;
>> borntraeger@de.ibm.com; akrowiak@linux.ibm.com; freude@linux.ibm.com;
>> lingshan.zhu@intel.com; Ido Shamay <idos@mellanox.com>;
>> eperezma@redhat.com; lulu@redhat.com; Parav Pandit
>> <parav@mellanox.com>; Jason Wang <jasowang@redhat.com>
>> Subject: [PATCH 1/6] mdev: class id support
>>
>> 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(-)
>>
> You additionally need modpost support for id table integration to modifo, modprobe and other tools.
> A small patch similar to this one [1] is needed.
> Please include in the series.
>
> [1] https://lore.kernel.org/patchwork/patch/1046991/


My understanding is this could be done on top and may require uevent
support for the bus. I can try to implement this in V2.

Thanks

>
>

Re: [PATCH 2/6] mdev: introduce device specific ops

[Jason Wang]

On 2019/9/23 下午11:36, Michael S. Tsirkin wrote:
> On Mon, Sep 23, 2019 at 11:20:12PM +0800, kbuild test robot wrote:
>> Hi Jason,
>>
>> I love your patch! Yet something to improve:
>>
>> [auto build test ERROR on linus/master]
>> [cannot apply to v5.3 next-20190920]
>> [if your patch is applied to the wrong git tree, please drop us a note to help
>> improve the system. BTW, we also suggest to use '--base' option to specify the
>> base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
>>
>> url:    https://github.com/0day-ci/linux/commits/Jason-Wang/mdev-based-hardware-virtio-offloading-support/20190923-210738
>> config: ia64-allmodconfig (attached as .config)
>> compiler: ia64-linux-gcc (GCC) 7.4.0
>> reproduce:
>>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>>         chmod +x ~/bin/make.cross
>>         # save the attached .config to linux build tree
>>         GCC_VERSION=7.4.0 make.cross ARCH=ia64 
>>
>> If you fix the issue, kindly add following tag
>> Reported-by: kbuild test robot <lkp@intel.com>
>>
>> All error/warnings (new ones prefixed by >>):
> Looks like a bunch of includes missing. I guess they happen to
> be pulled in on some platforms but not others - ideally
> headers should be self contained though, pulling in
> all their dependencies.


Right, will fix in V2.

Thanks


>
>
>>    In file included from include/linux/vfio_mdev.h:10:0,
>>                     from <command-line>:0:
>>>> include/linux/mdev.h:25:34: warning: 'struct device' declared inside parameter list will not be visible outside of this definition or declaration
>>     int mdev_set_iommu_device(struct device *dev, struct device *iommu_device);
>>                                      ^~~~~~
>>>> include/linux/mdev.h:62:27: warning: 'struct kobject' declared inside parameter list will not be visible outside of this definition or declaration
>>      int     (*create)(struct kobject *kobj, struct mdev_device *mdev);
>>                               ^~~~~~~
>>>> include/linux/mdev.h:69:19: error: field 'attr' has incomplete type
>>      struct attribute attr;
>>                       ^~~~
>>    include/linux/mdev.h:70:25: warning: 'struct kobject' declared inside parameter list will not be visible outside of this definition or declaration
>>      ssize_t (*show)(struct kobject *kobj, struct device *dev, char *buf);
>>                             ^~~~~~~
>>    include/linux/mdev.h:71:26: warning: 'struct kobject' declared inside parameter list will not be visible outside of this definition or declaration
>>      ssize_t (*store)(struct kobject *kobj, struct device *dev,
>>                              ^~~~~~~
>>>> include/linux/mdev.h:98:23: error: field 'driver' has incomplete type
>>      struct device_driver driver;
>>                           ^~~~~~
>>>> include/linux/mdev.h:106:7: error: unknown type name 'guid_t'
>>     const guid_t *mdev_uuid(struct mdev_device *mdev);
>>           ^~~~~~
>>    In file included from <command-line>:0:0:
>>>> include/linux/vfio_mdev.h:50:47: warning: 'struct vm_area_struct' declared inside parameter list will not be visible outside of this definition or declaration
>>      int (*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
>>                                                   ^~~~~~~~~~~~~~
>>
>> vim +/attr +69 include/linux/mdev.h
>>
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   14  
>> 8ac13175cbe985 Lu Baolu        2019-04-12   15  /*
>> 8ac13175cbe985 Lu Baolu        2019-04-12   16   * Called by the parent device driver to set the device which represents
>> 8ac13175cbe985 Lu Baolu        2019-04-12   17   * this mdev in iommu protection scope. By default, the iommu device is
>> 8ac13175cbe985 Lu Baolu        2019-04-12   18   * NULL, that indicates using vendor defined isolation.
>> 8ac13175cbe985 Lu Baolu        2019-04-12   19   *
>> 8ac13175cbe985 Lu Baolu        2019-04-12   20   * @dev: the mediated device that iommu will isolate.
>> 8ac13175cbe985 Lu Baolu        2019-04-12   21   * @iommu_device: a pci device which represents the iommu for @dev.
>> 8ac13175cbe985 Lu Baolu        2019-04-12   22   *
>> 8ac13175cbe985 Lu Baolu        2019-04-12   23   * Return 0 for success, otherwise negative error value.
>> 8ac13175cbe985 Lu Baolu        2019-04-12   24   */
>> 8ac13175cbe985 Lu Baolu        2019-04-12  @25  int mdev_set_iommu_device(struct device *dev, struct device *iommu_device);
>> 8ac13175cbe985 Lu Baolu        2019-04-12   26  
>> 8ac13175cbe985 Lu Baolu        2019-04-12   27  struct device *mdev_get_iommu_device(struct device *dev);
>> 8ac13175cbe985 Lu Baolu        2019-04-12   28  
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   29  /**
>> 42930553a7c11f Alex Williamson 2016-12-30   30   * struct mdev_parent_ops - Structure to be registered for each parent device to
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   31   * register the device to mdev module.
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   32   *
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   33   * @owner:		The module owner.
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   34   * @dev_attr_groups:	Attributes of the parent device.
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   35   * @mdev_attr_groups:	Attributes of the mediated device.
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   36   * @supported_type_groups: Attributes to define supported types. It is mandatory
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   37   *			to provide supported types.
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   38   * @create:		Called to allocate basic resources in parent device's
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   39   *			driver for a particular mediated device. It is
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   40   *			mandatory to provide create ops.
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   41   *			@kobj: kobject of type for which 'create' is called.
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   42   *			@mdev: mdev_device structure on of mediated device
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   43   *			      that is being created
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   44   *			Returns integer: success (0) or error (< 0)
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   45   * @remove:		Called to free resources in parent device's driver for a
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   46   *			a mediated device. It is mandatory to provide 'remove'
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   47   *			ops.
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   48   *			@mdev: mdev_device device structure which is being
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   49   *			       destroyed
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   50   *			Returns integer: success (0) or error (< 0)
>> 0baad8a6f6fefa Jason Wang      2019-09-23   51   * @device_ops:         Device specific emulation callback.
>> 0baad8a6f6fefa Jason Wang      2019-09-23   52   *
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   53   * Parent device that support mediated device should be registered with mdev
>> 42930553a7c11f Alex Williamson 2016-12-30   54   * module with mdev_parent_ops structure.
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   55   **/
>> 42930553a7c11f Alex Williamson 2016-12-30   56  struct mdev_parent_ops {
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   57  	struct module   *owner;
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   58  	const struct attribute_group **dev_attr_groups;
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   59  	const struct attribute_group **mdev_attr_groups;
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   60  	struct attribute_group **supported_type_groups;
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   61  
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17  @62  	int     (*create)(struct kobject *kobj, struct mdev_device *mdev);
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   63  	int     (*remove)(struct mdev_device *mdev);
>> 0baad8a6f6fefa Jason Wang      2019-09-23   64  	const void *device_ops;
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   65  };
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   66  
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   67  /* interface for exporting mdev supported type attributes */
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   68  struct mdev_type_attribute {
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17  @69  	struct attribute attr;
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17  @70  	ssize_t (*show)(struct kobject *kobj, struct device *dev, char *buf);
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   71  	ssize_t (*store)(struct kobject *kobj, struct device *dev,
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   72  			 const char *buf, size_t count);
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   73  };
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   74  
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   75  #define MDEV_TYPE_ATTR(_name, _mode, _show, _store)		\
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   76  struct mdev_type_attribute mdev_type_attr_##_name =		\
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   77  	__ATTR(_name, _mode, _show, _store)
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   78  #define MDEV_TYPE_ATTR_RW(_name) \
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   79  	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RW(_name)
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   80  #define MDEV_TYPE_ATTR_RO(_name) \
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   81  	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RO(_name)
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   82  #define MDEV_TYPE_ATTR_WO(_name) \
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   83  	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_WO(_name)
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   84  
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   85  /**
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   86   * struct mdev_driver - Mediated device driver
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   87   * @name: driver name
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   88   * @probe: called when new device created
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   89   * @remove: called when device removed
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   90   * @driver: device driver structure
>> 6294ee8e0b5153 Jason Wang      2019-09-23   91   * @id_table: the ids serviced by this driver.
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   92   *
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   93   **/
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   94  struct mdev_driver {
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   95  	const char *name;
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   96  	int  (*probe)(struct device *dev);
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17   97  	void (*remove)(struct device *dev);
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17  @98  	struct device_driver driver;
>> 6294ee8e0b5153 Jason Wang      2019-09-23   99  	const struct mdev_class_id *id_table;
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17  100  };
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17  101  
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17  102  #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17  103  
>> 50732af3b65691 Parav Pandit    2019-04-30  104  void *mdev_get_drvdata(struct mdev_device *mdev);
>> 50732af3b65691 Parav Pandit    2019-04-30  105  void mdev_set_drvdata(struct mdev_device *mdev, void *data);
>> 50732af3b65691 Parav Pandit    2019-04-30 @106  const guid_t *mdev_uuid(struct mdev_device *mdev);
>> 7b96953bc640b6 Kirti Wankhede  2016-11-17  107  
>>
>> :::::: The code at line 69 was first introduced by commit
>> :::::: 7b96953bc640b6b25665fe17ffca4b668b371f14 vfio: Mediated device Core driver
>>
>> :::::: TO: Kirti Wankhede <kwankhede@nvidia.com>
>> :::::: CC: Alex Williamson <alex.williamson@redhat.com>
>>
>> ---
>> 0-DAY kernel test infrastructure                Open Source Technology Center
>> https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
>

