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9e2b3e834c
Commit b24413180f ("License cleanup: add SPDX GPL-2.0 license
identifier to files with no license") was meant to do a tree-wide
cleanup for files without any license information by adding a SPDX
GPL-2.0 line to them.
Unfortunately this was applied even to several Xen-related headers
which have been originally under the MIT license, but obviously have
been copied to the Linux tree from the Xen project without keeping the
license boiler plate as required.
Correct that by changing the license of those files back to "MIT".
Some files still contain the MIT license text. Replace that by the
related SPDX line.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20211015143312.29900-1-jgross@suse.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
302 lines
13 KiB
C
302 lines
13 KiB
C
/* SPDX-License-Identifier: MIT */
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/******************************************************************************
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* blkif.h
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*
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* Unified block-device I/O interface for Xen guest OSes.
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*
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* Copyright (c) 2003-2004, Keir Fraser
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*/
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#ifndef __XEN_PUBLIC_IO_BLKIF_H__
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#define __XEN_PUBLIC_IO_BLKIF_H__
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#include <xen/interface/io/ring.h>
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#include <xen/interface/grant_table.h>
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/*
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* Front->back notifications: When enqueuing a new request, sending a
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* notification can be made conditional on req_event (i.e., the generic
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* hold-off mechanism provided by the ring macros). Backends must set
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* req_event appropriately (e.g., using RING_FINAL_CHECK_FOR_REQUESTS()).
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*
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* Back->front notifications: When enqueuing a new response, sending a
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* notification can be made conditional on rsp_event (i.e., the generic
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* hold-off mechanism provided by the ring macros). Frontends must set
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* rsp_event appropriately (e.g., using RING_FINAL_CHECK_FOR_RESPONSES()).
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*/
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typedef uint16_t blkif_vdev_t;
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typedef uint64_t blkif_sector_t;
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/*
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* Multiple hardware queues/rings:
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* If supported, the backend will write the key "multi-queue-max-queues" to
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* the directory for that vbd, and set its value to the maximum supported
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* number of queues.
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* Frontends that are aware of this feature and wish to use it can write the
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* key "multi-queue-num-queues" with the number they wish to use, which must be
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* greater than zero, and no more than the value reported by the backend in
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* "multi-queue-max-queues".
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*
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* For frontends requesting just one queue, the usual event-channel and
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* ring-ref keys are written as before, simplifying the backend processing
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* to avoid distinguishing between a frontend that doesn't understand the
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* multi-queue feature, and one that does, but requested only one queue.
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*
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* Frontends requesting two or more queues must not write the toplevel
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* event-channel and ring-ref keys, instead writing those keys under sub-keys
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* having the name "queue-N" where N is the integer ID of the queue/ring for
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* which those keys belong. Queues are indexed from zero.
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* For example, a frontend with two queues must write the following set of
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* queue-related keys:
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*
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* /local/domain/1/device/vbd/0/multi-queue-num-queues = "2"
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* /local/domain/1/device/vbd/0/queue-0 = ""
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* /local/domain/1/device/vbd/0/queue-0/ring-ref = "<ring-ref#0>"
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* /local/domain/1/device/vbd/0/queue-0/event-channel = "<evtchn#0>"
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* /local/domain/1/device/vbd/0/queue-1 = ""
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* /local/domain/1/device/vbd/0/queue-1/ring-ref = "<ring-ref#1>"
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* /local/domain/1/device/vbd/0/queue-1/event-channel = "<evtchn#1>"
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*
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* It is also possible to use multiple queues/rings together with
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* feature multi-page ring buffer.
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* For example, a frontend requests two queues/rings and the size of each ring
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* buffer is two pages must write the following set of related keys:
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*
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* /local/domain/1/device/vbd/0/multi-queue-num-queues = "2"
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* /local/domain/1/device/vbd/0/ring-page-order = "1"
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* /local/domain/1/device/vbd/0/queue-0 = ""
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* /local/domain/1/device/vbd/0/queue-0/ring-ref0 = "<ring-ref#0>"
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* /local/domain/1/device/vbd/0/queue-0/ring-ref1 = "<ring-ref#1>"
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* /local/domain/1/device/vbd/0/queue-0/event-channel = "<evtchn#0>"
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* /local/domain/1/device/vbd/0/queue-1 = ""
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* /local/domain/1/device/vbd/0/queue-1/ring-ref0 = "<ring-ref#2>"
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* /local/domain/1/device/vbd/0/queue-1/ring-ref1 = "<ring-ref#3>"
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* /local/domain/1/device/vbd/0/queue-1/event-channel = "<evtchn#1>"
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*
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*/
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/*
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* REQUEST CODES.
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*/
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#define BLKIF_OP_READ 0
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#define BLKIF_OP_WRITE 1
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/*
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* Recognised only if "feature-barrier" is present in backend xenbus info.
