vscsiif.h (12815B)
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 236struct 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 */ 246struct 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 */ 272struct 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 334DEFINE_RING_TYPES(vscsiif, struct vscsiif_request, struct vscsiif_response); 335 336 337#endif /*__XEN__PUBLIC_IO_SCSI_H__*/