[Intel-gfx] [PATCH V2 6/8] mdev: introduce virtio device and its device ops
Jason Wang
jasowang at redhat.com
Thu Sep 26 04:04:46 UTC 2019
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 at 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 at 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 at 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
>
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