[V2,6/8] mdev: introduce virtio device and its device ops

Submitted by Jason Wang on Sept. 24, 2019, 1:53 p.m.

Details

Message ID 20190924135332.14160-7-jasowang@redhat.com
State New
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Series "mdev based hardware virtio offloading support" ( rev: 3 ) in Intel GVT devel

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Commit Message

Jason Wang Sept. 24, 2019, 1:53 p.m.
This patch implements basic support for mdev driver that supports
virtio transport for kernel virtio driver.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 include/linux/mdev.h        |   2 +
 include/linux/virtio_mdev.h | 145 ++++++++++++++++++++++++++++++++++++
 2 files changed, 147 insertions(+)
 create mode 100644 include/linux/virtio_mdev.h

Patch hide | download patch | download mbox

diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 3414307311f1..73ac27b3b868 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -126,6 +126,8 @@  struct mdev_device *mdev_from_dev(struct device *dev);
 
 enum {
 	MDEV_ID_VFIO = 1,
+	MDEV_ID_VIRTIO = 2,
+	MDEV_ID_VHOST = 3,
 	/* New entries must be added here */
 };
 
diff --git a/include/linux/virtio_mdev.h b/include/linux/virtio_mdev.h
new file mode 100644
index 000000000000..d1a40a739266
--- /dev/null
+++ b/include/linux/virtio_mdev.h
@@ -0,0 +1,145 @@ 
+/* 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 <linux/mdev.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_device_ops - Structure to be registered for each
+ * mdev 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_device_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
+

Comments

On Tue, 24 Sep 2019 21:53:30 +0800
Jason Wang <jasowang@redhat.com> wrote:

> This patch implements basic support for mdev driver that supports
> virtio transport for kernel virtio driver.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  include/linux/mdev.h        |   2 +
>  include/linux/virtio_mdev.h | 145 ++++++++++++++++++++++++++++++++++++
>  2 files changed, 147 insertions(+)
>  create mode 100644 include/linux/virtio_mdev.h
> 
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> index 3414307311f1..73ac27b3b868 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -126,6 +126,8 @@ struct mdev_device *mdev_from_dev(struct device *dev);
>  
>  enum {
>  	MDEV_ID_VFIO = 1,
> +	MDEV_ID_VIRTIO = 2,
> +	MDEV_ID_VHOST = 3,

MDEV_ID_VHOST isn't used yet here.  Also, given the strong
interdependence between the class_id and the ops structure, we might
wand to define them in the same place.  Thanks,

Alex

>  	/* New entries must be added here */
>  };
>  
> diff --git a/include/linux/virtio_mdev.h b/include/linux/virtio_mdev.h
> new file mode 100644
> index 000000000000..d1a40a739266
> --- /dev/null
> +++ b/include/linux/virtio_mdev.h
> @@ -0,0 +1,145 @@
> +/* 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 <linux/mdev.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_device_ops - Structure to be registered for each
> + * mdev 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_device_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
> +
> From: Jason Wang [mailto:jasowang@redhat.com]
> Sent: Tuesday, September 24, 2019 9:54 PM
> 
> This patch implements basic support for mdev driver that supports
> virtio transport for kernel virtio driver.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  include/linux/mdev.h        |   2 +
>  include/linux/virtio_mdev.h | 145
> ++++++++++++++++++++++++++++++++++++
>  2 files changed, 147 insertions(+)
>  create mode 100644 include/linux/virtio_mdev.h
> 
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> index 3414307311f1..73ac27b3b868 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -126,6 +126,8 @@ struct mdev_device *mdev_from_dev(struct device
> *dev);
> 
>  enum {
>  	MDEV_ID_VFIO = 1,
> +	MDEV_ID_VIRTIO = 2,
> +	MDEV_ID_VHOST = 3,
>  	/* New entries must be added here */
>  };
> 
> diff --git a/include/linux/virtio_mdev.h b/include/linux/virtio_mdev.h
> new file mode 100644
> index 000000000000..d1a40a739266
> --- /dev/null
> +++ b/include/linux/virtio_mdev.h
> @@ -0,0 +1,145 @@
> +/* 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 <linux/mdev.h>
> +#include <uapi/linux/vhost.h>
> +
> +#define VIRTIO_MDEV_DEVICE_API_STRING		"virtio-mdev"
> +#define VIRTIO_MDEV_VERSION 0x1

Just be curious. is this version identical to virtio spec version that below
callbacks are created for, or just irrelevant?

