mirror of
https://github.com/torvalds/linux.git
synced 2025-11-04 02:30:34 +02:00
e124c9a2c3
Add the definition of pvSCSI protocol used between the pvSCSI frontend in a XEN domU and the pvSCSI backend in a XEN driver domain (usually Dom0). This header was originally provided by Fujitsu for Xen based on Linux 2.6.18. Changes are: - Added comments. - Adapt to Linux style guide. - Add support for larger SG-lists by putting them in an own granted page. - Remove stale definitions. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
229 lines
8.7 KiB
C
229 lines
8.7 KiB
C
/******************************************************************************
|
|
* 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__*/
|