| /* SPDX-License-Identifier: MIT */ |
| /****************************************************************************** |
| * vscsiif.h |
| * |
| * Based on the blkif.h code. |
| * |
| * 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__*/ |
