xref: /netbsd/sys/dev/pci/virtioreg.h (revision 601987ca)
1 /*	$NetBSD: virtioreg.h,v 1.12 2023/03/29 09:45:05 riastradh Exp $	*/
2 
3 /*
4  * Copyright (c) 2010 Minoura Makoto.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  */
27 
28 /*
29  * Part of the file derived from `Virtio PCI Card Specification v0.8.6 DRAFT'
30  * Appendix A.
31  */
32 /* An interface for efficient virtio implementation.
33  *
34  * This header is BSD licensed so anyone can use the definitions
35  * to implement compatible drivers/servers.
36  *
37  * Copyright 2007, 2009, IBM Corporation
38  * All rights reserved.
39  *
40  * Redistribution and use in source and binary forms, with or without
41  * modification, are permitted provided that the following conditions
42  * are met:
43  * 1. Redistributions of source code must retain the above copyright
44  *    notice, this list of conditions and the following disclaimer.
45  * 2. Redistributions in binary form must reproduce the above copyright
46  *    notice, this list of conditions and the following disclaimer in the
47  *    documentation and/or other materials provided with the distribution.
48  * 3. Neither the name of IBM nor the names of its contributors
49  *    may be used to endorse or promote products derived from this software
50  *    without specific prior written permission.
51  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
52  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
53  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
54  * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
55  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
56  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
57  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
58  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
59  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
60  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
61  * SUCH DAMAGE.
62  */
63 
64 
65 #ifndef _DEV_PCI_VIRTIOREG_H_
66 #define	_DEV_PCI_VIRTIOREG_H_
67 
68 #include <sys/types.h>
69 
70 /* Virtio product id (all subsystems) */
71 #define VIRTIO_DEVICE_ID_NETWORK	 1
72 #define VIRTIO_DEVICE_ID_BLOCK		 2
73 #define VIRTIO_DEVICE_ID_CONSOLE	 3
74 #define VIRTIO_DEVICE_ID_ENTROPY	 4
75 #define VIRTIO_DEVICE_ID_BALLOON	 5
76 #define VIRTIO_DEVICE_ID_IOMEM		 6
77 #define VIRTIO_DEVICE_ID_RPMSG		 7
78 #define VIRTIO_DEVICE_ID_SCSI		 8
79 #define VIRTIO_DEVICE_ID_9P		 9
80 
81 /* common device/guest features */
82 #define  VIRTIO_F_NOTIFY_ON_EMPTY		__BIT(24)
83 #define  VIRTIO_F_RING_INDIRECT_DESC		__BIT(28)
84 #define  VIRTIO_F_RING_EVENT_IDX		__BIT(29)
85 #define  VIRTIO_F_BAD_FEATURE			__BIT(30)
86 #define  VIRTIO_F_VERSION_1			__BIT(32)
87 
88 /* common device status flags */
89 #define  VIRTIO_CONFIG_DEVICE_STATUS_RESET		  0
90 #define  VIRTIO_CONFIG_DEVICE_STATUS_ACK		  1
91 #define  VIRTIO_CONFIG_DEVICE_STATUS_DRIVER		  2
92 #define  VIRTIO_CONFIG_DEVICE_STATUS_DRIVER_OK		  4
93 #define  VIRTIO_CONFIG_DEVICE_STATUS_FEATURES_OK	  8
94 #define  VIRTIO_CONFIG_DEVICE_STATUS_DEVICE_NEEDS_RESET	 64
95 #define  VIRTIO_CONFIG_DEVICE_STATUS_FAILED		128
96 
97 /* common ISR status flags */
98 #define  VIRTIO_CONFIG_ISR_QUEUE_INTERRUPT	1
99 #define  VIRTIO_CONFIG_ISR_CONFIG_CHANGE	2
100 
101 /* common device/guest features */
102 #define VIRTIO_COMMON_FLAG_BITS			\
103         "\177\020"				\
104 	"b\x20" "V1\0"				\
105 	"b\x1e" "BAD_FEATURE\0"			\
106 	"b\x1d" "EVENT_IDX\0"			\
107 	"b\x1c" "INDIRECT_DESC\0"		\
108 	"b\x18" "NOTIFY_ON_EMPTY\0"
109 
110 
111 /*
112  * Virtqueue
113  */
114 
115 /* marks a buffer as continuing via the next field. */
116 #define VRING_DESC_F_NEXT       1
117 
118 /* marks a buffer as write-only (otherwise read-only). */
119 #define VRING_DESC_F_WRITE      2
120 
121 /* the buffer contains a list of buffer descriptors. */
122 #define VRING_DESC_F_INDIRECT	4
123 
124 
125 /*
126  * The Host uses this in used->flags to advise the Guest: don't kick me when
127  * you add a buffer.  It's unreliable, so it's simply an optimization.  Guest
128  * will still kick if it's out of buffers.
129  */
130 #define VRING_USED_F_NO_NOTIFY  1
131 
132 /*
133  * The Guest uses this in avail->flags to advise the Host: don't interrupt me
134  * when you consume a buffer.  It's unreliable, so it's simply an
135  * optimization.
136  */
137 #define VRING_AVAIL_F_NO_INTERRUPT      1
138 
139 
140 /* Virtio ring descriptors: 16 bytes.
141  * These can chain together via "next". */
142 struct vring_desc {
143         /* Address (guest-physical). */
144         uint64_t addr;
145         /* Length. */
146         uint32_t len;
147         /* The flags as indicated above. */
148         uint16_t flags;
149         /* We chain unused descriptors via this, too */
150         uint16_t next;
151 } __packed;
152 
153 struct vring_avail {
154         uint16_t flags;
155         uint16_t idx;
156         uint16_t ring[];
157 	/* trailed by uint16_t used_event when VIRTIO_F_RING_EVENT_IDX */
158 } __packed;
159 
160 /* u32 is used here for ids for padding reasons. */
161 struct vring_used_elem {
162         /* Index of start of used descriptor chain. */
163         uint32_t id;
164         /* Total length of the descriptor chain which was written to. */
165         uint32_t len;
166 } __packed;
167 
168 struct vring_used {
169         uint16_t flags;
170         uint16_t idx;
171         struct vring_used_elem ring[];
172 	/* trailed by uint16_t avail_event when VIRTIO_F_RING_EVENT_IDX */
173 } __packed;
174 
175 /* The standard layout for the ring is a continuous chunk of memory which
176  * looks like this.  We assume num is a power of 2.
177  *
178  * struct vring {
179  *      // The actual descriptors (16 bytes each)
180  *      struct vring_desc desc[num];
181  *
182  *      // A ring of available descriptor heads with free-running index.
183  *      __u16 avail_flags;
184  *      __u16 avail_idx;
185  *      __u16 available[num];
186  *
187  *      // Padding to the next align boundary.
188  *      char pad[];
189  *
190  *      // A ring of used descriptor heads with free-running index.
191  *      __u16 used_flags;
192  *      __u16 used_idx;
193  *      struct vring_used_elem used[num];
194  * };
195  * Note: for virtio PCI, align is 4096.
196  */
197 
198 #define VIRTIO_PAGE_SIZE	(4096)
199 
200 #endif /* _DEV_PCI_VIRTIOREG_H_ */
201