[PATCH V10 4/6] mdev: introduce virtio device and its device ops

Jason Wang
2019-11-06T13:41:12Z

This patch implements basic support for mdev driver that supports
virtio transport for kernel virtio driver.

Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
MAINTAINERS | 1 +
drivers/vfio/mdev/mdev_core.c | 21 +++++
drivers/vfio/mdev/mdev_private.h | 2 +
include/linux/mdev.h | 6 ++
include/linux/mdev_virtio_ops.h | 147 +++++++++++++++++++++++++++++++
5 files changed, 177 insertions(+)
create mode 100644 include/linux/mdev_virtio_ops.h

diff --git a/MAINTAINERS b/MAINTAINERS
index f661d13344d6..4997957443df 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17248,6 +17248,7 @@ F: include/linux/virtio*.h
F: include/uapi/linux/virtio_*.h
F: drivers/crypto/virtio/
F: mm/balloon_compaction.c
+F: include/linux/mdev_virtio_ops.h

VIRTIO BLOCK AND SCSI DRIVERS
M: "Michael S. Tsirkin" <mst@redhat.com>
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index 4e70f19ac145..c58253404ed5 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -78,6 +78,27 @@ const struct mdev_vfio_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 mdev_virtio_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 mdev_virtio_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 411227373625..2c74dd032409 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/mdev_vfio_ops.h>
+#include <linux/mdev_virtio_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 mdev_vfio_device_ops *vfio_ops;
+ const struct mdev_virtio_device_ops *virtio_ops;
};
};

diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 9e37506d1987..f3d75a60c2b5 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -17,6 +17,7 @@

struct mdev_device;
struct mdev_vfio_device_ops;
+struct mdev_virtio_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 mdev_vfio_device_ops *vfio_ops);
const struct mdev_vfio_device_ops *mdev_get_vfio_ops(struct mdev_device *mdev);
+void mdev_set_virtio_ops(struct mdev_device *mdev,
+ const struct mdev_virtio_device_ops *virtio_ops);
+const struct mdev_virtio_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/mdev_virtio_ops.h b/include/linux/mdev_virtio_ops.h
new file mode 100644
index 000000000000..8951331c6629
--- /dev/null
+++ b/include/linux/mdev_virtio_ops.h
@@ -0,0 +1,147 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Virtio mediated device driver
+ *
+ * Copyright 2019, Red Hat Corp.
+ * Author: Jason Wang <jasowang@redhat.com>
+ */
+#ifndef MDEV_VIRTIO_OPS_H
+#define MDEV_VIRTIO_OPS_H
+
+#include <linux/interrupt.h>
+#include <linux/mdev.h>
+#include <uapi/linux/vhost.h>
+
+#define VIRTIO_MDEV_DEVICE_API_STRING "virtio-mdev"
+
+struct virtio_mdev_callback {
+ irqreturn_t (*callback)(void *data);
+ void *private;
+};
+
+/**
+ * struct mdev_virtio_device_ops - Structure to be registered for each
+ * mdev device to register the device for virtio/vhost drivers.
+ *
+ * The callbacks are mandatory unless explicitly 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
+ * @set_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_generation: Get device config generaton (optional)
+ * @mdev: mediated device
+ * Returns u32: device generation
+ */
+struct mdev_virtio_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);
+ 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);
+};
+
+void mdev_set_virtio_ops(struct mdev_device *mdev,
+ const struct mdev_virtio_device_ops *virtio_ops);
+
+#endif
--
2.19.1