> +
> +struct virtio_mdev_callback {
> +	irqreturn_t (*callback)(void *data);
> +	void *private;
> +};
> +
> +/**
> + * struct vfio_mdev_device_ops - Structure to be registered for each
> + * mdev 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

configuration (and similar typos downward)

> + *				@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_device_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);
> +};

I'm not sure how stable above ops are. Does it make sense if defining
just two callbacks here, e.g. vq_ctrl and device_ctrl, and then let the
vendor driver to handle specific ops in each category (similar to how
ioctl works)?

Thanks
Kevin
On 2019/9/25 上午7:06, Alex Williamson wrote:
> On Tue, 24 Sep 2019 21:53:30 +0800
> Jason Wang <jasowang@redhat.com> wrote:
>
>> This patch implements basic support for mdev driver that supports
>> virtio transport for kernel virtio driver.
>>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>  include/linux/mdev.h        |   2 +
>>  include/linux/virtio_mdev.h | 145 ++++++++++++++++++++++++++++++++++++
>>  2 files changed, 147 insertions(+)
>>  create mode 100644 include/linux/virtio_mdev.h
>>
>> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
>> index 3414307311f1..73ac27b3b868 100644
>> --- a/include/linux/mdev.h
>> +++ b/include/linux/mdev.h
>> @@ -126,6 +126,8 @@ struct mdev_device *mdev_from_dev(struct device *dev);
>>  
>>  enum {
>>  	MDEV_ID_VFIO = 1,
>> +	MDEV_ID_VIRTIO = 2,
>> +	MDEV_ID_VHOST = 3,
> MDEV_ID_VHOST isn't used yet here. 


Yes, just want to reserve one but it look too early to do that.


>  Also, given the strong
> interdependence between the class_id and the ops structure, we might
> wand to define them in the same place.  Thanks,
>
> Alex


Yes, as you suggest in patch 5/8.

Thanks


>
>>  	/* New entries must be added here */
>>  };
>>  
>> diff --git a/include/linux/virtio_mdev.h b/include/linux/virtio_mdev.h
>> new file mode 100644
>> index 000000000000..d1a40a739266
>> --- /dev/null
>> +++ b/include/linux/virtio_mdev.h
>> @@ -0,0 +1,145 @@
>> +/* 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 <linux/mdev.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_device_ops - Structure to be registered for each
>> + * mdev 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_device_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
>> +
On 2019/9/25 下午5:09, Tian, Kevin wrote:
>> From: Jason Wang [mailto:jasowang@redhat.com]
>> Sent: Tuesday, September 24, 2019 9:54 PM
>>
>> This patch implements basic support for mdev driver that supports
>> virtio transport for kernel virtio driver.
>>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>   include/linux/mdev.h        |   2 +
>>   include/linux/virtio_mdev.h | 145
>> ++++++++++++++++++++++++++++++++++++
>>   2 files changed, 147 insertions(+)
>>   create mode 100644 include/linux/virtio_mdev.h
>>
>> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
>> index 3414307311f1..73ac27b3b868 100644
>> --- a/include/linux/mdev.h
>> +++ b/include/linux/mdev.h
>> @@ -126,6 +126,8 @@ struct mdev_device *mdev_from_dev(struct device
>> *dev);
>>
>>   enum {
>>   	MDEV_ID_VFIO = 1,
>> +	MDEV_ID_VIRTIO = 2,
>> +	MDEV_ID_VHOST = 3,
>>   	/* New entries must be added here */
>>   };
>>
>> diff --git a/include/linux/virtio_mdev.h b/include/linux/virtio_mdev.h
>> new file mode 100644
>> index 000000000000..d1a40a739266
>> --- /dev/null
>> +++ b/include/linux/virtio_mdev.h
>> @@ -0,0 +1,145 @@
>> +/* 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 <linux/mdev.h>
>> +#include <uapi/linux/vhost.h>
>> +
>> +#define VIRTIO_MDEV_DEVICE_API_STRING		"virtio-mdev"
>> +#define VIRTIO_MDEV_VERSION 0x1
> Just be curious. is this version identical to virtio spec version that below
> callbacks are created for, or just irrelevant?


It could be a hint but basically it's a way for userspace driver 
compatibility. For kernel we don't need this.


