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:jasow...@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<jasow...@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<jasow...@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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