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1/* SPDX-License-Identifier: MIT */2/******************************************************************************3 * vscsiif.h4 *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 Negotiation18 * =================================19 * The two halves of a Xen pvSCSI driver utilize nodes within the XenStore to20 * communicate capabilities and to negotiate operating parameters. This21 * section enumerates these nodes which reside in the respective front and22 * backend portions of the XenStore, following the XenBus convention.23 *24 * Any specified default value is in effect if the corresponding XenBus node25 * is not present in the XenStore.26 *27 * XenStore nodes in sections marked "PRIVATE" are solely for use by the28 * driver side whose XenBus tree contains them.29 *30 *****************************************************************************31 * Backend XenBus Nodes32 *****************************************************************************33 *34 *------------------ Backend Device Identification (PRIVATE) ------------------35 *36 * p-devname37 * Values: string38 *39 * A free string used to identify the physical device (e.g. a disk name).40 *41 * p-dev42 * Values: string43 *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-dev49 * Values: string50 *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-grant57 * Values: unsigned [VSCSIIF_SG_TABLESIZE...65535]58 * Default Value: 059 *60 * Specifies the maximum number of scatter/gather elements in grant pages61 * supported. If not set, the backend supports up to VSCSIIF_SG_TABLESIZE62 * SG elements specified directly in the request.63 *64 *****************************************************************************65 * Frontend XenBus Nodes66 *****************************************************************************67 *68 *----------------------- Request Transport Parameters -----------------------69 *70 * event-channel71 * Values: unsigned72 *73 * The identifier of the Xen event channel used to signal activity74 * in the ring buffer.75 *76 * ring-ref77 * Values: unsigned78 *79 * The Xen grant reference granting permission for the backend to map80 * the sole page in a single page sized ring buffer.81 *82 * protocol83 * Values: string (XEN_IO_PROTO_ABI_*)84 * Default Value: XEN_IO_PROTO_ABI_NATIVE85 *86 * The machine ABI rules governing the format of all ring request and87 * response structures.88 */89 90/*91 * Xenstore format in practice92 * ===========================93 *94 * The backend driver uses a single_host:many_devices notation to manage domU95 * 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 in111 * /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 stored122 * 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 protocol129 * =========================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 4141 *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 4148 *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 4153 * Wait for <domid>/<vhost>/vscsi-devs/dev-1/state become 6154 * 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 length166 * of the CDB is in cmd_len. sc_data_direction specifies the direction of data167 * (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 the170 * guest memory is/are specified via one or multiple scsiif_request_segment171 * descriptors each specifying a memory page via a grant_ref_t, a offset into172 * the page and the length of the area in that page. All scsiif_request_segment173 * 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 than175 * or equal VSCSIIF_SG_TABLESIZE) the areas can be specified directly in the176 * seg[] array and the number of valid scsiif_request_segment elements is to be177 * set in nr_segments.178 *179 * If "feature-sg-grant" in the Xenstore is set it is possible to specify more180 * than VSCSIIF_SG_TABLESIZE scsiif_request_segment elements via indirection.181 * The maximum number of allowed scsiif_request_segment elements is the value182 * of the "feature-sg-grant" entry from Xenstore. When using indirection the183 * seg[] array doesn't contain specifications of the data buffers, but184 * references to scsiif_request_segment arrays, which in turn reference the185 * data buffers. While nr_segments holds the number of populated seg[] entries186 * (plus the set VSCSIIF_SG_GRANT bit), the number of scsiif_request_segment187 * elements referencing the target data buffers is calculated from the lengths188 * of the seg[] elements (the sum of all valid seg[].length divided by the189 * size of one scsiif_request_segment structure). The frontend may use a mix of190 * direct and indirect requests.191 */192#define VSCSIIF_ACT_SCSI_CDB 1193 194/*195 * Request abort of a running operation for the specified target given by196 * channel, id, lun and the operation's rqid in ref_rqid.197 */198#define VSCSIIF_ACT_SCSI_ABORT 2199 200/*201 * Request a device reset of the specified target (channel and id).202 */203#define VSCSIIF_ACT_SCSI_RESET 3204 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 4210 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/gather216 * 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 specified219 * 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 to221 * the user data, but to the SG elements referencing the user data.222 */223#define VSCSIIF_SG_TABLESIZE 26224 225/*226 * based on Linux kernel 2.6.18, still valid227 *228 * Changing these values requires support of multiple protocols via the rings229 * as "old clients" will blindly use these values and the resulting structure230 * sizes.231 */232#define VSCSIIF_MAX_COMMAND_SIZE 16233#define VSCSIIF_SENSE_BUFFERSIZE 96234#define VSCSIIF_PAGE_SIZE 4096235 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 page261 *262 * If VSCSIIF_SG_GRANT is set, the low 7 bits of nr_segments specify the number263 * of grant pages containing SG elements. Usable if "feature-sg-grant" set.264 */265#define VSCSIIF_SG_GRANT 0x80266 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 0289/* Couldn't connect before timeout */290#define XEN_VSCSIIF_RSLT_HOST_NO_CONNECT 1291/* Bus busy through timeout */292#define XEN_VSCSIIF_RSLT_HOST_BUS_BUSY 2293/* Timed out for other reason */294#define XEN_VSCSIIF_RSLT_HOST_TIME_OUT 3295/* Bad target */296#define XEN_VSCSIIF_RSLT_HOST_BAD_TARGET 4297/* Abort for some other reason */298#define XEN_VSCSIIF_RSLT_HOST_ABORT 5299/* Parity error */300#define XEN_VSCSIIF_RSLT_HOST_PARITY 6301/* Internal error */302#define XEN_VSCSIIF_RSLT_HOST_ERROR 7303/* Reset by somebody */304#define XEN_VSCSIIF_RSLT_HOST_RESET 8305/* Unexpected interrupt */306#define XEN_VSCSIIF_RSLT_HOST_BAD_INTR 9307/* Force command past mid-layer */308#define XEN_VSCSIIF_RSLT_HOST_PASSTHROUGH 10309/* Retry requested */310#define XEN_VSCSIIF_RSLT_HOST_SOFT_ERROR 11311/* Hidden retry requested */312#define XEN_VSCSIIF_RSLT_HOST_IMM_RETRY 12313/* Requeue command requested */314#define XEN_VSCSIIF_RSLT_HOST_REQUEUE 13315/* Transport error disrupted I/O */316#define XEN_VSCSIIF_RSLT_HOST_TRANSPORT_DISRUPTED 14317/* Transport class fastfailed */318#define XEN_VSCSIIF_RSLT_HOST_TRANSPORT_FAILFAST 15319/* Permanent target failure */320#define XEN_VSCSIIF_RSLT_HOST_TARGET_FAILURE 16321/* Permanent nexus failure on path */322#define XEN_VSCSIIF_RSLT_HOST_NEXUS_FAILURE 17323/* Space allocation on device failed */324#define XEN_VSCSIIF_RSLT_HOST_ALLOC_FAILURE 18325/* Medium error */326#define XEN_VSCSIIF_RSLT_HOST_MEDIUM_ERROR 19327/* Transport marginal errors */328#define XEN_VSCSIIF_RSLT_HOST_TRANSPORT_MARGINAL 20329 330/* Result values of reset operations */331#define XEN_VSCSIIF_RSLT_RESET_SUCCESS 0x2002332#define XEN_VSCSIIF_RSLT_RESET_FAILED 0x2003333 334DEFINE_RING_TYPES(vscsiif, struct vscsiif_request, struct vscsiif_response);335 336 337#endif /*__XEN__PUBLIC_IO_SCSI_H__*/338