>
>> +
>> +struct virtio_mdev_callback {
>> +	irqreturn_t (*callback)(void *data);
>> +	void *private;
>> +};
>> +
>> +/**
>> + * struct vfio_mdev_device_ops - Structure to be registered for each
>> + * mdev 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
> configuration (and similar typos downward)


Let me fix.


>
>> + *				@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_device_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);
>> +};
> I'm not sure how stable above ops are.


It's the kernel internal API, so there's no strict requirement for this. 
We will export a version value for userspace for compatibility.


> Does it make sense if defining
> just two callbacks here, e.g. vq_ctrl and device_ctrl, and then let the
> vendor driver to handle specific ops in each category (similar to how
> ioctl works)?


My understanding is that it introduce another indirection, you still 
need to differ from different command, and it's less flexible than 
direct callback.

What's the value of doing this?

Thanks


>
> Thanks
> Kevin
>
On Wed, Sep 25, 2019 at 08:45:21PM +0800, Jason Wang wrote:
> 
> On 2019/9/25 下午5:09, Tian, Kevin wrote:
> > > From: Jason Wang [mailto:jasowang@redhat.com]
> > > Sent: Tuesday, September 24, 2019 9:54 PM
> > > 
> > > This patch implements basic support for mdev driver that supports
> > > virtio transport for kernel virtio driver.
> > > 
> > > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > > ---
> > >   include/linux/mdev.h        |   2 +
> > >   include/linux/virtio_mdev.h | 145
> > > ++++++++++++++++++++++++++++++++++++
> > >   2 files changed, 147 insertions(+)
> > >   create mode 100644 include/linux/virtio_mdev.h
> > > 
> > > diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> > > index 3414307311f1..73ac27b3b868 100644
> > > --- a/include/linux/mdev.h
> > > +++ b/include/linux/mdev.h
> > > @@ -126,6 +126,8 @@ struct mdev_device *mdev_from_dev(struct device
> > > *dev);
> > > 
> > >   enum {
> > >   	MDEV_ID_VFIO = 1,
> > > +	MDEV_ID_VIRTIO = 2,
> > > +	MDEV_ID_VHOST = 3,
> > >   	/* New entries must be added here */
> > >   };
> > > 
> > > diff --git a/include/linux/virtio_mdev.h b/include/linux/virtio_mdev.h
> > > new file mode 100644
> > > index 000000000000..d1a40a739266
> > > --- /dev/null
> > > +++ b/include/linux/virtio_mdev.h
> > > @@ -0,0 +1,145 @@
> > > +/* 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 <linux/mdev.h>
> > > +#include <uapi/linux/vhost.h>
> > > +
> > > +#define VIRTIO_MDEV_DEVICE_API_STRING		"virtio-mdev"
> > > +#define VIRTIO_MDEV_VERSION 0x1
> > Just be curious. is this version identical to virtio spec version that below
> > callbacks are created for, or just irrelevant?
> 
> 
> It could be a hint but basically it's a way for userspace driver
> compatibility. For kernel we don't need this.
> 
> 
> > 
> > > +
> > > +struct virtio_mdev_callback {
> > > +	irqreturn_t (*callback)(void *data);
> > > +	void *private;
> > > +};
> > > +
> > > +/**
> > > + * struct vfio_mdev_device_ops - Structure to be registered for each
> > > + * mdev 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
> > configuration (and similar typos downward)
> 
> 
> Let me fix.
> 
> 
> > 
> > > + *				@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_device_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);
> > > +};
> > I'm not sure how stable above ops are.
> 
> 
> It's the kernel internal API, so there's no strict requirement for this. We
> will export a version value for userspace for compatibility.

Given it's tied to virtio we probably want kernel+userspace
feature bits?

> 
> > Does it make sense if defining
> > just two callbacks here, e.g. vq_ctrl and device_ctrl, and then let the
> > vendor driver to handle specific ops in each category (similar to how
> > ioctl works)?
> 
> 
> My understanding is that it introduce another indirection, you still need to
> differ from different command, and it's less flexible than direct callback.
> 
> What's the value of doing this?
> 
> Thanks
> 
> 
> > 
> > Thanks
> > Kevin
> >
> From: Jason Wang

> Sent: Wednesday, September 25, 2019 8:45 PM

> 

> 

> On 2019/9/25 下午5:09, Tian, Kevin wrote:

> >> From: Jason Wang [mailto:jasowang@redhat.com]

> >> Sent: Tuesday, September 24, 2019 9:54 PM

> >>

> >> This patch implements basic support for mdev driver that supports

> >> virtio transport for kernel virtio driver.

