> 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@xxxxxxxxxx] > >> 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@xxxxxxxxxx> > >> --- > >> 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@xxxxxxxxxx> > >> + */ > >> +#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
