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    SubjectRe: [PATCH V5 4/6] mdev: introduce virtio device and its device ops
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    On 10/23/2019 9:07 PM, Jason Wang 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>
    > ---
    > drivers/vfio/mdev/mdev_core.c | 20 ++++
    > drivers/vfio/mdev/mdev_private.h | 2 +
    > include/linux/mdev.h | 6 ++
    > include/linux/virtio_mdev_ops.h | 159 +++++++++++++++++++++++++++++++
    > 4 files changed, 187 insertions(+)
    > create mode 100644 include/linux/virtio_mdev_ops.h
    >
    > diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
    > index 555bd61d8c38..9b00c3513120 100644
    > --- a/drivers/vfio/mdev/mdev_core.c
    > +++ b/drivers/vfio/mdev/mdev_core.c
    > @@ -76,6 +76,26 @@ const struct vfio_mdev_device_ops *mdev_get_vfio_ops(struct mdev_device *mdev)
    > }
    > EXPORT_SYMBOL(mdev_get_vfio_ops);
    >
    > +/* Specify the virtio device ops for the mdev device, this
    > + * must be called during create() callback for virtio mdev device.
    > + */
    > +void mdev_set_virtio_ops(struct mdev_device *mdev,
    > + const struct virtio_mdev_device_ops *virtio_ops)
    > +{
    > + mdev_set_class(mdev, MDEV_CLASS_ID_VIRTIO);
    > + mdev->virtio_ops = virtio_ops;
    > +}
    > +EXPORT_SYMBOL(mdev_set_virtio_ops);
    > +
    > +/* Get the virtio device ops for the mdev device. */
    > +const struct virtio_mdev_device_ops *
    > +mdev_get_virtio_ops(struct mdev_device *mdev)
    > +{
    > + WARN_ON(mdev->class_id != MDEV_CLASS_ID_VIRTIO);
    > + return mdev->virtio_ops;
    > +}
    > +EXPORT_SYMBOL(mdev_get_virtio_ops);
    > +
    > struct device *mdev_dev(struct mdev_device *mdev)
    > {
    > return &mdev->dev;
    > diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
    > index 0770410ded2a..7b47890c34e7 100644
    > --- a/drivers/vfio/mdev/mdev_private.h
    > +++ b/drivers/vfio/mdev/mdev_private.h
    > @@ -11,6 +11,7 @@
    > #define MDEV_PRIVATE_H
    >
    > #include <linux/vfio_mdev_ops.h>
    > +#include <linux/virtio_mdev_ops.h>
    >
    > int mdev_bus_register(void);
    > void mdev_bus_unregister(void);
    > @@ -38,6 +39,7 @@ struct mdev_device {
    > u16 class_id;
    > union {
    > const struct vfio_mdev_device_ops *vfio_ops;
    > + const struct virtio_mdev_device_ops *virtio_ops;
    > };
    > };
    >
    > diff --git a/include/linux/mdev.h b/include/linux/mdev.h
    > index 4625f1a11014..9b69b0bbebfd 100644
    > --- a/include/linux/mdev.h
    > +++ b/include/linux/mdev.h
    > @@ -17,6 +17,7 @@
    >
    > struct mdev_device;
    > struct vfio_mdev_device_ops;
    > +struct virtio_mdev_device_ops;
    >
    > /*
    > * Called by the parent device driver to set the device which represents
    > @@ -112,6 +113,10 @@ void mdev_set_class(struct mdev_device *mdev, u16 id);
    > void mdev_set_vfio_ops(struct mdev_device *mdev,
    > const struct vfio_mdev_device_ops *vfio_ops);
    > const struct vfio_mdev_device_ops *mdev_get_vfio_ops(struct mdev_device *mdev);
    > +void mdev_set_virtio_ops(struct mdev_device *mdev,
    > + const struct virtio_mdev_device_ops *virtio_ops);
    > +const struct virtio_mdev_device_ops *
    > +mdev_get_virtio_ops(struct mdev_device *mdev);
    >
    > extern struct bus_type mdev_bus_type;
    >
    > @@ -127,6 +132,7 @@ struct mdev_device *mdev_from_dev(struct device *dev);
    >
    > enum {
    > MDEV_CLASS_ID_VFIO = 1,
    > + MDEV_CLASS_ID_VIRTIO = 2,
    > /* New entries must be added here */
    > };
    >
    > diff --git a/include/linux/virtio_mdev_ops.h b/include/linux/virtio_mdev_ops.h
    > new file mode 100644
    > index 000000000000..d417b41f2845
    > --- /dev/null
    > +++ b/include/linux/virtio_mdev_ops.h
    > @@ -0,0 +1,159 @@
    > +/* 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_F_VERSION_1 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 for virtio/vhost drivers.
    > + *
    > + * The device ops that is supported by VIRTIO_MDEV_F_VERSION_1, the
    > + * callbacks are mandatory unless explicity mentioned.
    > + *
    > + * @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 interrupt callback 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 virtio 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_vq_num_max: Get the max size of virtqueue
    > + * @mdev: mediated device
    > + * Returns u16: max size of virtqueue
    > + * @get_device_id: Get virtio device id
    > + * @mdev: mediated device
    > + * Returns u32: virtio device id
    > + * @get_vendor_id: Get id for the vendor that provides this device
    > + * @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 configuration 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 configuration 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_mdev_features: Get a set of bits that demonstrate
    > + * thecapability of the mdev device. New
    > + * features bits must be added when
    > + * introducing new device ops.
    > + * @mdev: mediated device
    > + * Returns the mdev features (API) support by
    > + * the device.
    > + * @get_generation: Get device config generaton (optionally)
    > + * @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);
    > +
    > + /* Virtio 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_vq_num_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);

    Hi Jason

    Is it possible to make set_status() return an u8 or bool, because this
    may fail in real hardware. Without a returned code, I am not sure 
    whether it is a good idea to set the status | NEED_RESET when fail.

    Thanks,
    BR
    Zhu Lingshan
    > + 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);
    > + u32 (*get_generation)(struct mdev_device *mdev);
    > +
    > + /* Mdev device ops */
    > + u64 (*get_mdev_features)(struct mdev_device *mdev);
    > +};
    > +
    > +void mdev_set_virtio_ops(struct mdev_device *mdev,
    > + const struct virtio_mdev_device_ops *virtio_ops);
    > +
    > +#endif

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      Last update: 2019-10-29 08:43    [W:6.749 / U:0.712 seconds]
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