Re: [PATCH 2/6] mdev: introduce device specific ops

[Jason Wang]

On 2019/9/24 上午6:59, Parav Pandit wrote:
>
>> -----Original Message-----
>> From: Jason Wang <jasowang@redhat.com>
>> Sent: Monday, September 23, 2019 8:03 AM
>> To: kvm@vger.kernel.org; linux-s390@vger.kernel.org; linux-
>> kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; intel-
>> gfx@lists.freedesktop.org; intel-gvt-dev@lists.freedesktop.org;
>> kwankhede@nvidia.com; alex.williamson@redhat.com; mst@redhat.com;
>> tiwei.bie@intel.com
>> Cc: virtualization@lists.linux-foundation.org; netdev@vger.kernel.org;
>> cohuck@redhat.com; maxime.coquelin@redhat.com;
>> cunming.liang@intel.com; zhihong.wang@intel.com;
>> rob.miller@broadcom.com; xiao.w.wang@intel.com;
>> haotian.wang@sifive.com; zhenyuw@linux.intel.com; zhi.a.wang@intel.com;
>> jani.nikula@linux.intel.com; joonas.lahtinen@linux.intel.com;
>> rodrigo.vivi@intel.com; airlied@linux.ie; daniel@ffwll.ch;
>> farman@linux.ibm.com; pasic@linux.ibm.com; sebott@linux.ibm.com;
>> oberpar@linux.ibm.com; heiko.carstens@de.ibm.com; gor@linux.ibm.com;
>> borntraeger@de.ibm.com; akrowiak@linux.ibm.com; freude@linux.ibm.com;
>> lingshan.zhu@intel.com; Ido Shamay <idos@mellanox.com>;
>> eperezma@redhat.com; lulu@redhat.com; Parav Pandit
>> <parav@mellanox.com>; Jason Wang <jasowang@redhat.com>
>> Subject: [PATCH 2/6] mdev: introduce device specific ops
>>
>> Currently, except for the create and remove. The rest of mdev_parent_ops is
>> designed for vfio-mdev driver only and may not help for kernel mdev driver.
>> Follow the class id support by previous patch, this patch introduces device
>> specific ops pointer inside parent ops which points to device specific ops (e.g
>> vfio ops). This allows the future drivers like virtio-mdev to implement its own
>> device specific ops.
>>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>  .../driver-api/vfio-mediated-device.rst       |  4 +-
>>  MAINTAINERS                                   |  1 +
>>  drivers/gpu/drm/i915/gvt/kvmgt.c              | 15 +++---
>>  drivers/s390/cio/vfio_ccw_ops.c               | 15 ++++--
>>  drivers/s390/crypto/vfio_ap_ops.c             | 11 ++--
>>  drivers/vfio/mdev/vfio_mdev.c                 | 31 ++++++-----
>>  include/linux/mdev.h                          | 36 ++-----------
>>  include/linux/vfio_mdev.h                     | 53 +++++++++++++++++++
>>  samples/vfio-mdev/mbochs.c                    | 17 +++---
>>  samples/vfio-mdev/mdpy.c                      | 17 +++---
>>  samples/vfio-mdev/mtty.c                      | 15 ++++--
>>  11 files changed, 138 insertions(+), 77 deletions(-)  create mode 100644
>> include/linux/vfio_mdev.h
>>
>> diff --git a/Documentation/driver-api/vfio-mediated-device.rst
>> b/Documentation/driver-api/vfio-mediated-device.rst
>> index 0e052072e1d8..3ab00e48212f 100644
>> --- a/Documentation/driver-api/vfio-mediated-device.rst
>> +++ b/Documentation/driver-api/vfio-mediated-device.rst
>> @@ -152,7 +152,9 @@ callbacks per mdev parent device, per mdev type, or
>> any other categorization.
>>  Vendor drivers are expected to be fully asynchronous in this respect or
>> provide their own internal resource protection.)
>>
>> -The callbacks in the mdev_parent_ops structure are as follows:
>> +The device specific callbacks are referred through device_ops pointer
>> +in mdev_parent_ops. For vfio-mdev device, its callbacks in device_ops
>> +are as follows:
>>
>>  * open: open callback of mediated device
>>  * close: close callback of mediated device diff --git a/MAINTAINERS
>> b/MAINTAINERS index b2326dece28e..89832b316500 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -17075,6 +17075,7 @@ S:	Maintained
>>  F:	Documentation/driver-api/vfio-mediated-device.rst
>>  F:	drivers/vfio/mdev/
>>  F:	include/linux/mdev.h
>> +F:	include/linux/vfio_mdev.h
>>  F:	samples/vfio-mdev/
>>
>>  VFIO PLATFORM DRIVER
>> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c
>> b/drivers/gpu/drm/i915/gvt/kvmgt.c
>> index 19d51a35f019..8ea86b1e69f1 100644
>> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
>> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
>> @@ -42,6 +42,7 @@
>>  #include <linux/kvm_host.h>
>>  #include <linux/vfio.h>
>>  #include <linux/mdev.h>
>> +#include <linux/vfio_mdev.h>
>>  #include <linux/debugfs.h>
>>
>>  #include <linux/nospec.h>
>> @@ -1600,20 +1601,22 @@ static const struct attribute_group
>> *intel_vgpu_groups[] = {
>>  	NULL,
>>  };
>>
>> -static struct mdev_parent_ops intel_vgpu_ops = {
>> -	.mdev_attr_groups       = intel_vgpu_groups,
>> -	.create			= intel_vgpu_create,
>> -	.remove			= intel_vgpu_remove,
>> -
>> +static struct vfio_mdev_parent_ops intel_vfio_vgpu_ops = {
> Naming it with _dev prefix as intel_vfio_vgpu_dev_ops is better to differentiate with parent_ops.


