1 | /* SPDX-License-Identifier: MIT */ |
2 | /****************************************************************************** |
3 | * vscsiif.h |
4 | * |
5 | * Based on the blkif.h code. |
6 | * |
7 | * Copyright(c) FUJITSU Limited 2008. |
8 | */ |
9 | |
10 | #ifndef __XEN__PUBLIC_IO_SCSI_H__ |
11 | #define __XEN__PUBLIC_IO_SCSI_H__ |
12 | |
13 | #include "ring.h" |
14 | #include "../grant_table.h" |
15 | |
16 | /* |
17 | * Feature and Parameter Negotiation |
18 | * ================================= |
19 | * The two halves of a Xen pvSCSI driver utilize nodes within the XenStore to |
20 | * communicate capabilities and to negotiate operating parameters. This |
21 | * section enumerates these nodes which reside in the respective front and |
22 | * backend portions of the XenStore, following the XenBus convention. |
23 | * |
24 | * Any specified default value is in effect if the corresponding XenBus node |
25 | * is not present in the XenStore. |
26 | * |
27 | * XenStore nodes in sections marked "PRIVATE" are solely for use by the |
28 | * driver side whose XenBus tree contains them. |
29 | * |
30 | ***************************************************************************** |
31 | * Backend XenBus Nodes |
32 | ***************************************************************************** |
33 | * |
34 | *------------------ Backend Device Identification (PRIVATE) ------------------ |
35 | * |
36 | * p-devname |
37 | * Values: string |
38 | * |
39 | * A free string used to identify the physical device (e.g. a disk name). |
40 | * |
41 | * p-dev |
42 | * Values: string |
43 | * |
44 | * A string specifying the backend device: either a 4-tuple "h:c:t:l" |
45 | * (host, controller, target, lun, all integers), or a WWN (e.g. |
46 | * "naa.60014054ac780582:0"). |
47 | * |
48 | * v-dev |
49 | * Values: string |
50 | * |
51 | * A string specifying the frontend device in form of a 4-tuple "h:c:t:l" |
52 | * (host, controller, target, lun, all integers). |
53 | * |
54 | *--------------------------------- Features --------------------------------- |
55 | * |
56 | * feature-sg-grant |
57 | * Values: unsigned [VSCSIIF_SG_TABLESIZE...65535] |
58 | * Default Value: 0 |
59 | * |
60 | * Specifies the maximum number of scatter/gather elements in grant pages |
61 | * supported. If not set, the backend supports up to VSCSIIF_SG_TABLESIZE |
62 | * SG elements specified directly in the request. |
63 | * |
64 | ***************************************************************************** |
65 | * Frontend XenBus Nodes |
66 | ***************************************************************************** |
67 | * |
68 | *----------------------- Request Transport Parameters ----------------------- |
69 | * |
70 | * event-channel |
71 | * Values: unsigned |
72 | * |
73 | * The identifier of the Xen event channel used to signal activity |
74 | * in the ring buffer. |
75 | * |
76 | * ring-ref |
77 | * Values: unsigned |
78 | * |
79 | * The Xen grant reference granting permission for the backend to map |
80 | * the sole page in a single page sized ring buffer. |
81 | * |
82 | * protocol |
83 | * Values: string (XEN_IO_PROTO_ABI_*) |
84 | * Default Value: XEN_IO_PROTO_ABI_NATIVE |
85 | * |
86 | * The machine ABI rules governing the format of all ring request and |
87 | * response structures. |
88 | */ |
89 | |
90 | /* |
91 | * Xenstore format in practice |
92 | * =========================== |
93 | * |
94 | * The backend driver uses a single_host:many_devices notation to manage domU |
95 | * devices. Everything is stored in /local/domain/<backend_domid>/backend/vscsi/. |