> >>

> >> Signed-off-by: Jason Wang <jasowang@redhat.com>

> >> ---

> >>   include/linux/mdev.h        |   2 +

> >>   include/linux/virtio_mdev.h | 145

> >> ++++++++++++++++++++++++++++++++++++

> >>   2 files changed, 147 insertions(+)

> >>   create mode 100644 include/linux/virtio_mdev.h

> >>

> >> diff --git a/include/linux/mdev.h b/include/linux/mdev.h

> >> index 3414307311f1..73ac27b3b868 100644

> >> --- a/include/linux/mdev.h

> >> +++ b/include/linux/mdev.h

> >> @@ -126,6 +126,8 @@ struct mdev_device *mdev_from_dev(struct

> device

> >> *dev);

> >>

> >>   enum {

> >>   	MDEV_ID_VFIO = 1,

> >> +	MDEV_ID_VIRTIO = 2,

> >> +	MDEV_ID_VHOST = 3,

> >>   	/* New entries must be added here */

> >>   };

> >>

> >> diff --git a/include/linux/virtio_mdev.h b/include/linux/virtio_mdev.h

> >> new file mode 100644

> >> index 000000000000..d1a40a739266

> >> --- /dev/null

> >> +++ b/include/linux/virtio_mdev.h

> >> @@ -0,0 +1,145 @@

> >> +/* 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 <linux/mdev.h>

> >> +#include <uapi/linux/vhost.h>

> >> +

> >> +#define VIRTIO_MDEV_DEVICE_API_STRING		"virtio-

> mdev"

> >> +#define VIRTIO_MDEV_VERSION 0x1

> > Just be curious. is this version identical to virtio spec version that below

> > callbacks are created for, or just irrelevant?

> 

> 

> It could be a hint but basically it's a way for userspace driver

> compatibility. For kernel we don't need this.

> 

> 

> >

> >> +

> >> +struct virtio_mdev_callback {

> >> +	irqreturn_t (*callback)(void *data);

> >> +	void *private;

> >> +};

> >> +

> >> +/**

> >> + * struct vfio_mdev_device_ops - Structure to be registered for each

> >> + * mdev 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

> > configuration (and similar typos downward)

> 

> 

> Let me fix.

> 

> 

> >

> >> + *				@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_device_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);

> >> +};

> > I'm not sure how stable above ops are.

> 

> 

> It's the kernel internal API, so there's no strict requirement for this.

> We will export a version value for userspace for compatibility.

> 

> 

> > Does it make sense if defining

> > just two callbacks here, e.g. vq_ctrl and device_ctrl, and then let the

> > vendor driver to handle specific ops in each category (similar to how

> > ioctl works)?

> 

> 

> My understanding is that it introduce another indirection, you still

> need to differ from different command, and it's less flexible than

> direct callback.

> 

> What's the value of doing this?

> 


I just thought doing so may provide better compatibility to the
parent driver. Even when new op is introduced, a parent driver
that was developed against the old set can still be loaded in the
new kernel. It just returns error when unrecognized ops are
routed through vq_ctrl and device_ctrl, if the userspace doesn't
favor the exposed version value. But if above ops set is pretty
stable, then this comment can be ignored.