Ok.


>>  	.open			= intel_vgpu_open,
>>  	.release		= intel_vgpu_release,
>> -
>>  	.read			= intel_vgpu_read,
>>  	.write			= intel_vgpu_write,
>>  	.mmap			= intel_vgpu_mmap,
>>  	.ioctl			= intel_vgpu_ioctl,
>>  };
>>
>> +static struct mdev_parent_ops intel_vgpu_ops = {
>> +	.mdev_attr_groups       = intel_vgpu_groups,
>> +	.create			= intel_vgpu_create,
>> +	.remove			= intel_vgpu_remove,
>> +	.device_ops	        = &intel_vfio_vgpu_ops,
>> +};
>> +
>>  static int kvmgt_host_init(struct device *dev, void *gvt, const void *ops)  {
>>  	struct attribute **kvm_type_attrs;
>> diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
>> index 246ff0f80944..02122bbc213e 100644
>> --- a/drivers/s390/cio/vfio_ccw_ops.c
>> +++ b/drivers/s390/cio/vfio_ccw_ops.c
>> @@ -12,6 +12,7 @@
>>
>>  #include <linux/vfio.h>
>>  #include <linux/mdev.h>
>> +#include <linux/vfio_mdev.h>
>>  #include <linux/nospec.h>
>>  #include <linux/slab.h>
>>
>> @@ -574,11 +575,7 @@ static ssize_t vfio_ccw_mdev_ioctl(struct
>> mdev_device *mdev,
>>  	}
>>  }
>>
>> -static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
>> -	.owner			= THIS_MODULE,
>> -	.supported_type_groups  = mdev_type_groups,
>> -	.create			= vfio_ccw_mdev_create,
>> -	.remove			= vfio_ccw_mdev_remove,
>> +static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
>>  	.open			= vfio_ccw_mdev_open,
>>  	.release		= vfio_ccw_mdev_release,
>>  	.read			= vfio_ccw_mdev_read,
>> @@ -586,6 +583,14 @@ static const struct mdev_parent_ops
>> vfio_ccw_mdev_ops = {
>>  	.ioctl			= vfio_ccw_mdev_ioctl,
>>  };
>>
>> +static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
>> +	.owner			= THIS_MODULE,
>> +	.supported_type_groups  = mdev_type_groups,
>> +	.create			= vfio_ccw_mdev_create,
>> +	.remove			= vfio_ccw_mdev_remove,
>> +	.device_ops		= &vfio_mdev_ops,
>> +};
>> +
>>  int vfio_ccw_mdev_reg(struct subchannel *sch)  {
>>  	return mdev_register_vfio_device(&sch->dev, &vfio_ccw_mdev_ops);
>> diff --git a/drivers/s390/crypto/vfio_ap_ops.c
>> b/drivers/s390/crypto/vfio_ap_ops.c
>> index 7487fc39d2c5..4251becc7a6d 100644
>> --- a/drivers/s390/crypto/vfio_ap_ops.c
>> +++ b/drivers/s390/crypto/vfio_ap_ops.c
>> @@ -16,6 +16,7 @@
>>  #include <linux/bitops.h>
>>  #include <linux/kvm_host.h>
>>  #include <linux/module.h>
>> +#include <linux/vfio_mdev.h>
>>  #include <asm/kvm.h>
>>  #include <asm/zcrypt.h>
>>
>> @@ -1280,15 +1281,19 @@ static ssize_t vfio_ap_mdev_ioctl(struct
>> mdev_device *mdev,
>>  	return ret;
>>  }
>>
>> +static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
>> +	.open			= vfio_ap_mdev_open,
>> +	.release		= vfio_ap_mdev_release,
>> +	.ioctl			= vfio_ap_mdev_ioctl,
>> +};
>> +
>>  static const struct mdev_parent_ops vfio_ap_matrix_ops = {
>>  	.owner			= THIS_MODULE,
>>  	.supported_type_groups	= vfio_ap_mdev_type_groups,
>>  	.mdev_attr_groups	= vfio_ap_mdev_attr_groups,
>>  	.create			= vfio_ap_mdev_create,
>>  	.remove			= vfio_ap_mdev_remove,
>> -	.open			= vfio_ap_mdev_open,
>> -	.release		= vfio_ap_mdev_release,
>> -	.ioctl			= vfio_ap_mdev_ioctl,
>> +	.device_ops		= &vfio_mdev_ops,
>>  };
>>
>>  int vfio_ap_mdev_register(void)
>> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
>> index fd2a4d9a3f26..d23c9f58c84f 100644
>> --- a/drivers/vfio/mdev/vfio_mdev.c
>> +++ b/drivers/vfio/mdev/vfio_mdev.c
>> @@ -14,6 +14,7 @@
>>  #include <linux/slab.h>
>>  #include <linux/vfio.h>
>>  #include <linux/mdev.h>
>> +#include <linux/vfio_mdev.h>
>>
>>  #include "mdev_private.h"
>>
>> @@ -25,15 +26,16 @@ static int vfio_mdev_open(void *device_data)  {
>>  	struct mdev_device *mdev = device_data;
>>  	struct mdev_parent *parent = mdev->parent;
>> +	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
>>  	int ret;
>>
>> -	if (unlikely(!parent->ops->open))
>> +	if (unlikely(!ops->open))
>>  		return -EINVAL;
>>
> device_ops is optional and can be NULL for mdev devices which are not required to be mapped via vfio.
> So please change to,
>
> If (!ops || !ops->open)
> 	return -EINVAL;
>
> and rest of the below places.


My understanding is vfio_mdev can not talk to non vfio mdev device with
the help of class id.

