/****************************************************************************** * vscsiif.h * * Based on the blkif.h code. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to * deal in the Software without restriction, including without limitation the * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or * sell copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. * * Copyright(c) FUJITSU Limited 2008. */ #ifndef __XEN__PUBLIC_IO_SCSI_H__ #define __XEN__PUBLIC_IO_SCSI_H__ #include "ring.h" #include "../grant_table.h" /* * Feature and Parameter Negotiation * ================================= * The two halves of a Xen pvSCSI driver utilize nodes within the XenStore to * communicate capabilities and to negotiate operating parameters. This * section enumerates these nodes which reside in the respective front and * backend portions of the XenStore, following the XenBus convention. * * Any specified default value is in effect if the corresponding XenBus node * is not present in the XenStore. * * XenStore nodes in sections marked "PRIVATE" are solely for use by the * driver side whose XenBus tree contains them. * ***************************************************************************** * Backend XenBus Nodes ***************************************************************************** * *------------------ Backend Device Identification (PRIVATE) ------------------ * * p-devname * Values: string * * A free string used to identify the physical device (e.g. a disk name). * * p-dev * Values: string * * A string specifying the backend device: either a 4-tuple "h:c:t:l" * (host, controller, target, lun, all integers), or a WWN (e.g. * "naa.60014054ac780582"). * * v-dev * Values: string * * A string specifying the frontend device in form of a 4-tuple "h:c:t:l" * (host, controller, target, lun, all integers). * *--------------------------------- Features --------------------------------- * * feature-sg-grant * Values: unsigned [VSCSIIF_SG_TABLESIZE...65535] * Default Value: 0 * * Specifies the maximum number of scatter/gather elements in grant pages * supported. If not set, the backend supports up to VSCSIIF_SG_TABLESIZE * SG elements specified directly in the request. * ***************************************************************************** * Frontend XenBus Nodes ***************************************************************************** * *----------------------- Request Transport Parameters ----------------------- * * event-channel * Values: unsigned * * The identifier of the Xen event channel used to signal activity * in the ring buffer. * * ring-ref * Values: unsigned * * The Xen grant reference granting permission for the backend to map * the sole page in a single page sized ring buffer. * * protocol * Values: string (XEN_IO_PROTO_ABI_*) * Default Value: XEN_IO_PROTO_ABI_NATIVE * * The machine ABI rules governing the format of all ring request and * response structures. */ /* Requests from the frontend to the backend */ /* * Request a SCSI operation specified via a CDB in vscsiif_request.cmnd. * The target is specified via channel, id and lun. * * The operation to be performed is specified via a CDB in cmnd[], the length * of the CDB is in cmd_len. sc_data_direction specifies the direction of data * (to the device, from the device, or none at all). * * If data is to be transferred to or from the device the buffer(s) in the * guest memory is/are specified via one or multiple scsiif_request_segment * descriptors each specifying a memory page via a grant_ref_t, a offset into * the page and the length of the area in that page. All scsiif_request_segment * areas concatenated form the resulting data buffer used by the operation. * If the number of scsiif_request_segment areas is not too large (less than * or equal VSCSIIF_SG_TABLESIZE) the areas can be specified directly in the * seg[] array and the number of valid scsiif_request_segment elements is to be * set in nr_segments. * * If "feature-sg-grant" in the Xenstore is set it is possible to specify more * than VSCSIIF_SG_TABLESIZE scsiif_request_segment elements via indirection. * The maximum number of allowed scsiif_request_segment elements is the value * of the "feature-sg-grant" entry from Xenstore. When using indirection the * seg[] array doesn't contain specifications of the data buffers, but * references to scsiif_request_segment arrays, which in turn reference the * data buffers. While nr_segments holds the number of populated seg[] entries * (plus the set VSCSIIF_SG_GRANT bit), the number of scsiif_request_segment * elements referencing the target data buffers is calculated from the lengths * of the seg[] elements (the sum of all valid seg[].length divided by the * size of one scsiif_request_segment structure). */ #define VSCSIIF_ACT_SCSI_CDB 1 /* * Request abort of a running operation for the specified target given by * channel, id, lun and the operation's rqid in ref_rqid. */ #define VSCSIIF_ACT_SCSI_ABORT 2 /* * Request a device reset of the specified target (channel and id). */ #define VSCSIIF_ACT_SCSI_RESET 3 /* * Preset scatter/gather elements for a following request. Deprecated. * Keeping the define only to avoid usage of the value "4" for other actions. */ #define VSCSIIF_ACT_SCSI_SG_PRESET 4 /* * Maximum scatter/gather segments per request. * * Considering balance between allocating at least 16 "vscsiif_request" * structures on one page (4096 bytes) and the number of scatter/gather * elements needed, we decided to use 26 as a magic number. * * If "feature-sg-grant" is set, more scatter/gather elements can be specified * by placing them in one or more (up to VSCSIIF_SG_TABLESIZE) granted pages. * In this case the vscsiif_request seg elements don't contain references to * the user data, but to the SG elements referencing the user data. */ #define VSCSIIF_SG_TABLESIZE 26 /* * based on Linux kernel 2.6.18, still valid * Changing these values requires support of multiple protocols via the rings * as "old clients" will blindly use these values and the resulting structure * sizes. */ #define VSCSIIF_MAX_COMMAND_SIZE 16 #define VSCSIIF_SENSE_BUFFERSIZE 96 struct scsiif_request_segment { grant_ref_t gref; uint16_t offset; uint16_t length; }; #define VSCSIIF_SG_PER_PAGE (PAGE_SIZE / sizeof(struct scsiif_request_segment)) /* Size of one request is 252 bytes */ struct vscsiif_request { uint16_t rqid; /* private guest value, echoed in resp */ uint8_t act; /* command between backend and frontend */ uint8_t cmd_len; /* valid CDB bytes */ uint8_t cmnd[VSCSIIF_MAX_COMMAND_SIZE]; /* the CDB */ uint16_t timeout_per_command; /* deprecated */ uint16_t channel, id, lun; /* (virtual) device specification */ uint16_t ref_rqid; /* command abort reference */ uint8_t sc_data_direction; /* for DMA_TO_DEVICE(1) DMA_FROM_DEVICE(2) DMA_NONE(3) requests */ uint8_t nr_segments; /* Number of pieces of scatter-gather */ /* * flag in nr_segments: SG elements via grant page * * If VSCSIIF_SG_GRANT is set, the low 7 bits of nr_segments specify the number * of grant pages containing SG elements. Usable if "feature-sg-grant" set. */ #define VSCSIIF_SG_GRANT 0x80 struct scsiif_request_segment seg[VSCSIIF_SG_TABLESIZE]; uint32_t reserved[3]; }; /* Size of one response is 252 bytes */ struct vscsiif_response { uint16_t rqid; /* identifies request */ uint8_t padding; uint8_t sense_len; uint8_t sense_buffer[VSCSIIF_SENSE_BUFFERSIZE]; int32_t rslt; uint32_t residual_len; /* request bufflen - return the value from physical device */ uint32_t reserved[36]; }; DEFINE_RING_TYPES(vscsiif, struct vscsiif_request, struct vscsiif_response); #endif /*__XEN__PUBLIC_IO_SCSI_H__*/