virtio.h revision 228301 
1/*-
2 * This header is BSD licensed so anyone can use the definitions to implement
3 * compatible drivers/servers.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of IBM nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD: head/sys/dev/virtio/virtio.h 228301 2011-12-06 06:28:32Z grehan $
29 */
30
31#ifndef _VIRTIO_H_
32#define _VIRTIO_H_
33
34#include <sys/types.h>
35
36struct vq_alloc_info;
37
38/* VirtIO device IDs. */
39#define VIRTIO_ID_NETWORK	0x01
40#define VIRTIO_ID_BLOCK		0x02
41#define VIRTIO_ID_CONSOLE	0x03
42#define VIRTIO_ID_ENTROPY	0x04
43#define VIRTIO_ID_BALLOON	0x05
44#define VIRTIO_ID_IOMEMORY	0x06
45#define VIRTIO_ID_9P		0x09
46
47/* Status byte for guest to report progress. */
48#define VIRTIO_CONFIG_STATUS_RESET	0x00
49#define VIRTIO_CONFIG_STATUS_ACK	0x01
50#define VIRTIO_CONFIG_STATUS_DRIVER	0x02
51#define VIRTIO_CONFIG_STATUS_DRIVER_OK	0x04
52#define VIRTIO_CONFIG_STATUS_FAILED	0x80
53
54/*
55 * Generate interrupt when the virtqueue ring is
56 * completely used, even if we've suppressed them.
57 */
58#define VIRTIO_F_NOTIFY_ON_EMPTY (1 << 24)
59
60/*
61 * The guest should never negotiate this feature; it
62 * is used to detect faulty drivers.
63 */
64#define VIRTIO_F_BAD_FEATURE (1 << 30)
65
66/*
67 * Some VirtIO feature bits (currently bits 28 through 31) are
68 * reserved for the transport being used (eg. virtio_ring), the
69 * rest are per-device feature bits.
70 */
71#define VIRTIO_TRANSPORT_F_START	28
72#define VIRTIO_TRANSPORT_F_END		32
73
74/*
75 * Maximum number of virtqueues per device.
76 */
77#define VIRTIO_MAX_VIRTQUEUES 8
78
79/*
80 * Each virtqueue indirect descriptor list must be physically contiguous.
81 * To allow us to malloc(9) each list individually, limit the number
82 * supported to what will fit in one page. With 4KB pages, this is a limit
83 * of 256 descriptors. If there is ever a need for more, we can switch to
84 * contigmalloc(9) for the larger allocations, similar to what
85 * bus_dmamem_alloc(9) does.
86 *
87 * Note the sizeof(struct vring_desc) is 16 bytes.
88 */
89#define VIRTIO_MAX_INDIRECT ((int) (PAGE_SIZE / 16))
90
91/*
92 * VirtIO instance variables indices.
93 */
94#define VIRTIO_IVAR_DEVTYPE		1
95#define VIRTIO_IVAR_FEATURE_DESC	2
96
97struct virtio_feature_desc {
98	uint64_t	 vfd_val;
99	char		*vfd_str;
100};
101
102const char *virtio_device_name(uint16_t devid);
103int	 virtio_get_device_type(device_t dev);
104void	 virtio_set_feature_desc(device_t dev,
105	     struct virtio_feature_desc *feature_desc);
106void	 virtio_describe(device_t dev, const char *msg,
107	     uint64_t features, struct virtio_feature_desc *feature_desc);
108
109/*
110 * VirtIO Bus Methods.
111 */
112uint64_t virtio_negotiate_features(device_t dev, uint64_t child_features);
113int	 virtio_alloc_virtqueues(device_t dev, int flags, int nvqs,
114	     struct vq_alloc_info *info);
115int	 virtio_setup_intr(device_t dev, enum intr_type type);
116int	 virtio_with_feature(device_t dev, uint64_t feature);
117void	 virtio_stop(device_t dev);
118int	 virtio_reinit(device_t dev, uint64_t features);
119void	 virtio_reinit_complete(device_t dev);
120
121/*
122 * Read/write a variable amount from the device specific (ie, network)
123 * configuration region. This region is encoded in the same endian as
124 * the guest.
125 */
126void	 virtio_read_device_config(device_t dev, bus_size_t offset,
127	     void *dst, int length);
128void	 virtio_write_device_config(device_t dev, bus_size_t offset,
129	     void *src, int length);
130
131/* Inlined device specific read/write functions for common lengths. */
132#define VIRTIO_RDWR_DEVICE_CONFIG(size, type)				\
133static inline type							\
134__CONCAT(virtio_read_dev_config_,size)(device_t dev,			\
135    bus_size_t offset)							\
136{									\
137	type val;							\
138	virtio_read_device_config(dev, offset, &val, sizeof(type));	\
139	return (val);							\
140}									\
141									\
142static inline void							\
143__CONCAT(virtio_write_dev_config_,size)(device_t dev,			\
144    bus_size_t offset, type val)					\
145{									\
146	virtio_write_device_config(dev, offset, &val, sizeof(type));	\
147}
148
149VIRTIO_RDWR_DEVICE_CONFIG(1, uint8_t);
150VIRTIO_RDWR_DEVICE_CONFIG(2, uint16_t);
151VIRTIO_RDWR_DEVICE_CONFIG(4, uint32_t);
152
153#endif /* _VIRTIO_H_ */
154