xref: /freebsd/sys/dev/virtio/virtio.h (revision a10cee30c94cf5944826d2a495e9cdf339dfbcc8)
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  * $FreeBSD$
29  */
30 
31 #ifndef _VIRTIO_H_
32 #define _VIRTIO_H_
33 
34 struct vq_alloc_info;
35 
36 /* VirtIO device IDs. */
37 #define VIRTIO_ID_NETWORK	0x01
38 #define VIRTIO_ID_BLOCK		0x02
39 #define VIRTIO_ID_CONSOLE	0x03
40 #define VIRTIO_ID_ENTROPY	0x04
41 #define VIRTIO_ID_BALLOON	0x05
42 #define VIRTIO_ID_IOMEMORY	0x06
43 #define VIRTIO_ID_9P		0x09
44 
45 /* Status byte for guest to report progress. */
46 #define VIRTIO_CONFIG_STATUS_RESET	0x00
47 #define VIRTIO_CONFIG_STATUS_ACK	0x01
48 #define VIRTIO_CONFIG_STATUS_DRIVER	0x02
49 #define VIRTIO_CONFIG_STATUS_DRIVER_OK	0x04
50 #define VIRTIO_CONFIG_STATUS_FAILED	0x80
51 
52 /*
53  * Generate interrupt when the virtqueue ring is
54  * completely used, even if we've suppressed them.
55  */
56 #define VIRTIO_F_NOTIFY_ON_EMPTY (1 << 24)
57 
58 /*
59  * The guest should never negotiate this feature; it
60  * is used to detect faulty drivers.
61  */
62 #define VIRTIO_F_BAD_FEATURE (1 << 30)
63 
64 /*
65  * Some VirtIO feature bits (currently bits 28 through 31) are
66  * reserved for the transport being used (eg. virtio_ring), the
67  * rest are per-device feature bits.
68  */
69 #define VIRTIO_TRANSPORT_F_START	28
70 #define VIRTIO_TRANSPORT_F_END		32
71 
72 /*
73  * Maximum number of virtqueues per device.
74  */
75 #define VIRTIO_MAX_VIRTQUEUES 8
76 
77 /*
78  * Each virtqueue indirect descriptor list must be physically contiguous.
79  * To allow us to malloc(9) each list individually, limit the number
80  * supported to what will fit in one page. With 4KB pages, this is a limit
81  * of 256 descriptors. If there is ever a need for more, we can switch to
82  * contigmalloc(9) for the larger allocations, similar to what
83  * bus_dmamem_alloc(9) does.
84  *
85  * Note the sizeof(struct vring_desc) is 16 bytes.
86  */
87 #define VIRTIO_MAX_INDIRECT ((int) (PAGE_SIZE / 16))
88 
89 /*
90  * VirtIO instance variables indices.
91  */
92 #define VIRTIO_IVAR_DEVTYPE		1
93 #define VIRTIO_IVAR_FEATURE_DESC	2
94 #define VIRTIO_IVAR_VENDOR		3
95 #define VIRTIO_IVAR_DEVICE		4
96 #define VIRTIO_IVAR_SUBVENDOR		5
97 #define VIRTIO_IVAR_SUBDEVICE		6
98 
99 struct virtio_feature_desc {
100 	uint64_t	 vfd_val;
101 	char		*vfd_str;
102 };
103 
104 const char *virtio_device_name(uint16_t devid);
105 void	 virtio_describe(device_t dev, const char *msg,
106 	     uint64_t features, struct virtio_feature_desc *feature_desc);
107 
108 /*
109  * VirtIO Bus Methods.
110  */
111 void	 virtio_read_ivar(device_t dev, int ivar, uintptr_t *val);
112 void	 virtio_write_ivar(device_t dev, int ivar, uintptr_t val);
113 uint64_t virtio_negotiate_features(device_t dev, uint64_t child_features);
114 int	 virtio_alloc_virtqueues(device_t dev, int flags, int nvqs,
115 	     struct vq_alloc_info *info);
116 int	 virtio_setup_intr(device_t dev, enum intr_type type);
117 int	 virtio_with_feature(device_t dev, uint64_t feature);
118 void	 virtio_stop(device_t dev);
119 int	 virtio_reinit(device_t dev, uint64_t features);
120 void	 virtio_reinit_complete(device_t dev);
121 
122 /*
123  * Read/write a variable amount from the device specific (ie, network)
124  * configuration region. This region is encoded in the same endian as
125  * the guest.
126  */
127 void	 virtio_read_device_config(device_t dev, bus_size_t offset,
128 	     void *dst, int length);
129 void	 virtio_write_device_config(device_t dev, bus_size_t offset,
130 	     void *src, int length);
131 
132 /* Inlined device specific read/write functions for common lengths. */
133 #define VIRTIO_RDWR_DEVICE_CONFIG(size, type)				\
134 static inline type							\
135 __CONCAT(virtio_read_dev_config_,size)(device_t dev,			\
136     bus_size_t offset)							\
137 {									\
138 	type val;							\
139 	virtio_read_device_config(dev, offset, &val, sizeof(type));	\
140 	return (val);							\
141 }									\
142 									\
143 static inline void							\
144 __CONCAT(virtio_write_dev_config_,size)(device_t dev,			\
145     bus_size_t offset, type val)					\
146 {									\
147 	virtio_write_device_config(dev, offset, &val, sizeof(type));	\
148 }
149 
150 VIRTIO_RDWR_DEVICE_CONFIG(1, uint8_t);
151 VIRTIO_RDWR_DEVICE_CONFIG(2, uint16_t);
152 VIRTIO_RDWR_DEVICE_CONFIG(4, uint32_t);
153 
154 #undef VIRTIO_RDWR_DEVICE_CONFIG
155 
156 #define VIRTIO_READ_IVAR(name, ivar)					\
157 static inline int							\
158 __CONCAT(virtio_get_,name)(device_t dev)				\
159 {									\
160 	uintptr_t val;							\
161 	virtio_read_ivar(dev, ivar, &val);				\
162 	return ((int) val);						\
163 }
164 
165 VIRTIO_READ_IVAR(device_type,	VIRTIO_IVAR_DEVTYPE);
166 VIRTIO_READ_IVAR(vendor,	VIRTIO_IVAR_VENDOR);
167 VIRTIO_READ_IVAR(device,	VIRTIO_IVAR_DEVICE);
168 VIRTIO_READ_IVAR(subvendor,	VIRTIO_IVAR_SUBVENDOR);
169 VIRTIO_READ_IVAR(subdevice,	VIRTIO_IVAR_SUBDEVICE);
170 
171 #undef VIRTIO_READ_IVAR
172 
173 #define VIRTIO_WRITE_IVAR(name, ivar)					\
174 static inline void							\
175 __CONCAT(virtio_set_,name)(device_t dev, void *val)			\
176 {									\
177 	virtio_write_ivar(dev, ivar, (uintptr_t) val);			\
178 }
179 
180 VIRTIO_WRITE_IVAR(feature_desc,	VIRTIO_IVAR_FEATURE_DESC);
181 
182 #undef VIRTIO_WRITE_IVAR
183 
184 #endif /* _VIRTIO_H_ */
185