Thanks
Kevin
On 2019/9/25 下午9:21, Michael S. Tsirkin wrote:
> On Wed, Sep 25, 2019 at 08:45:21PM +0800, Jason Wang wrote:
>> On 2019/9/25 下午5:09, Tian, Kevin wrote:
>>>> From: Jason Wang [mailto:jasowang@redhat.com]
>>>> Sent: Tuesday, September 24, 2019 9:54 PM
>>>>
>>>> This patch implements basic support for mdev driver that supports
>>>> virtio transport for kernel virtio driver.
>>>>
>>>> Signed-off-by: Jason Wang<jasowang@redhat.com>
>>>> ---
>>>>    include/linux/mdev.h        |   2 +
>>>>    include/linux/virtio_mdev.h | 145
>>>> ++++++++++++++++++++++++++++++++++++
>>>>    2 files changed, 147 insertions(+)
>>>>    create mode 100644 include/linux/virtio_mdev.h
>>>>
>>>> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
>>>> index 3414307311f1..73ac27b3b868 100644
>>>> --- a/include/linux/mdev.h
>>>> +++ b/include/linux/mdev.h
>>>> @@ -126,6 +126,8 @@ struct mdev_device *mdev_from_dev(struct device
>>>> *dev);
>>>>
>>>>    enum {
>>>>    	MDEV_ID_VFIO = 1,
>>>> +	MDEV_ID_VIRTIO = 2,
>>>> +	MDEV_ID_VHOST = 3,
>>>>    	/* New entries must be added here */
>>>>    };
>>>>
>>>> diff --git a/include/linux/virtio_mdev.h b/include/linux/virtio_mdev.h
>>>> new file mode 100644
>>>> index 000000000000..d1a40a739266
>>>> --- /dev/null
>>>> +++ b/include/linux/virtio_mdev.h
>>>> @@ -0,0 +1,145 @@
>>>> +/* 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 <linux/mdev.h>
>>>> +#include <uapi/linux/vhost.h>
>>>> +
>>>> +#define VIRTIO_MDEV_DEVICE_API_STRING		"virtio-mdev"
>>>> +#define VIRTIO_MDEV_VERSION 0x1
>>> Just be curious. is this version identical to virtio spec version that below
>>> callbacks are created for, or just irrelevant?
>> It could be a hint but basically it's a way for userspace driver
>> compatibility. For kernel we don't need this.
>>
>>
>>>> +
>>>> +struct virtio_mdev_callback {
>>>> +	irqreturn_t (*callback)(void *data);
>>>> +	void *private;
>>>> +};
>>>> +
>>>> +/**
>>>> + * struct vfio_mdev_device_ops - Structure to be registered for each
>>>> + * mdev 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
>>> configuration (and similar typos downward)
>> Let me fix.
>>
>>
>>>> + *				@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_device_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);
>>>> +};
>>> I'm not sure how stable above ops are.
>> It's the kernel internal API, so there's no strict requirement for this. We
>> will export a version value for userspace for compatibility.
> Given it's tied to virtio we probably want kernel+userspace
> feature bits?


Yes, then I think we could probably have a version field inside e.g 
device_ops structure. Then it could be fetched from both kernel and 
userspace driver.

Thanks


>
On 2019/9/26 上午8:48, Tian, Kevin wrote:
>>>> +};
>>> I'm not sure how stable above ops are.
>> It's the kernel internal API, so there's no strict requirement for this.
>> We will export a version value for userspace for compatibility.
>>
>>
>>> Does it make sense if defining
>>> just two callbacks here, e.g. vq_ctrl and device_ctrl, and then let the
>>> vendor driver to handle specific ops in each category (similar to how
>>> ioctl works)?
>> My understanding is that it introduce another indirection, you still
>> need to differ from different command, and it's less flexible than
>> direct callback.
>>
>> What's the value of doing this?
>>
> I just thought doing so may provide better compatibility to the
> parent driver. Even when new op is introduced, a parent driver
> that was developed against the old set can still be loaded in the
> new kernel. It just returns error when unrecognized ops are
> routed through vq_ctrl and device_ctrl, if the userspace doesn't
> favor the exposed version value. But if above ops set is pretty
> stable, then this comment can be ignored.


This is really good point, we should keep it stable as a real transport. 
And when there's major changes, we should advertise through version then 
we can provide a new set of functions.

Thanks


>
> Thanks
> Kevin
On Thu, Sep 26, 2019 at 12:04:46PM +0800, Jason Wang wrote:
> > > > I'm not sure how stable above ops are.
> > > It's the kernel internal API, so there's no strict requirement for this. We
> > > will export a version value for userspace for compatibility.
> > Given it's tied to virtio we probably want kernel+userspace
> > feature bits?
> 
> 
> Yes, then I think we could probably have a version field inside e.g
> device_ops structure. Then it could be fetched from both kernel and
> userspace driver.
> 
> Thanks
> 


my point was feature bits not a version number.

> >
On 2019/9/26 下午4:21, Michael S. Tsirkin wrote:
> On Thu, Sep 26, 2019 at 12:04:46PM +0800, Jason Wang wrote:
>>>>> I'm not sure how stable above ops are.
>>>> It's the kernel internal API, so there's no strict requirement for this. We
>>>> will export a version value for userspace for compatibility.
>>> Given it's tied to virtio we probably want kernel+userspace
>>> feature bits?
>>
>> Yes, then I think we could probably have a version field inside e.g
>> device_ops structure. Then it could be fetched from both kernel and
>> userspace driver.
>>
>> Thanks
>>
>
> my point was feature bits not a version number.


