[PATCH V4 4/6] mdev: introduce virtio device and its device ops
Jason Wang
jasowang at redhat.com
Fri Oct 18 10:55:02 UTC 2019
On 2019/10/18 下午5:46, Cornelia Huck wrote:
> On Thu, 17 Oct 2019 18:48:34 +0800
> Jason Wang <jasowang at 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 at redhat.com>
>> ---
>> drivers/vfio/mdev/mdev_core.c | 12 +++
>> include/linux/mdev.h | 4 +
>> include/linux/virtio_mdev.h | 151 ++++++++++++++++++++++++++++++++++
>> 3 files changed, 167 insertions(+)
>> create mode 100644 include/linux/virtio_mdev.h
>>
>> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
>> index d0f3113c8071..5834f6b7c7a5 100644
>> --- a/drivers/vfio/mdev/mdev_core.c
>> +++ b/drivers/vfio/mdev/mdev_core.c
>> @@ -57,6 +57,18 @@ void mdev_set_vfio_ops(struct mdev_device *mdev,
>> }
>> EXPORT_SYMBOL(mdev_set_vfio_ops);
>>
>> +/* Specify the virtio device ops for the mdev device, this
>> + * must be called during create() callback for virtio mdev device.
>> + */
> Change this as for the vfio comment (last patch?)
Ok.
>
>> +void mdev_set_virtio_ops(struct mdev_device *mdev,
>> + const struct virtio_mdev_device_ops *virtio_ops)
>> +{
>> + BUG_ON(mdev->class_id);
> s/BUG_ON/WARN_ON/
Yes.
>
>> + mdev->class_id = MDEV_CLASS_ID_VIRTIO;
>> + mdev->device_ops = virtio_ops;
>> +}
>> +EXPORT_SYMBOL(mdev_set_virtio_ops);
>> +
>> const void *mdev_get_dev_ops(struct mdev_device *mdev)
>> {
>> return mdev->device_ops;
> (...)
>
>> diff --git a/include/linux/virtio_mdev.h b/include/linux/virtio_mdev.h
>> new file mode 100644
>> index 000000000000..b965b50f9b24
>> --- /dev/null
>> +++ b/include/linux/virtio_mdev.h
>> @@ -0,0 +1,151 @@
>> +/* 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_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 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)
> Probably dumb question (have not read the next patches yet): Is this
> agnostic regarding split or packed queues?
Yes, it is to and to be more obvious, I use the terminology from recent
spec.
>
>> + * @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
> s/get_features/set_features/
Will fix.
>
>> + * @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 virtio vendor id
>> + * @mdev: mediated device
>> + * Returns u32: virtio vendor id
> How is the vendor id defined? As for normal virtio-pci devices?
The vendor that provides this device. So something like this
I notice that MMIO also had this so it looks to me it's not pci specific.
>
>> + * @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 the feature of virtio mdev device
>> + * @mdev: mediated device
>> + * Returns the mdev features (API) support by
>> + * the device.
> What kind of 'features' are supposed to go in there? Are these bits,
> like you defined for VIRTIO_MDEV_F_VERSION_1 above?
It's the API or mdev features other than virtio features. It could be
used by driver to determine the capability of the mdev device. Besides
_F_VERSION_1, we may add dirty page tracking etc which means we need new
device ops.
>
>> + * @get_generation: Get device generaton
>> + * @mdev: mediated device
>> + * Returns u32: device generation
> Is that callback mandatory?
I think so, it's hard to emulate that completely in virtio-mdev transport.
Thanks
>
>> + */
>> +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_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);
>> + 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);
>> + u64 (*get_mdev_features)(struct mdev_device *mdev);
>> + u32 (*get_generation)(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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