96 | * The xenstore layout looks like this (dom0 is assumed to be the backend_domid): |
97 | * |
98 | * <domid>/<vhost>/feature-host = "0" |
99 | * <domid>/<vhost>/frontend = "/local/domain/<domid>/device/vscsi/0" |
100 | * <domid>/<vhost>/frontend-id = "<domid>" |
101 | * <domid>/<vhost>/online = "1" |
102 | * <domid>/<vhost>/state = "4" |
103 | * <domid>/<vhost>/vscsi-devs/dev-0/p-dev = "8:0:2:1" or "naa.wwn:lun" |
104 | * <domid>/<vhost>/vscsi-devs/dev-0/state = "4" |
105 | * <domid>/<vhost>/vscsi-devs/dev-0/v-dev = "0:0:0:0" |
106 | * <domid>/<vhost>/vscsi-devs/dev-1/p-dev = "8:0:2:2" |
107 | * <domid>/<vhost>/vscsi-devs/dev-1/state = "4" |
108 | * <domid>/<vhost>/vscsi-devs/dev-1/v-dev = "0:0:1:0" |
109 | * |
110 | * The frontend driver maintains its state in |
111 | * /local/domain/<domid>/device/vscsi/. |
112 | * |
113 | * <vhost>/backend = "/local/domain/0/backend/vscsi/<domid>/<vhost>" |
114 | * <vhost>/backend-id = "0" |
115 | * <vhost>/event-channel = "20" |
116 | * <vhost>/ring-ref = "43" |
117 | * <vhost>/state = "4" |
118 | * <vhost>/vscsi-devs/dev-0/state = "4" |
119 | * <vhost>/vscsi-devs/dev-1/state = "4" |
120 | * |
121 | * In addition to the entries for backend and frontend these flags are stored |
122 | * for the toolstack: |
123 | * |
124 | * <domid>/<vhost>/vscsi-devs/dev-1/p-devname = "/dev/$device" |
125 | * <domid>/<vhost>/libxl_ctrl_index = "0" |
126 | * |
127 | * |
128 | * Backend/frontend protocol |
129 | * ========================= |
130 | * |
131 | * To create a vhost along with a device: |
132 | * <domid>/<vhost>/feature-host = "0" |
133 | * <domid>/<vhost>/frontend = "/local/domain/<domid>/device/vscsi/0" |
134 | * <domid>/<vhost>/frontend-id = "<domid>" |
135 | * <domid>/<vhost>/online = "1" |
136 | * <domid>/<vhost>/state = "1" |
137 | * <domid>/<vhost>/vscsi-devs/dev-0/p-dev = "8:0:2:1" |
138 | * <domid>/<vhost>/vscsi-devs/dev-0/state = "1" |
139 | * <domid>/<vhost>/vscsi-devs/dev-0/v-dev = "0:0:0:0" |
140 | * Wait for <domid>/<vhost>/state + <domid>/<vhost>/vscsi-devs/dev-0/state become 4 |
141 | * |
142 | * To add another device to a vhost: |
143 | * <domid>/<vhost>/state = "7" |
144 | * <domid>/<vhost>/vscsi-devs/dev-1/p-dev = "8:0:2:2" |
145 | * <domid>/<vhost>/vscsi-devs/dev-1/state = "1" |
146 | * <domid>/<vhost>/vscsi-devs/dev-1/v-dev = "0:0:1:0" |
147 | * Wait for <domid>/<vhost>/state + <domid>/<vhost>/vscsi-devs/dev-1/state become 4 |
148 | * |
149 | * To remove a device from a vhost: |
150 | * <domid>/<vhost>/state = "7" |
151 | * <domid>/<vhost>/vscsi-devs/dev-1/state = "5" |
152 | * Wait for <domid>/<vhost>/state to become 4 |
153 | * Wait for <domid>/<vhost>/vscsi-devs/dev-1/state become 6 |
154 | * Remove <domid>/<vhost>/vscsi-devs/dev-1/{state,p-dev,v-dev,p-devname} |
155 | * Remove <domid>/<vhost>/vscsi-devs/dev-1/ |
156 | * |
157 | */ |
158 | |
159 | /* Requests from the frontend to the backend */ |
160 | |
161 | /* |
162 | * Request a SCSI operation specified via a CDB in vscsiif_request.cmnd. |
163 | * The target is specified via channel, id and lun. |
164 | * |
165 | * The operation to be performed is specified via a CDB in cmnd[], the length |
166 | * of the CDB is in cmd_len. sc_data_direction specifies the direction of data |
167 | * (to the device, from the device, or none at all). |
168 | * |
169 | * If data is to be transferred to or from the device the buffer(s) in the |
170 | * guest memory is/are specified via one or multiple scsiif_request_segment |
171 | * descriptors each specifying a memory page via a grant_ref_t, a offset into |
172 | * the page and the length of the area in that page. All scsiif_request_segment |