Something like backend_feature that current vhost_net did?

Thanks


>
On Thu, Sep 26, 2019 at 06:48:54PM +0800, Jason Wang wrote:
> 
> On 2019/9/26 下午4:21, Michael S. Tsirkin wrote:
> > On Thu, Sep 26, 2019 at 12:04:46PM +0800, Jason Wang wrote:
> > > > > > I'm not sure how stable above ops are.
> > > > > It's the kernel internal API, so there's no strict requirement for this. We
> > > > > will export a version value for userspace for compatibility.
> > > > Given it's tied to virtio we probably want kernel+userspace
> > > > feature bits?
> > > 
> > > Yes, then I think we could probably have a version field inside e.g
> > > device_ops structure. Then it could be fetched from both kernel and
> > > userspace driver.
> > > 
> > > Thanks
> > > 
> > 
> > my point was feature bits not a version number.
> 
> 
> Something like backend_feature that current vhost_net did?
> 
> Thanks
> 
> 
> > 

right
On 2019/9/25 上午7:06, Alex Williamson wrote:
> On Tue, 24 Sep 2019 21:53:30 +0800
> Jason Wang<jasowang@redhat.com>  wrote:
>
>> This patch implements basic support for mdev driver that supports
>> virtio transport for kernel virtio driver.
>>
>> Signed-off-by: Jason Wang<jasowang@redhat.com>
>> ---
>>   include/linux/mdev.h        |   2 +
>>   include/linux/virtio_mdev.h | 145 ++++++++++++++++++++++++++++++++++++
>>   2 files changed, 147 insertions(+)
>>   create mode 100644 include/linux/virtio_mdev.h
>>
>> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
>> index 3414307311f1..73ac27b3b868 100644
>> --- a/include/linux/mdev.h
>> +++ b/include/linux/mdev.h
>> @@ -126,6 +126,8 @@ struct mdev_device *mdev_from_dev(struct device *dev);
>>   
>>   enum {
>>   	MDEV_ID_VFIO = 1,
>> +	MDEV_ID_VIRTIO = 2,
>> +	MDEV_ID_VHOST = 3,
> MDEV_ID_VHOST isn't used yet here.  Also, given the strong
> interdependence between the class_id and the ops structure, we might
> wand to define them in the same place.  Thanks,
>
> Alex
>

Rethink about this,  I believe it's better to define the device ops in 
their own headers, and one set of device ops could be used for two 
classes (e.g both virtio and vhost). And to avoid a duplicated ID 
definition. I tend to keep this in the common mdev.h header.

Thanks
Hi Alex,


> -----Original Message-----
> From: Alex Williamson <alex.williamson@redhat.com>
> Sent: Tuesday, September 24, 2019 6:07 PM
> To: Jason Wang <jasowang@redhat.com>
> Cc: 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; mst@redhat.com; tiwei.bie@intel.com;
> 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>; christophe.de.dinechin@gmail.com;
> kevin.tian@intel.com
> Subject: Re: [PATCH V2 6/8] mdev: introduce virtio device and its device ops
> 
> On Tue, 24 Sep 2019 21:53:30 +0800
> Jason Wang <jasowang@redhat.com> wrote:
> 
> > This patch implements basic support for mdev driver that supports
> > virtio transport for kernel virtio driver.
> >
> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > ---
> >  include/linux/mdev.h        |   2 +
> >  include/linux/virtio_mdev.h | 145
> > ++++++++++++++++++++++++++++++++++++
> >  2 files changed, 147 insertions(+)
> >  create mode 100644 include/linux/virtio_mdev.h
> >
> > diff --git a/include/linux/mdev.h b/include/linux/mdev.h index
> > 3414307311f1..73ac27b3b868 100644
> > --- a/include/linux/mdev.h
> > +++ b/include/linux/mdev.h
> > @@ -126,6 +126,8 @@ struct mdev_device *mdev_from_dev(struct device
> > *dev);
> >
> >  enum {
> >  	MDEV_ID_VFIO = 1,
> > +	MDEV_ID_VIRTIO = 2,
> > +	MDEV_ID_VHOST = 3,
> 
> MDEV_ID_VHOST isn't used yet here.  Also, given the strong interdependence
> between the class_id and the ops structure, we might wand to define them in
> the same place.  Thanks,
> 

When mlx5_core creates mdevs (parent->ops->create() and it wants to bind to mlx5 mdev driver (which does mdev_register_driver()), 
mlx5 core driver will publish MDEV_ID_MLX5_NET defined in central place as include/linux/mdev.h without any ops structure.
Because such ops are not relevant. It uses usual, standard ops probe() remove() on the mdev (similar to a regular PCI device).
So for VHOST case ops may be closely related to ID, but not for other type of ID.

