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

From: Jason Wang <[email-masked]>
Date: Wed, 6 Nov 2019 21:35:29 +0800

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

Reviewed-by: Cornelia Huck <[email-masked]>
Signed-off-by: Jason Wang <[email-masked]>
---
 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" <[email-masked]>
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 <[email-masked]>
+ */
+#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