173 | * areas concatenated form the resulting data buffer used by the operation. |
174 | * If the number of scsiif_request_segment areas is not too large (less than |
175 | * or equal VSCSIIF_SG_TABLESIZE) the areas can be specified directly in the |
176 | * seg[] array and the number of valid scsiif_request_segment elements is to be |
177 | * set in nr_segments. |
178 | * |
179 | * If "feature-sg-grant" in the Xenstore is set it is possible to specify more |
180 | * than VSCSIIF_SG_TABLESIZE scsiif_request_segment elements via indirection. |
181 | * The maximum number of allowed scsiif_request_segment elements is the value |
182 | * of the "feature-sg-grant" entry from Xenstore. When using indirection the |
183 | * seg[] array doesn't contain specifications of the data buffers, but |
184 | * references to scsiif_request_segment arrays, which in turn reference the |
185 | * data buffers. While nr_segments holds the number of populated seg[] entries |
186 | * (plus the set VSCSIIF_SG_GRANT bit), the number of scsiif_request_segment |
187 | * elements referencing the target data buffers is calculated from the lengths |
188 | * of the seg[] elements (the sum of all valid seg[].length divided by the |
189 | * size of one scsiif_request_segment structure). The frontend may use a mix of |
190 | * direct and indirect requests. |
191 | */ |
192 | #define VSCSIIF_ACT_SCSI_CDB 1 |
193 | |
194 | /* |
195 | * Request abort of a running operation for the specified target given by |
196 | * channel, id, lun and the operation's rqid in ref_rqid. |
197 | */ |
198 | #define VSCSIIF_ACT_SCSI_ABORT 2 |
199 | |
200 | /* |
201 | * Request a device reset of the specified target (channel and id). |
202 | */ |
203 | #define VSCSIIF_ACT_SCSI_RESET 3 |
204 | |
205 | /* |
206 | * Preset scatter/gather elements for a following request. Deprecated. |
207 | * Keeping the define only to avoid usage of the value "4" for other actions. |
208 | */ |
209 | #define VSCSIIF_ACT_SCSI_SG_PRESET 4 |
210 | |
211 | /* |
212 | * Maximum scatter/gather segments per request. |
213 | * |
214 | * Considering balance between allocating at least 16 "vscsiif_request" |
215 | * structures on one page (4096 bytes) and the number of scatter/gather |
216 | * elements needed, we decided to use 26 as a magic number. |
217 | * |
218 | * If "feature-sg-grant" is set, more scatter/gather elements can be specified |
219 | * by placing them in one or more (up to VSCSIIF_SG_TABLESIZE) granted pages. |
220 | * In this case the vscsiif_request seg elements don't contain references to |
221 | * the user data, but to the SG elements referencing the user data. |
222 | */ |
223 | #define VSCSIIF_SG_TABLESIZE 26 |
224 | |
225 | /* |
226 | * based on Linux kernel 2.6.18, still valid |
227 | * |
228 | * Changing these values requires support of multiple protocols via the rings |
229 | * as "old clients" will blindly use these values and the resulting structure |
230 | * sizes. |
231 | */ |
232 | #define VSCSIIF_MAX_COMMAND_SIZE 16 |
233 | #define VSCSIIF_SENSE_BUFFERSIZE 96 |
234 | #define VSCSIIF_PAGE_SIZE 4096 |
235 | |
236 | struct scsiif_request_segment { |
237 | grant_ref_t gref; |
238 | uint16_t offset; |
239 | uint16_t length; |
240 | }; |
241 | |
242 | #define VSCSIIF_SG_PER_PAGE (VSCSIIF_PAGE_SIZE / \ |
243 | sizeof(struct scsiif_request_segment)) |
244 | |
245 | /* Size of one request is 252 bytes */ |
246 | struct vscsiif_request { |
247 | uint16_t rqid; /* private guest value, echoed in resp */ |
248 | uint8_t act; /* command between backend and frontend */ |
249 | uint8_t cmd_len; /* valid CDB bytes */ |
250 | |
251 | uint8_t cmnd[VSCSIIF_MAX_COMMAND_SIZE]; /* the CDB */ |
