Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging
[qemu.git] / pc-bios / s390-ccw / virtio.h
1 /*
2 * Virtio driver bits
3 *
4 * Copyright (c) 2013 Alexander Graf <agraf@suse.de>
5 *
6 * This work is licensed under the terms of the GNU GPL, version 2 or (at
7 * your option) any later version. See the COPYING file in the top-level
8 * directory.
9 */
10
11 #ifndef VIRTIO_H
12 #define VIRTIO_H
13
14 #include "s390-ccw.h"
15
16 /* Status byte for guest to report progress, and synchronize features. */
17 /* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */
18 #define VIRTIO_CONFIG_S_ACKNOWLEDGE 1
19 /* We have found a driver for the device. */
20 #define VIRTIO_CONFIG_S_DRIVER 2
21 /* Driver has used its parts of the config, and is happy */
22 #define VIRTIO_CONFIG_S_DRIVER_OK 4
23 /* We've given up on this device. */
24 #define VIRTIO_CONFIG_S_FAILED 0x80
25
26 enum virtio_dev_type {
27 VIRTIO_ID_NET = 1,
28 VIRTIO_ID_BLOCK = 2,
29 VIRTIO_ID_CONSOLE = 3,
30 VIRTIO_ID_BALLOON = 5,
31 };
32
33 struct virtio_dev_header {
34 enum virtio_dev_type type : 8;
35 u8 num_vq;
36 u8 feature_len;
37 u8 config_len;
38 u8 status;
39 u8 vqconfig[];
40 } __attribute__((packed));
41
42 struct virtio_vqconfig {
43 u64 token;
44 u64 address;
45 u16 num;
46 u8 pad[6];
47 } __attribute__((packed));
48
49 struct vq_info_block {
50 u64 queue;
51 u32 align;
52 u16 index;
53 u16 num;
54 } __attribute__((packed));
55
56 struct vq_config_block {
57 u16 index;
58 u16 num;
59 } __attribute__((packed));
60
61 struct virtio_dev {
62 struct virtio_dev_header *header;
63 struct virtio_vqconfig *vqconfig;
64 char *host_features;
65 char *guest_features;
66 char *config;
67 };
68
69 #define KVM_S390_VIRTIO_RING_ALIGN 4096
70
71 #define VRING_USED_F_NO_NOTIFY 1
72
73 /* This marks a buffer as continuing via the next field. */
74 #define VRING_DESC_F_NEXT 1
75 /* This marks a buffer as write-only (otherwise read-only). */
76 #define VRING_DESC_F_WRITE 2
77 /* This means the buffer contains a list of buffer descriptors. */
78 #define VRING_DESC_F_INDIRECT 4
79
80 /* Internal flag to mark follow-up segments as such */
81 #define VRING_HIDDEN_IS_CHAIN 256
82
83 /* Virtio ring descriptors: 16 bytes. These can chain together via "next". */
84 struct vring_desc {
85 /* Address (guest-physical). */
86 u64 addr;
87 /* Length. */
88 u32 len;
89 /* The flags as indicated above. */
90 u16 flags;
91 /* We chain unused descriptors via this, too */
92 u16 next;
93 } __attribute__((packed));
94
95 struct vring_avail {
96 u16 flags;
97 u16 idx;
98 u16 ring[];
99 } __attribute__((packed));
100
101 /* u32 is used here for ids for padding reasons. */
102 struct vring_used_elem {
103 /* Index of start of used descriptor chain. */
104 u32 id;
105 /* Total length of the descriptor chain which was used (written to) */
106 u32 len;
107 } __attribute__((packed));
108
109 struct vring_used {
110 u16 flags;
111 u16 idx;
112 struct vring_used_elem ring[];
113 } __attribute__((packed));
114
115 struct vring {
116 unsigned int num;
117 int next_idx;
118 int used_idx;
119 struct vring_desc *desc;
120 struct vring_avail *avail;
121 struct vring_used *used;
122 struct subchannel_id schid;
123 };
124
125
126 /***********************************************
127 * Virtio block *
128 ***********************************************/
129
130 /*
131 * Command types
132 *
133 * Usage is a bit tricky as some bits are used as flags and some are not.
134 *
135 * Rules:
136 * VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
137 * VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own
138 * and may not be combined with any of the other flags.
139 */
140
141 /* These two define direction. */
142 #define VIRTIO_BLK_T_IN 0
143 #define VIRTIO_BLK_T_OUT 1
144
145 /* This bit says it's a scsi command, not an actual read or write. */
146 #define VIRTIO_BLK_T_SCSI_CMD 2
147
148 /* Cache flush command */
149 #define VIRTIO_BLK_T_FLUSH 4
150
151 /* Barrier before this op. */
152 #define VIRTIO_BLK_T_BARRIER 0x80000000
153
154 /* This is the first element of the read scatter-gather list. */
155 struct virtio_blk_outhdr {
156 /* VIRTIO_BLK_T* */
157 u32 type;
158 /* io priority. */
159 u32 ioprio;
160 /* Sector (ie. 512 byte offset) */
161 u64 sector;
162 };
163
164 #endif /* VIRTIO_H */