Thanks


>
>>  	if (!try_module_get(THIS_MODULE))
>>  		return -ENODEV;
>>
>> -	ret = parent->ops->open(mdev);
>> +	ret = ops->open(mdev);
>>  	if (ret)
>>  		module_put(THIS_MODULE);
>>
>> @@ -44,9 +46,10 @@ static void vfio_mdev_release(void *device_data)  {
>>  	struct mdev_device *mdev = device_data;
>>  	struct mdev_parent *parent = mdev->parent;
>> +	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
>>
>> -	if (likely(parent->ops->release))
>> -		parent->ops->release(mdev);
>> +	if (likely(ops->release))
>> +		ops->release(mdev);
>>
>>  	module_put(THIS_MODULE);
>>  }
>> @@ -56,11 +59,12 @@ static long vfio_mdev_unlocked_ioctl(void
>> *device_data,  {
>>  	struct mdev_device *mdev = device_data;
>>  	struct mdev_parent *parent = mdev->parent;
>> +	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
>>
>> -	if (unlikely(!parent->ops->ioctl))
>> +	if (unlikely(!ops->ioctl))
>>  		return -EINVAL;
>>
>> -	return parent->ops->ioctl(mdev, cmd, arg);
>> +	return ops->ioctl(mdev, cmd, arg);
>>  }
>>
>>  static ssize_t vfio_mdev_read(void *device_data, char __user *buf, @@ -68,11
>> +72,12 @@ static ssize_t vfio_mdev_read(void *device_data, char __user *buf,
>> {
>>  	struct mdev_device *mdev = device_data;
>>  	struct mdev_parent *parent = mdev->parent;
>> +	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
>>
>> -	if (unlikely(!parent->ops->read))
>> +	if (unlikely(!ops->read))
>>  		return -EINVAL;
>>
>> -	return parent->ops->read(mdev, buf, count, ppos);
>> +	return ops->read(mdev, buf, count, ppos);
>>  }
>>
>>  static ssize_t vfio_mdev_write(void *device_data, const char __user *buf, @@
>> -80,22 +85,24 @@ static ssize_t vfio_mdev_write(void *device_data, const char
>> __user *buf,  {
>>  	struct mdev_device *mdev = device_data;
>>  	struct mdev_parent *parent = mdev->parent;
>> +	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
>>
>> -	if (unlikely(!parent->ops->write))
>> +	if (unlikely(!ops->write))
>>  		return -EINVAL;
>>
>> -	return parent->ops->write(mdev, buf, count, ppos);
>> +	return ops->write(mdev, buf, count, ppos);
>>  }
>>
>>  static int vfio_mdev_mmap(void *device_data, struct vm_area_struct *vma)  {
>>  	struct mdev_device *mdev = device_data;
>>  	struct mdev_parent *parent = mdev->parent;
>> +	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
>>
>> -	if (unlikely(!parent->ops->mmap))
>> +	if (unlikely(!ops->mmap))
>>  		return -EINVAL;
>>
>> -	return parent->ops->mmap(mdev, vma);
>> +	return ops->mmap(mdev, vma);
>>  }
>>
>>  static const struct vfio_device_ops vfio_mdev_dev_ops = { diff --git
>> a/include/linux/mdev.h b/include/linux/mdev.h index
>> 3ebae310f599..fa167bcb81e1 100644
>> --- a/include/linux/mdev.h
>> +++ b/include/linux/mdev.h
>> @@ -48,30 +48,8 @@ struct device *mdev_get_iommu_device(struct device
>> *dev);
>>   *			@mdev: mdev_device device structure which is being
>>   *			       destroyed
>>   *			Returns integer: success (0) or error (< 0)
>> - * @open:		Open mediated device.
>> - *			@mdev: mediated device.
>> - *			Returns integer: success (0) or error (< 0)
>> - * @release:		release mediated device
>> - *			@mdev: mediated device.
>> - * @read:		Read emulation callback
>> - *			@mdev: mediated device structure
>> - *			@buf: read buffer
>> - *			@count: number of bytes to read
>> - *			@ppos: address.
>> - *			Retuns number on bytes read on success or error.
>> - * @write:		Write emulation callback
>> - *			@mdev: mediated device structure
>> - *			@buf: write buffer
>> - *			@count: number of bytes to be written
>> - *			@ppos: address.
>> - *			Retuns number on bytes written on success or error.
>> - * @ioctl:		IOCTL callback
>> - *			@mdev: mediated device structure
>> - *			@cmd: ioctl command
>> - *			@arg: arguments to ioctl
>> - * @mmap:		mmap callback
>> - *			@mdev: mediated device structure
>> - *			@vma: vma structure
>> + * @device_ops:         Device specific emulation callback.
>> + *
>>   * Parent device that support mediated device should be registered with mdev
>>   * module with mdev_parent_ops structure.
>>   **/
>> @@ -83,15 +61,7 @@ struct mdev_parent_ops {
>>
>>  	int     (*create)(struct kobject *kobj, struct mdev_device *mdev);
>>  	int     (*remove)(struct mdev_device *mdev);
>> -	int     (*open)(struct mdev_device *mdev);
>> -	void    (*release)(struct mdev_device *mdev);
>> -	ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
>> -			size_t count, loff_t *ppos);
>> -	ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
>> -			 size_t count, loff_t *ppos);
>> -	long	(*ioctl)(struct mdev_device *mdev, unsigned int cmd,
>> -			 unsigned long arg);
>> -	int	(*mmap)(struct mdev_device *mdev, struct vm_area_struct
>> *vma);
>> +	const void *device_ops;
>>  };
>>
>>  /* interface for exporting mdev supported type attributes */ diff --git
>> a/include/linux/vfio_mdev.h b/include/linux/vfio_mdev.h new file mode
>> 100644 index 000000000000..0c1b34f98f5d
>> --- /dev/null
>> +++ b/include/linux/vfio_mdev.h
>> @@ -0,0 +1,53 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +/*
>> + * VFIO Mediated device definition
>> + */
>> +
>> +#ifndef VFIO_MDEV_H
>> +#define VFIO_MDEV_H
>> +
>> +#include <linux/types.h>
>> +#include <linux/mdev.h>
>> +
>> +/**
>> + * struct vfio_mdev_parent_ops - Structure to be registered for each
>> + * parent device to register the device to vfio-mdev module.
>> + *
>> + * @open:		Open mediated device.
>> + *			@mdev: mediated device.
>> + *			Returns integer: success (0) or error (< 0)