252 | uint16_t timeout_per_command; /* deprecated */ |
253 | uint16_t channel, id, lun; /* (virtual) device specification */ |
254 | uint16_t ref_rqid; /* command abort reference */ |
255 | uint8_t sc_data_direction; /* for DMA_TO_DEVICE(1) |
256 | DMA_FROM_DEVICE(2) |
257 | DMA_NONE(3) requests */ |
258 | uint8_t nr_segments; /* Number of pieces of scatter-gather */ |
259 | /* |
260 | * flag in nr_segments: SG elements via grant page |
261 | * |
262 | * If VSCSIIF_SG_GRANT is set, the low 7 bits of nr_segments specify the number |
263 | * of grant pages containing SG elements. Usable if "feature-sg-grant" set. |
264 | */ |
265 | #define VSCSIIF_SG_GRANT 0x80 |
266 | |
267 | struct scsiif_request_segment seg[VSCSIIF_SG_TABLESIZE]; |
268 | uint32_t reserved[3]; |
269 | }; |
270 | |
271 | /* Size of one response is 252 bytes */ |
272 | struct vscsiif_response { |
273 | uint16_t rqid; /* identifies request */ |
274 | uint8_t padding; |
275 | uint8_t sense_len; |
276 | uint8_t sense_buffer[VSCSIIF_SENSE_BUFFERSIZE]; |
277 | int32_t rslt; |
278 | uint32_t residual_len; /* request bufflen - |
279 | return the value from physical device */ |
280 | uint32_t reserved[36]; |
281 | }; |
282 | |
283 | /* SCSI I/O status from vscsiif_response->rslt */ |
284 | #define XEN_VSCSIIF_RSLT_STATUS(x) ((x) & 0x00ff) |
285 | |
286 | /* Host I/O status from vscsiif_response->rslt */ |
287 | #define XEN_VSCSIIF_RSLT_HOST(x) (((x) & 0x00ff0000) >> 16) |
288 | #define XEN_VSCSIIF_RSLT_HOST_OK 0 |
289 | /* Couldn't connect before timeout */ |
290 | #define XEN_VSCSIIF_RSLT_HOST_NO_CONNECT 1 |
291 | /* Bus busy through timeout */ |
292 | #define XEN_VSCSIIF_RSLT_HOST_BUS_BUSY 2 |
293 | /* Timed out for other reason */ |
294 | #define XEN_VSCSIIF_RSLT_HOST_TIME_OUT 3 |
295 | /* Bad target */ |
296 | #define XEN_VSCSIIF_RSLT_HOST_BAD_TARGET 4 |
297 | /* Abort for some other reason */ |
298 | #define XEN_VSCSIIF_RSLT_HOST_ABORT 5 |
299 | /* Parity error */ |
300 | #define XEN_VSCSIIF_RSLT_HOST_PARITY 6 |
301 | /* Internal error */ |
302 | #define XEN_VSCSIIF_RSLT_HOST_ERROR 7 |
303 | /* Reset by somebody */ |
304 | #define XEN_VSCSIIF_RSLT_HOST_RESET 8 |
305 | /* Unexpected interrupt */ |
306 | #define XEN_VSCSIIF_RSLT_HOST_BAD_INTR 9 |
307 | /* Force command past mid-layer */ |
308 | #define XEN_VSCSIIF_RSLT_HOST_PASSTHROUGH 10 |
309 | /* Retry requested */ |
310 | #define XEN_VSCSIIF_RSLT_HOST_SOFT_ERROR 11 |
311 | /* Hidden retry requested */ |
312 | #define XEN_VSCSIIF_RSLT_HOST_IMM_RETRY 12 |
313 | /* Requeue command requested */ |
314 | #define XEN_VSCSIIF_RSLT_HOST_REQUEUE 13 |
315 | /* Transport error disrupted I/O */ |
316 | #define XEN_VSCSIIF_RSLT_HOST_TRANSPORT_DISRUPTED 14 |
317 | /* Transport class fastfailed */ |
318 | #define XEN_VSCSIIF_RSLT_HOST_TRANSPORT_FAILFAST 15 |
319 | /* Permanent target failure */ |
320 | #define XEN_VSCSIIF_RSLT_HOST_TARGET_FAILURE 16 |
321 | /* Permanent nexus failure on path */ |
322 | #define XEN_VSCSIIF_RSLT_HOST_NEXUS_FAILURE 17 |
323 | /* Space allocation on device failed */ |
324 | #define XEN_VSCSIIF_RSLT_HOST_ALLOC_FAILURE 18 |
325 | /* Medium error */ |
326 | #define XEN_VSCSIIF_RSLT_HOST_MEDIUM_ERROR 19 |
327 | /* Transport marginal errors */ |
328 | #define XEN_VSCSIIF_RSLT_HOST_TRANSPORT_MARGINAL 20 |
329 | |
330 | /* Result values of reset operations */ |
331 | #define XEN_VSCSIIF_RSLT_RESET_SUCCESS 0x2002 |
332 | #define XEN_VSCSIIF_RSLT_RESET_FAILED 0x2003 |
333 | |
334 | DEFINE_RING_TYPES(vscsiif, struct vscsiif_request, struct vscsiif_response); |
335 | |
336 | |
337 | #endif /*__XEN__PUBLIC_IO_SCSI_H__*/ |
338 | |