Just want to make sure, that scope of ID covers this case.
On Fri, 27 Sep 2019 16:25:13 +0000
Parav Pandit <parav@mellanox.com> wrote:

> Hi Alex,
> 
> 
> > -----Original Message-----
> > From: Alex Williamson <alex.williamson@redhat.com>
> > Sent: Tuesday, September 24, 2019 6:07 PM
> > To: Jason Wang <jasowang@redhat.com>
> > Cc: 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; mst@redhat.com; tiwei.bie@intel.com;
> > 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>; christophe.de.dinechin@gmail.com;
> > kevin.tian@intel.com
> > Subject: Re: [PATCH V2 6/8] mdev: introduce virtio device and its device ops
> > 
> > On Tue, 24 Sep 2019 21:53:30 +0800
> > Jason Wang <jasowang@redhat.com> wrote:
> >   
> > > This patch implements basic support for mdev driver that supports
> > > virtio transport for kernel virtio driver.
> > >
> > > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > > ---
> > >  include/linux/mdev.h        |   2 +
> > >  include/linux/virtio_mdev.h | 145
> > > ++++++++++++++++++++++++++++++++++++
> > >  2 files changed, 147 insertions(+)
> > >  create mode 100644 include/linux/virtio_mdev.h
> > >
> > > diff --git a/include/linux/mdev.h b/include/linux/mdev.h index
> > > 3414307311f1..73ac27b3b868 100644
> > > --- a/include/linux/mdev.h
> > > +++ b/include/linux/mdev.h
> > > @@ -126,6 +126,8 @@ struct mdev_device *mdev_from_dev(struct device
> > > *dev);
> > >
> > >  enum {
> > >  	MDEV_ID_VFIO = 1,
> > > +	MDEV_ID_VIRTIO = 2,
> > > +	MDEV_ID_VHOST = 3,  
> > 
> > MDEV_ID_VHOST isn't used yet here.  Also, given the strong interdependence
> > between the class_id and the ops structure, we might wand to define them in
> > the same place.  Thanks,
> >   
> 
> When mlx5_core creates mdevs (parent->ops->create() and it wants to
> bind to mlx5 mdev driver (which does mdev_register_driver()), mlx5
> core driver will publish MDEV_ID_MLX5_NET defined in central place as
> include/linux/mdev.h without any ops structure. Because such ops are
> not relevant. It uses usual, standard ops probe() remove() on the
> mdev (similar to a regular PCI device). So for VHOST case ops may be
> closely related to ID, but not for other type of ID.
> 
> Just want to make sure, that scope of ID covers this case.

AIUI, these device-ops are primarily meant to have 1:N multiplexing of
the mdev bus driver.  One mdev bus driver supports N vendor drivers via
a common "protocol" defined by this structure.  vfio-mdev supports
GVT-g, GRID, and several sample drivers.  I think Jason and Tiwei are
attempting something similar if we have multiple vendors that may
provide virtio/vhost parent drivers.  If you have a 1:1 model with
mlx5 where you're not trying to abstract a common channel between the
mdev bus driver and the mdev vendor driver, then I suppose you might
not use the device-ops capabilities of the mdev-core.  Did I interpret
the question correctly?  I think that's probably fine, mdev-core
shouldn't have any dependencies on the device-ops and we shouldn't
really be dictating the bus/vendor link through mdev.  Thanks,