>> + * @release:		release mediated device
>> + *			@mdev: mediated device.
>> + * @read:		Read emulation callback
>> + *			@mdev: mediated device structure
>> + *			@buf: read buffer
>> + *			@count: number of bytes to read
>> + *			@ppos: address.
>> + *			Retuns number on bytes read on success or error.
>> + * @write:		Write emulation callback
>> + *			@mdev: mediated device structure
>> + *			@buf: write buffer
>> + *			@count: number of bytes to be written
>> + *			@ppos: address.
>> + *			Retuns number on bytes written on success or error.
>> + * @ioctl:		IOCTL callback
>> + *			@mdev: mediated device structure
>> + *			@cmd: ioctl command
>> + *			@arg: arguments to ioctl
>> + * @mmap:		mmap callback
>> + *			@mdev: mediated device structure
>> + *			@vma: vma structure
>> + */
>> +struct vfio_mdev_parent_ops {
>> +	int     (*open)(struct mdev_device *mdev);
>> +	void    (*release)(struct mdev_device *mdev);
>> +	ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
>> +			size_t count, loff_t *ppos);
>> +	ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
>> +			 size_t count, loff_t *ppos);
>> +	long	(*ioctl)(struct mdev_device *mdev, unsigned int cmd,
>> +			 unsigned long arg);
>> +	int	(*mmap)(struct mdev_device *mdev, struct vm_area_struct
>> *vma);
>> +};
>> +
>> +#endif
>> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c index
>> 71a4469be85d..107cc30d0f45 100644
>> --- a/samples/vfio-mdev/mbochs.c
>> +++ b/samples/vfio-mdev/mbochs.c
>> @@ -30,6 +30,7 @@
>>  #include <linux/iommu.h>
>>  #include <linux/sysfs.h>
>>  #include <linux/mdev.h>
>> +#include <linux/vfio_mdev.h>
>>  #include <linux/pci.h>
>>  #include <linux/dma-buf.h>
>>  #include <linux/highmem.h>
>> @@ -1418,12 +1419,7 @@ static struct attribute_group *mdev_type_groups[]
>> = {
>>  	NULL,
>>  };
>>
>> -static const struct mdev_parent_ops mdev_fops = {
>> -	.owner			= THIS_MODULE,
>> -	.mdev_attr_groups	= mdev_dev_groups,
>> -	.supported_type_groups	= mdev_type_groups,
>> -	.create			= mbochs_create,
>> -	.remove			= mbochs_remove,
>> +static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
>>  	.open			= mbochs_open,
>>  	.release		= mbochs_close,
>>  	.read			= mbochs_read,
>> @@ -1432,6 +1428,15 @@ static const struct mdev_parent_ops mdev_fops = {
>>  	.mmap			= mbochs_mmap,
>>  };
>>
>> +static const struct mdev_parent_ops mdev_fops = {
>> +	.owner			= THIS_MODULE,
>> +	.mdev_attr_groups	= mdev_dev_groups,
>> +	.supported_type_groups	= mdev_type_groups,
>> +	.create			= mbochs_create,
>> +	.remove			= mbochs_remove,
>> +	.device_ops		= &vfio_mdev_ops,
>> +};
>> +
>>  static const struct file_operations vd_fops = {
>>  	.owner		= THIS_MODULE,
>>  };
>> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index
>> d3029dd27d91..2cd2018a53f9 100644
>> --- a/samples/vfio-mdev/mdpy.c
>> +++ b/samples/vfio-mdev/mdpy.c
>> @@ -26,6 +26,7 @@
>>  #include <linux/iommu.h>
>>  #include <linux/sysfs.h>
>>  #include <linux/mdev.h>
>> +#include <linux/vfio_mdev.h>
>>  #include <linux/pci.h>
>>  #include <drm/drm_fourcc.h>
>>  #include "mdpy-defs.h"
>> @@ -725,12 +726,7 @@ static struct attribute_group *mdev_type_groups[] = {
>>  	NULL,
>>  };
>>
>> -static const struct mdev_parent_ops mdev_fops = {
>> -	.owner			= THIS_MODULE,
>> -	.mdev_attr_groups	= mdev_dev_groups,
>> -	.supported_type_groups	= mdev_type_groups,
>> -	.create			= mdpy_create,
>> -	.remove			= mdpy_remove,
>> +static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
>>  	.open			= mdpy_open,
>>  	.release		= mdpy_close,
>>  	.read			= mdpy_read,
>> @@ -739,6 +735,15 @@ static const struct mdev_parent_ops mdev_fops = {
>>  	.mmap			= mdpy_mmap,
>>  };
>>
>> +static const struct mdev_parent_ops mdev_fops = {
>> +	.owner			= THIS_MODULE,
>> +	.mdev_attr_groups	= mdev_dev_groups,
>> +	.supported_type_groups	= mdev_type_groups,
>> +	.create			= mdpy_create,
>> +	.remove			= mdpy_remove,
>> +	.device_ops		= &vfio_mdev_ops,
>> +};
>> +
>>  static const struct file_operations vd_fops = {
>>  	.owner		= THIS_MODULE,
>>  };
>> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c index
>> 744c88a6b22c..e427425b5daf 100644
>> --- a/samples/vfio-mdev/mtty.c
>> +++ b/samples/vfio-mdev/mtty.c
>> @@ -27,6 +27,7 @@
>>  #include <linux/ctype.h>
>>  #include <linux/file.h>
>>  #include <linux/mdev.h>
>> +#include <linux/vfio_mdev.h>
>>  #include <linux/pci.h>
>>  #include <linux/serial.h>
>>  #include <uapi/linux/serial_reg.h>
>> @@ -1410,6 +1411,14 @@ static struct attribute_group *mdev_type_groups[]
>> = {
>>  	NULL,
>>  };
>>
>> +static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
>> +	.open                   = mtty_open,
>> +	.release                = mtty_close,
>> +	.read                   = mtty_read,
>> +	.write                  = mtty_write,
>> +	.ioctl		        = mtty_ioctl,
>> +};
>> +
>>  static const struct mdev_parent_ops mdev_fops = {
>>  	.owner                  = THIS_MODULE,
>>  	.dev_attr_groups        = mtty_dev_groups,
>> @@ -1417,11 +1426,7 @@ static const struct mdev_parent_ops mdev_fops = {
>>  	.supported_type_groups  = mdev_type_groups,
>>  	.create                 = mtty_create,
>>  	.remove			= mtty_remove,
>> -	.open                   = mtty_open,
>> -	.release                = mtty_close,
>> -	.read                   = mtty_read,
>> -	.write                  = mtty_write,
>> -	.ioctl		        = mtty_ioctl,
>> +	.device_ops             = &vfio_mdev_ops,
>>  };
>>
>>  static void mtty_device_release(struct device *dev)
>> --
>> 2.19.1

