virtio.h revision 227652 
1/*
2 * This header is BSD licensed so anyone can use the definitions to implement
3 * compatible drivers/servers.
4 *
5 * $FreeBSD: head/sys/dev/virtio/virtio.h 227652 2011-11-18 05:43:43Z grehan $
6 */
7
8#ifndef _VIRTIO_H_
9#define _VIRTIO_H_
10
11#include <sys/types.h>
12
13struct vq_alloc_info;
14
15/* VirtIO device IDs. */
16#define VIRTIO_ID_NETWORK	0x01
17#define VIRTIO_ID_BLOCK		0x02
18#define VIRTIO_ID_CONSOLE	0x03
19#define VIRTIO_ID_ENTROPY	0x04
20#define VIRTIO_ID_BALLOON	0x05
21#define VIRTIO_ID_IOMEMORY	0x06
22#define VIRTIO_ID_9P		0x09
23
24/* Status byte for guest to report progress. */
25#define VIRTIO_CONFIG_STATUS_RESET	0x00
26#define VIRTIO_CONFIG_STATUS_ACK	0x01
27#define VIRTIO_CONFIG_STATUS_DRIVER	0x02
28#define VIRTIO_CONFIG_STATUS_DRIVER_OK	0x04
29#define VIRTIO_CONFIG_STATUS_FAILED	0x80
30
31/*
32 * Generate interrupt when the virtqueue ring is
33 * completely used, even if we've suppressed them.
34 */
35#define VIRTIO_F_NOTIFY_ON_EMPTY (1 << 24)
36
37/*
38 * The guest should never negotiate this feature; it
39 * is used to detect faulty drivers.
40 */
41#define VIRTIO_F_BAD_FEATURE (1 << 30)
42
43/*
44 * Some VirtIO feature bits (currently bits 28 through 31) are
45 * reserved for the transport being used (eg. virtio_ring), the
46 * rest are per-device feature bits.
47 */
48#define VIRTIO_TRANSPORT_F_START	28
49#define VIRTIO_TRANSPORT_F_END		32
50
51/*
52 * Maximum number of virtqueues per device.
53 */
54#define VIRTIO_MAX_VIRTQUEUES 8
55
56/*
57 * Each virtqueue indirect descriptor list must be physically contiguous.
58 * To allow us to malloc(9) each list individually, limit the number
59 * supported to what will fit in one page. With 4KB pages, this is a limit
60 * of 256 descriptors. If there is ever a need for more, we can switch to
61 * contigmalloc(9) for the larger allocations, similar to what
62 * bus_dmamem_alloc(9) does.
63 *
64 * Note the sizeof(struct vring_desc) is 16 bytes.
65 */
66#define VIRTIO_MAX_INDIRECT ((int) (PAGE_SIZE / 16))
67
68/*
69 * VirtIO instance variables indices.
70 */
71#define VIRTIO_IVAR_DEVTYPE		1
72#define VIRTIO_IVAR_FEATURE_DESC	2
73
74struct virtio_feature_desc {
75	uint64_t	 vfd_val;
76	char		*vfd_str;
77};
78
79const char *virtio_device_name(uint16_t devid);
80int	 virtio_get_device_type(device_t dev);
81void	 virtio_set_feature_desc(device_t dev,
82	     struct virtio_feature_desc *feature_desc);
83void	 virtio_describe(device_t dev, const char *msg,
84	     uint64_t features, struct virtio_feature_desc *feature_desc);
85
86/*
87 * VirtIO Bus Methods.
88 */
89uint64_t virtio_negotiate_features(device_t dev, uint64_t child_features);
90int	 virtio_alloc_virtqueues(device_t dev, int flags, int nvqs,
91	     struct vq_alloc_info *info);
92int	 virtio_setup_intr(device_t dev, enum intr_type type);
93int	 virtio_with_feature(device_t dev, uint64_t feature);
94void	 virtio_stop(device_t dev);
95int	 virtio_reinit(device_t dev, uint64_t features);
96void	 virtio_reinit_complete(device_t dev);
97
98/*
99 * Read/write a variable amount from the device specific (ie, network)
100 * configuration region. This region is encoded in the same endian as
101 * the guest.
102 */
103void	 virtio_read_device_config(device_t dev, bus_size_t offset,
104	     void *dst, int length);
105void	 virtio_write_device_config(device_t dev, bus_size_t offset,
106	     void *src, int length);
107
108/* Inlined device specific read/write functions for common lengths. */
109#define VIRTIO_RDWR_DEVICE_CONFIG(size, type)				\
110static inline type							\
111__CONCAT(virtio_read_dev_config_,size)(device_t dev,			\
112    bus_size_t offset)							\
113{									\
114	type val;							\
115	virtio_read_device_config(dev, offset, &val, sizeof(type));	\
116	return (val);							\
117}									\
118									\
119static inline void							\
120__CONCAT(virtio_write_dev_config_,size)(device_t dev,			\
121    bus_size_t offset, type val)					\
122{									\
123	virtio_write_device_config(dev, offset, &val, sizeof(type));	\
124}
125
126VIRTIO_RDWR_DEVICE_CONFIG(1, uint8_t);
127VIRTIO_RDWR_DEVICE_CONFIG(2, uint16_t);
128VIRTIO_RDWR_DEVICE_CONFIG(4, uint32_t);
129
130#endif /* _VIRTIO_H_ */
131