Alex
On 2019/10/1 上午5:36, Alex Williamson wrote:
> On Fri, 27 Sep 2019 16:25:13 +0000
> Parav Pandit <parav@mellanox.com> wrote:
>
>> Hi Alex,
>>
>>
>>> -----Original Message-----
>>> From: Alex Williamson <alex.williamson@redhat.com>
>>> Sent: Tuesday, September 24, 2019 6:07 PM
>>> To: Jason Wang <jasowang@redhat.com>
>>> Cc: 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; mst@redhat.com; tiwei.bie@intel.com;
>>> 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>; christophe.de.dinechin@gmail.com;
>>> kevin.tian@intel.com
>>> Subject: Re: [PATCH V2 6/8] mdev: introduce virtio device and its device ops
>>>
>>> On Tue, 24 Sep 2019 21:53:30 +0800
>>> Jason Wang <jasowang@redhat.com> wrote:
>>>    
>>>> This patch implements basic support for mdev driver that supports
>>>> virtio transport for kernel virtio driver.
>>>>
>>>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>>>> ---
>>>>   include/linux/mdev.h        |   2 +
>>>>   include/linux/virtio_mdev.h | 145
>>>> ++++++++++++++++++++++++++++++++++++
>>>>   2 files changed, 147 insertions(+)
>>>>   create mode 100644 include/linux/virtio_mdev.h
>>>>
>>>> diff --git a/include/linux/mdev.h b/include/linux/mdev.h index
>>>> 3414307311f1..73ac27b3b868 100644
>>>> --- a/include/linux/mdev.h
>>>> +++ b/include/linux/mdev.h
>>>> @@ -126,6 +126,8 @@ struct mdev_device *mdev_from_dev(struct device
>>>> *dev);
>>>>
>>>>   enum {
>>>>   	MDEV_ID_VFIO = 1,
>>>> +	MDEV_ID_VIRTIO = 2,
>>>> +	MDEV_ID_VHOST = 3,
>>> MDEV_ID_VHOST isn't used yet here.  Also, given the strong interdependence
>>> between the class_id and the ops structure, we might wand to define them in
>>> the same place.  Thanks,
>>>    
>> When mlx5_core creates mdevs (parent->ops->create() and it wants to
>> bind to mlx5 mdev driver (which does mdev_register_driver()), mlx5
>> core driver will publish MDEV_ID_MLX5_NET defined in central place as
>> include/linux/mdev.h without any ops structure. Because such ops are
>> not relevant. It uses usual, standard ops probe() remove() on the
>> mdev (similar to a regular PCI device). So for VHOST case ops may be
>> closely related to ID, but not for other type of ID.
>>
>> Just want to make sure, that scope of ID covers this case.
> AIUI, these device-ops are primarily meant to have 1:N multiplexing of
> the mdev bus driver.  One mdev bus driver supports N vendor drivers via
> a common "protocol" defined by this structure.  vfio-mdev supports
> GVT-g, GRID, and several sample drivers.  I think Jason and Tiwei are
> attempting something similar if we have multiple vendors that may
> provide virtio/vhost parent drivers.


Exactly.


>   If you have a 1:1 model with
> mlx5 where you're not trying to abstract a common channel between the
> mdev bus driver and the mdev vendor driver, then I suppose you might
> not use the device-ops capabilities of the mdev-core.


Yes, current proposed API allows NULL to be passed as device ops.

Thanks


>   Did I interpret
> the question correctly?  I think that's probably fine, mdev-core
> shouldn't have any dependencies on the device-ops and we shouldn't
> really be dictating the bus/vendor link through mdev.  Thanks,
>
> Alex
On 2019/9/25 上午7:06, Alex Williamson wrote:
> On Tue, 24 Sep 2019 21:53:30 +0800
> Jason Wang<jasowang@redhat.com>  wrote:
>
>> This patch implements basic support for mdev driver that supports
>> virtio transport for kernel virtio driver.
>>
>> Signed-off-by: Jason Wang<jasowang@redhat.com>
>> ---
>>   include/linux/mdev.h        |   2 +
>>   include/linux/virtio_mdev.h | 145 ++++++++++++++++++++++++++++++++++++
>>   2 files changed, 147 insertions(+)
>>   create mode 100644 include/linux/virtio_mdev.h
>>
>> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
>> index 3414307311f1..73ac27b3b868 100644
>> --- a/include/linux/mdev.h
>> +++ b/include/linux/mdev.h
>> @@ -126,6 +126,8 @@ struct mdev_device *mdev_from_dev(struct device *dev);
>>   
>>   enum {
>>   	MDEV_ID_VFIO = 1,
>> +	MDEV_ID_VIRTIO = 2,
>> +	MDEV_ID_VHOST = 3,
> MDEV_ID_VHOST isn't used yet here.  Also, given the strong
> interdependence between the class_id and the ops structure, we might
> wand to define them in the same place.  Thanks,
>
> Alex
>

Rethink about this, consider we may have more types of devices supported 
in the future, moving all device_ops to mdev.h seems unnecessary. I 
prefer to keep the device_ops into their own headers.

Thanks