Re: [PATCH 4/6] virtio: introduce a mdev based transport

[Jason Wang]

On 2019/9/24 上午6:28, Parav Pandit wrote:
>
>> -----Original Message-----
>> From: Jason Wang <jasowang@redhat.com>
>> Sent: Monday, September 23, 2019 8:03 AM
>> To: kvm@vger.kernel.org; linux-s390@vger.kernel.org; linux-
>> kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; intel-
>> gfx@lists.freedesktop.org; intel-gvt-dev@lists.freedesktop.org;
>> kwankhede@nvidia.com; alex.williamson@redhat.com; mst@redhat.com;
>> tiwei.bie@intel.com
>> Cc: virtualization@lists.linux-foundation.org; netdev@vger.kernel.org;
>> cohuck@redhat.com; maxime.coquelin@redhat.com;
>> cunming.liang@intel.com; zhihong.wang@intel.com;
>> rob.miller@broadcom.com; xiao.w.wang@intel.com;
>> haotian.wang@sifive.com; zhenyuw@linux.intel.com; zhi.a.wang@intel.com;
>> jani.nikula@linux.intel.com; joonas.lahtinen@linux.intel.com;
>> rodrigo.vivi@intel.com; airlied@linux.ie; daniel@ffwll.ch;
>> farman@linux.ibm.com; pasic@linux.ibm.com; sebott@linux.ibm.com;
>> oberpar@linux.ibm.com; heiko.carstens@de.ibm.com; gor@linux.ibm.com;
>> borntraeger@de.ibm.com; akrowiak@linux.ibm.com; freude@linux.ibm.com;
>> lingshan.zhu@intel.com; Ido Shamay <idos@mellanox.com>;
>> eperezma@redhat.com; lulu@redhat.com; Parav Pandit
>> <parav@mellanox.com>; Jason Wang <jasowang@redhat.com>
>> Subject: [PATCH 4/6] virtio: introduce a mdev based transport
>>
>> This patch introduces a new mdev transport for virtio. This is used to use kernel
>> virtio driver to drive the mediated device that is capable of populating
>> virtqueue directly.
>>
>> A new virtio-mdev driver will be registered to the mdev bus, when a new virtio-
>> mdev device is probed, it will register the device with mdev based config ops.
>> This means it is a software transport between mdev driver and mdev device.
>> The transport was implemented through device specific opswhich is a part of
>> mdev_parent_ops now.
>>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>  MAINTAINERS                     |   1 +
>>  drivers/vfio/mdev/Kconfig       |   7 +
>>  drivers/vfio/mdev/Makefile      |   1 +
>>  drivers/vfio/mdev/virtio_mdev.c | 416 ++++++++++++++++++++++++++++++++
>>  4 files changed, 425 insertions(+)
>>  create mode 100644 drivers/vfio/mdev/virtio_mdev.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 89832b316500..820ec250cc52 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -17202,6 +17202,7 @@ F:	include/linux/virtio*.h
>>  F:	include/uapi/linux/virtio_*.h
>>  F:	drivers/crypto/virtio/
>>  F:	mm/balloon_compaction.c
>> +F:	drivers/vfio/mdev/virtio_mdev.c
>>
>>  VIRTIO BLOCK AND SCSI DRIVERS
>>  M:	"Michael S. Tsirkin" <mst@redhat.com>
>> diff --git a/drivers/vfio/mdev/Kconfig b/drivers/vfio/mdev/Kconfig index
>> 5da27f2100f9..c488c31fc137 100644
>> --- a/drivers/vfio/mdev/Kconfig
>> +++ b/drivers/vfio/mdev/Kconfig
>> @@ -16,3 +16,10 @@ config VFIO_MDEV_DEVICE
>>  	default n
>>  	help
>>  	  VFIO based driver for Mediated devices.
>> +
>> +config VIRTIO_MDEV_DEVICE
>> +	tristate "VIRTIO driver for Mediated devices"
>> +	depends on VFIO_MDEV && VIRTIO
>> +	default n
>> +	help
>> +	  VIRTIO based driver for Mediated devices.
>> diff --git a/drivers/vfio/mdev/Makefile b/drivers/vfio/mdev/Makefile index
>> 101516fdf375..99d31e29c23e 100644
>> --- a/drivers/vfio/mdev/Makefile
>> +++ b/drivers/vfio/mdev/Makefile
>> @@ -4,3 +4,4 @@ mdev-y := mdev_core.o mdev_sysfs.o mdev_driver.o
>>
>>  obj-$(CONFIG_VFIO_MDEV) += mdev.o
>>  obj-$(CONFIG_VFIO_MDEV_DEVICE) += vfio_mdev.o
>> +obj-$(CONFIG_VIRTIO_MDEV_DEVICE) += virtio_mdev.o
>> diff --git a/drivers/vfio/mdev/virtio_mdev.c b/drivers/vfio/mdev/virtio_mdev.c
>> new file mode 100644 index 000000000000..919a082adc9c
>> --- /dev/null
>> +++ b/drivers/vfio/mdev/virtio_mdev.c
>> @@ -0,0 +1,416 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * VIRTIO based driver for Mediated device
>> + *
>> + * Copyright (c) 2019, Red Hat. All rights reserved.
>> + *     Author: Jason Wang <jasowang@redhat.com>
>> + *
>> + */
>> +
>> +#include <linux/init.h>
>> +#include <linux/module.h>
>> +#include <linux/device.h>
>> +#include <linux/kernel.h>
>> +#include <linux/slab.h>
>> +#include <linux/uuid.h>
>> +#include <linux/mdev.h>
>> +#include <linux/virtio_mdev.h>
>> +#include <linux/virtio.h>
>> +#include <linux/virtio_config.h>
>> +#include <linux/virtio_ring.h>
>> +#include "mdev_private.h"
>> +
>> +#define DRIVER_VERSION  "0.1"
>> +#define DRIVER_AUTHOR   "Red Hat Corporation"
>> +#define DRIVER_DESC     "VIRTIO based driver for Mediated device"
>> +
>> +#define to_virtio_mdev_device(dev) \
>> +	container_of(dev, struct virtio_mdev_device, vdev)
>> +
>> +struct virtio_mdev_device {
>> +	struct virtio_device vdev;
>> +	struct mdev_device *mdev;
>> +	unsigned long version;
>> +
>> +	struct virtqueue **vqs;
> Every lock must need a comment to describe what it locks.
> I don't see this lock is used in this patch. Please introduce in the patch that uses it.


Actually, it is used to sync the virtqueue list add and remove, but the
logic is missed in this patch.

Will fix it in next version.


>> +	spinlock_t lock;
>> +};
>> +
>> +struct virtio_mdev_vq_info {
>> +	/* the actual virtqueue */
>> +	struct virtqueue *vq;
>> +
>> +	/* the list node for the virtqueues list */
>> +	struct list_head node;
>> +};
>> +
>> +static struct mdev_device *vm_get_mdev(struct virtio_device *vdev) {
>> +	struct virtio_mdev_device *vm_dev = to_virtio_mdev_device(vdev);
>> +	struct mdev_device *mdev = vm_dev->mdev;
>> +
>> +	return mdev;
>> +}
>> +
>> +static const struct virtio_mdev_parent_ops *mdev_get_parent_ops(struct
>> +mdev_device *mdev) {
>> +	struct mdev_parent *parent = mdev->parent;
>> +
>> +	return parent->ops->device_ops;
>> +}
>> +
>> +static void virtio_mdev_get(struct virtio_device *vdev, unsigned offset,
>> +			    void *buf, unsigned len)
>> +{
>> +	struct mdev_device *mdev = vm_get_mdev(vdev);
>> +	const struct virtio_mdev_parent_ops *ops =
>> mdev_get_parent_ops(mdev);
>> +
>> +	ops->get_config(mdev, offset, buf, len); }
>> +
>> +static void virtio_mdev_set(struct virtio_device *vdev, unsigned offset,
>> +			    const void *buf, unsigned len)
>> +{
>> +	struct mdev_device *mdev = vm_get_mdev(vdev);
>> +	const struct virtio_mdev_parent_ops *ops =
>> mdev_get_parent_ops(mdev);
>> +
>> +	ops->set_config(mdev, offset, buf, len); }
>> +
>> +static u32 virtio_mdev_generation(struct virtio_device *vdev) {
>> +	struct mdev_device *mdev = vm_get_mdev(vdev);
>> +	const struct virtio_mdev_parent_ops *ops =
>> mdev_get_parent_ops(mdev);
>> +
>> +	return ops->get_generation(mdev);
>> +}
>> +
>> +static u8 virtio_mdev_get_status(struct virtio_device *vdev) {
>> +	struct mdev_device *mdev = vm_get_mdev(vdev);
>> +	const struct virtio_mdev_parent_ops *ops =
>> mdev_get_parent_ops(mdev);
>> +
>> +	return ops->get_status(mdev);
>> +}
>> +
>> +static void virtio_mdev_set_status(struct virtio_device *vdev, u8
>> +status) {
>> +	struct mdev_device *mdev = vm_get_mdev(vdev);
>> +	const struct virtio_mdev_parent_ops *ops =
>> mdev_get_parent_ops(mdev);
>> +
>> +	return ops->set_status(mdev, status);
>> +}
>> +
>> +static void virtio_mdev_reset(struct virtio_device *vdev) {
>> +	struct mdev_device *mdev = vm_get_mdev(vdev);
>> +	const struct virtio_mdev_parent_ops *ops =
>> mdev_get_parent_ops(mdev);
>> +
>> +	return ops->set_status(mdev, 0);
>> +}
>> +
>> +static bool virtio_mdev_notify(struct virtqueue *vq) {
>> +	struct mdev_device *mdev = vm_get_mdev(vq->vdev);
>> +	const struct virtio_mdev_parent_ops *ops =
>> mdev_get_parent_ops(mdev);
>> +
>> +	ops->kick_vq(mdev, vq->index);
>> +
>> +	return true;
>> +}
>> +
>> +static irqreturn_t virtio_mdev_config_cb(void *private) {
>> +	struct virtio_mdev_device *vm_dev = private;
>> +
>> +	virtio_config_changed(&vm_dev->vdev);
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static irqreturn_t virtio_mdev_virtqueue_cb(void *private) {
>> +	struct virtio_mdev_vq_info *info = private;
>> +
>> +	return vring_interrupt(0, info->vq);
>> +}
>> +
>> +static struct virtqueue *
>> +virtio_mdev_setup_vq(struct virtio_device *vdev, unsigned index,
>> +		     void (*callback)(struct virtqueue *vq),
>> +		     const char *name, bool ctx)
>> +{
>> +	struct mdev_device *mdev = vm_get_mdev(vdev);
>> +	const struct virtio_mdev_parent_ops *ops =
>> mdev_get_parent_ops(mdev);
>> +	struct virtio_mdev_vq_info *info;
>> +	struct virtio_mdev_callback cb;
>> +	struct virtqueue *vq;
>> +	u32 align, num;
>> +	u64 desc_addr, driver_addr, device_addr;
>> +	int err;
>> +
>> +	if (!name)
>> +		return NULL;
>> +
>> +	/* Queue shouldn't already be set up. */
>> +	if (ops->get_vq_ready(mdev, index)) {
>> +		err = -ENOENT;
>> +		goto error_available;
>> +	}
>> +
> No need for a goto, to single return done later.
> Just do 
> 	if (ops->get_vq_ready(mdev, index))
> 		return -ENOENT;


Ok, will fix.


>
>> +	/* Allocate and fill out our active queue description */
>> +	info = kmalloc(sizeof(*info), GFP_KERNEL);
>> +	if (!info) {
>> +		err = -ENOMEM;
>> +		goto error_kmalloc;
>> +	}
>> +
> Similar to above one.


Ok.


>
>> +	num = ops->get_queue_max(mdev);
>> +	if (num == 0) {
>> +		err = -ENOENT;
>> +		goto error_new_virtqueue;
>> +	}
>> +
>> +	/* Create the vring */
>> +	align = ops->get_vq_align(mdev);
>> +	vq = vring_create_virtqueue(index, num, align, vdev,
>> +				    true, true, ctx,
>> +				    virtio_mdev_notify, callback, name);
>> +	if (!vq) {
>> +		err = -ENOMEM;
>> +		goto error_new_virtqueue;
>> +	}
>> +
>> +	/* Setup virtqueue callback */
>> +	cb.callback = virtio_mdev_virtqueue_cb;
>> +	cb.private = info;
>> +	ops->set_vq_cb(mdev, index, &cb);
>> +	ops->set_vq_num(mdev, index, virtqueue_get_vring_size(vq));
>> +
>> +	desc_addr = virtqueue_get_desc_addr(vq);
>> +	driver_addr = virtqueue_get_avail_addr(vq);
>> +	device_addr = virtqueue_get_used_addr(vq);
>> +
>> +	if (ops->set_vq_address(mdev, index,
>> +				desc_addr, driver_addr,
>> +				device_addr)) {
>> +		err = -EINVAL;
>> +		goto err_vq;
>> +	}
>> +
>> +	ops->set_vq_ready(mdev, index, 1);
>> +
>> +	vq->priv = info;
>> +	info->vq = vq;
>> +
>> +	return vq;
>> +
>> +err_vq:
>> +	vring_del_virtqueue(vq);
>> +error_new_virtqueue:
>> +	ops->set_vq_ready(mdev, index, 0);
>> +	WARN_ON(ops->get_vq_ready(mdev, index));
>> +	kfree(info);
>> +error_kmalloc:
>> +error_available:
>> +	return ERR_PTR(err);
>> +
>> +}
>> +
>> +static void virtio_mdev_del_vq(struct virtqueue *vq) {
>> +	struct mdev_device *mdev = vm_get_mdev(vq->vdev);
>> +	const struct virtio_mdev_parent_ops *ops =
>> mdev_get_parent_ops(mdev);
>> +	struct virtio_mdev_vq_info *info = vq->priv;
>> +	unsigned int index = vq->index;
>> +
>> +	/* Select and deactivate the queue */
>> +	ops->set_vq_ready(mdev, index, 0);
>> +	WARN_ON(ops->get_vq_ready(mdev, index));
>> +
>> +	vring_del_virtqueue(vq);
>> +
>> +	kfree(info);
>> +}
>> +
>> +static void virtio_mdev_del_vqs(struct virtio_device *vdev) {
>> +	struct virtqueue *vq, *n;
>> +
>> +	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
>> +		virtio_mdev_del_vq(vq);
>> +}
>> +
>> +static int virtio_mdev_find_vqs(struct virtio_device *vdev, unsigned nvqs,
>> +				struct virtqueue *vqs[],
>> +				vq_callback_t *callbacks[],
>> +				const char * const names[],
>> +				const bool *ctx,
>> +				struct irq_affinity *desc)
>> +{
>> +	struct virtio_mdev_device *vm_dev = to_virtio_mdev_device(vdev);
>> +	struct mdev_device *mdev = vm_get_mdev(vdev);
>> +	const struct virtio_mdev_parent_ops *ops =
>> mdev_get_parent_ops(mdev);
>> +	struct virtio_mdev_callback cb;
>> +	int i, err, queue_idx = 0;
>> +
>> +	vm_dev->vqs = kmalloc_array(queue_idx, sizeof(*vm_dev->vqs),
>> +				    GFP_KERNEL);
>> +	if (!vm_dev->vqs)
>> +		return -ENOMEM;
>> +
>> +	for (i = 0; i < nvqs; ++i) {
>> +		if (!names[i]) {
>> +			vqs[i] = NULL;
>> +			continue;
>> +		}
>> +
>> +		vqs[i] = virtio_mdev_setup_vq(vdev, queue_idx++,
>> +					      callbacks[i], names[i], ctx ?
>> +					      ctx[i] : false);
>> +		if (IS_ERR(vqs[i])) {
>> +			err = PTR_ERR(vqs[i]);
>> +			goto err_setup_vq;
>> +		}
>> +	}
>> +
>> +	cb.callback = virtio_mdev_config_cb;
>> +	cb.private = vm_dev;
>> +	ops->set_config_cb(mdev, &cb);
>> +
>> +	return 0;
>> +
>> +err_setup_vq:
>> +	kfree(vm_dev->vqs);
>> +	virtio_mdev_del_vqs(vdev);
>> +	return err;
>> +}
>> +
>> +static u64 virtio_mdev_get_features(struct virtio_device *vdev) {
>> +	struct mdev_device *mdev = vm_get_mdev(vdev);
>> +	const struct virtio_mdev_parent_ops *ops =
>> mdev_get_parent_ops(mdev);
>> +
>> +	return ops->get_features(mdev);
>> +}
>> +
>> +static int virtio_mdev_finalize_features(struct virtio_device *vdev) {
>> +	struct mdev_device *mdev = vm_get_mdev(vdev);
>> +	const struct virtio_mdev_parent_ops *ops =
>> mdev_get_parent_ops(mdev);
>> +
>> +	/* Give virtio_ring a chance to accept features. */
>> +	vring_transport_features(vdev);
>> +
>> +	return ops->set_features(mdev, vdev->features); }
>> +
>> +static const char *virtio_mdev_bus_name(struct virtio_device *vdev) {
>> +	struct virtio_mdev_device *vm_dev = to_virtio_mdev_device(vdev);
>> +	struct mdev_device *mdev = vm_dev->mdev;
>> +
>> +	return dev_name(&mdev->dev);
>> +}
>> +
>> +static const struct virtio_config_ops virtio_mdev_config_ops = {
>> +	.get		= virtio_mdev_get,
>> +	.set		= virtio_mdev_set,
>> +	.generation	= virtio_mdev_generation,
>> +	.get_status	= virtio_mdev_get_status,
>> +	.set_status	= virtio_mdev_set_status,
>> +	.reset		= virtio_mdev_reset,
>> +	.find_vqs	= virtio_mdev_find_vqs,
>> +	.del_vqs	= virtio_mdev_del_vqs,
>> +	.get_features	= virtio_mdev_get_features,
>> +	.finalize_features = virtio_mdev_finalize_features,
>> +	.bus_name	= virtio_mdev_bus_name,
>> +};
>> +
>> +static void virtio_mdev_release_dev(struct device *_d) {
>> +	struct virtio_device *vdev =
>> +	       container_of(_d, struct virtio_device, dev);
>> +	struct virtio_mdev_device *vm_dev =
>> +	       container_of(vdev, struct virtio_mdev_device, vdev);
>> +
>> +	devm_kfree(_d, vm_dev);
>> +}
>> +
>> +static int virtio_mdev_probe(struct device *dev) {
>> +	struct mdev_device *mdev = to_mdev_device(dev);
>> +	const struct virtio_mdev_parent_ops *ops =
>> mdev_get_parent_ops(mdev);
>> +	struct virtio_mdev_device *vm_dev;
>> +	int rc;
>> +
>> +	vm_dev = devm_kzalloc(dev, sizeof(*vm_dev), GFP_KERNEL);
>> +	if (!vm_dev)
>> +		return -ENOMEM;
>> +
>> +	vm_dev->vdev.dev.parent = dev;
>> +	vm_dev->vdev.dev.release = virtio_mdev_release_dev;
>> +	vm_dev->vdev.config = &virtio_mdev_config_ops;
>> +	vm_dev->mdev = mdev;
>> +	vm_dev->vqs = NULL;
>> +	spin_lock_init(&vm_dev->lock);
>> +
>> +	vm_dev->version = ops->get_version(mdev);
>> +	if (vm_dev->version != 1) {
>> +		dev_err(dev, "Version %ld not supported!\n",
>> +			vm_dev->version);
>> +		return -ENXIO;
>> +	}
>> +
>> +	vm_dev->vdev.id.device = ops->get_device_id(mdev);
>> +	if (vm_dev->vdev.id.device == 0)
>> +		return -ENODEV;
>> +
>> +	vm_dev->vdev.id.vendor = ops->get_vendor_id(mdev);
>> +	rc = register_virtio_device(&vm_dev->vdev);
>> +	if (rc)
>> +		put_device(dev);
>> +
>> +	dev_set_drvdata(dev, vm_dev);
> No need to set drvdata when there is error returned from register_virtio_device().
>

Fixed in V2.


>> +
>> +	return rc;
>> +
> Extra line not needed.
>> +}


Fixed.


>> +
>> +static void virtio_mdev_remove(struct device *dev) {
>> +	struct virtio_mdev_device *vm_dev = dev_get_drvdata(dev);
>> +
>> +	unregister_virtio_device(&vm_dev->vdev);
>> +}
>> +
>> +static struct mdev_class_id id_table[] = {
>> +	{ MDEV_ID_VIRTIO },
>> +	{ 0 },
>> +};
>> +
>> +static struct mdev_driver virtio_mdev_driver = {
>> +	.name	= "virtio_mdev",
>> +	.probe	= virtio_mdev_probe,
>> +	.remove	= virtio_mdev_remove,
> No need for tab, just do single white space.


Yes, fixed.

Thanks


>> +	.id_table = id_table,
>> +};
>> +
>> +static int __init virtio_mdev_init(void) {
>> +	return mdev_register_driver(&virtio_mdev_driver, THIS_MODULE); }
>> +
>> +static void __exit virtio_mdev_exit(void) {
>> +	mdev_unregister_driver(&virtio_mdev_driver);
>> +}
>> +
>> +module_init(virtio_mdev_init)
>> +module_exit(virtio_mdev_exit)
>> +
>> +MODULE_VERSION(DRIVER_VERSION);
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_AUTHOR(DRIVER_AUTHOR);
>> +MODULE_DESCRIPTION(DRIVER_DESC);
>> --
>> 2.19.1

Re: [PATCH 5/6] vringh: fix copy direction of vringh_iov_push_kern()

[Alex Williamson]

On Mon, 23 Sep 2019 12:00:41 -0400
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Mon, Sep 23, 2019 at 09:45:59AM -0600, Alex Williamson wrote:
> > On Mon, 23 Sep 2019 21:03:30 +0800
> > Jason Wang <jasowang@redhat.com> wrote:
> >   
> > > We want to copy from iov to buf, so the direction was wrong.
> > > 
> > > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > > ---
> > >  drivers/vhost/vringh.c | 8 +++++++-
> > >  1 file changed, 7 insertions(+), 1 deletion(-)  
> > 
> > 
> > Why is this included in the series?  Seems like an unrelated fix being
> > held up within a proposal for a new feature.  Thanks,
> > 
> > Alex  
> 
> It's better to have it as patch 1/6, but it's a dependency of the
> example driver in the series. I can reorder when I apply.

It's a fix, please submit it separately through virtio/vhost channels,
then it will already be in the base kernel we use for the rest of the
series.  The remainder of the series certainly suggests a workflow
through the vfio tree rather than virtio/vhost.  Thanks,

Alex

> > > diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
> > > index 08ad0d1f0476..a0a2d74967ef 100644
> > > --- a/drivers/vhost/vringh.c
> > > +++ b/drivers/vhost/vringh.c
> > > @@ -852,6 +852,12 @@ static inline int xfer_kern(void *src, void *dst, size_t len)
> > >  	return 0;
> > >  }
> > >  
> > > +static inline int kern_xfer(void *dst, void *src, size_t len)
> > > +{
> > > +	memcpy(dst, src, len);
> > > +	return 0;
> > > +}
> > > +
> > >  /**
> > >   * vringh_init_kern - initialize a vringh for a kernelspace vring.
> > >   * @vrh: the vringh to initialize.
> > > @@ -958,7 +964,7 @@ EXPORT_SYMBOL(vringh_iov_pull_kern);
> > >  ssize_t vringh_iov_push_kern(struct vringh_kiov *wiov,
> > >  			     const void *src, size_t len)
> > >  {
> > > -	return vringh_iov_xfer(wiov, (void *)src, len, xfer_kern);
> > > +	return vringh_iov_xfer(wiov, (void *)src, len, kern_xfer);
> > >  }
> > >  EXPORT_SYMBOL(vringh_iov_push_kern);
> > >    

Re: [PATCH 5/6] vringh: fix copy direction of vringh_iov_push_kern()

[Jason Wang]

On 2019/9/24 下午10:04, Alex Williamson wrote:
> On Mon, 23 Sep 2019 12:00:41 -0400
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
>
>> On Mon, Sep 23, 2019 at 09:45:59AM -0600, Alex Williamson wrote:
>>> On Mon, 23 Sep 2019 21:03:30 +0800
>>> Jason Wang <jasowang@redhat.com> wrote:
>>>   
>>>> We want to copy from iov to buf, so the direction was wrong.
>>>>
>>>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>>>> ---
>>>>  drivers/vhost/vringh.c | 8 +++++++-
>>>>  1 file changed, 7 insertions(+), 1 deletion(-)  
>>> Why is this included in the series?  Seems like an unrelated fix being
>>> held up within a proposal for a new feature.  Thanks,
>>>
>>> Alex  
>> It's better to have it as patch 1/6, but it's a dependency of the
>> example driver in the series. I can reorder when I apply.
> It's a fix, please submit it separately through virtio/vhost channels,
> then it will already be in the base kernel we use for the rest of the
> series.  The remainder of the series certainly suggests a workflow
> through the vfio tree rather than virtio/vhost.  Thanks,
>
> Alex


Ok.

Thanks