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* The "feature_barrier" node contains a boolean indicating whether barrier
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* requests are likely to succeed or fail. Either way, a barrier request
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* may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by
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* the underlying block-device hardware. The boolean simply indicates whether
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* or not it is worthwhile for the frontend to attempt barrier requests.
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* If a backend does not recognise BLKIF_OP_WRITE_BARRIER, it should *not*
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* create the "feature-barrier" node!
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*/
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#define BLKIF_OP_WRITE_BARRIER 2
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/*
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* Recognised if "feature-flush-cache" is present in backend xenbus
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* info. A flush will ask the underlying storage hardware to flush its
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* non-volatile caches as appropriate. The "feature-flush-cache" node
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* contains a boolean indicating whether flush requests are likely to
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* succeed or fail. Either way, a flush request may fail at any time
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* with BLKIF_RSP_EOPNOTSUPP if it is unsupported by the underlying
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* block-device hardware. The boolean simply indicates whether or not it
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* is worthwhile for the frontend to attempt flushes. If a backend does
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* not recognise BLKIF_OP_WRITE_FLUSH_CACHE, it should *not* create the
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* "feature-flush-cache" node!
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*/
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#define BLKIF_OP_FLUSH_DISKCACHE 3
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/*
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* Recognised only if "feature-discard" is present in backend xenbus info.
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* The "feature-discard" node contains a boolean indicating whether trim
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* (ATA) or unmap (SCSI) - conviently called discard requests are likely
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* to succeed or fail. Either way, a discard request
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* may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by
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* the underlying block-device hardware. The boolean simply indicates whether
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* or not it is worthwhile for the frontend to attempt discard requests.
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* If a backend does not recognise BLKIF_OP_DISCARD, it should *not*
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* create the "feature-discard" node!
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*
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* Discard operation is a request for the underlying block device to mark
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* extents to be erased. However, discard does not guarantee that the blocks
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* will be erased from the device - it is just a hint to the device
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* controller that these blocks are no longer in use. What the device
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* controller does with that information is left to the controller.
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* Discard operations are passed with sector_number as the
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* sector index to begin discard operations at and nr_sectors as the number of
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* sectors to be discarded. The specified sectors should be discarded if the
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* underlying block device supports trim (ATA) or unmap (SCSI) operations,
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* or a BLKIF_RSP_EOPNOTSUPP should be returned.
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* More information about trim/unmap operations at:
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* http://t13.org/Documents/UploadedDocuments/docs2008/
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* e07154r6-Data_Set_Management_Proposal_for_ATA-ACS2.doc
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* http://www.seagate.com/staticfiles/support/disc/manuals/
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* Interface%20manuals/100293068c.pdf
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* The backend can optionally provide three extra XenBus attributes to
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* further optimize the discard functionality:
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* 'discard-alignment' - Devices that support discard functionality may
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* internally allocate space in units that are bigger than the exported
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* logical block size. The discard-alignment parameter indicates how many bytes
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* the beginning of the partition is offset from the internal allocation unit's
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* natural alignment.
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* 'discard-granularity' - Devices that support discard functionality may
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* internally allocate space using units that are bigger than the logical block
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* size. The discard-granularity parameter indicates the size of the internal
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* allocation unit in bytes if reported by the device. Otherwise the
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* discard-granularity will be set to match the device's physical block size.
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* 'discard-secure' - All copies of the discarded sectors (potentially created
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* by garbage collection) must also be erased. To use this feature, the flag
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* BLKIF_DISCARD_SECURE must be set in the blkif_request_trim.
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*/
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#define BLKIF_OP_DISCARD 5
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/*
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* Recognized if "feature-max-indirect-segments" in present in the backend
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* xenbus info. The "feature-max-indirect-segments" node contains the maximum
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* number of segments allowed by the backend per request. If the node is
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* present, the frontend might use blkif_request_indirect structs in order to
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* issue requests with more than BLKIF_MAX_SEGMENTS_PER_REQUEST (11). The
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* maximum number of indirect segments is fixed by the backend, but the
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* frontend can issue requests with any number of indirect segments as long as
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* it's less than the number provided by the backend. The indirect_grefs field
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* in blkif_request_indirect should be filled by the frontend with the
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* grant references of the pages that are holding the indirect segments.
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* These pages are filled with an array of blkif_request_segment that hold the
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* information about the segments. The number of indirect pages to use is
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* determined by the number of segments an indirect request contains. Every
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* indirect page can contain a maximum of
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* (PAGE_SIZE / sizeof(struct blkif_request_segment)) segments, so to
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* calculate the number of indirect pages to use we have to do
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* ceil(indirect_segments / (PAGE_SIZE / sizeof(struct blkif_request_segment))).
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*
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* If a backend does not recognize BLKIF_OP_INDIRECT, it should *not*
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* create the "feature-max-indirect-segments" node!
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*/
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#define BLKIF_OP_INDIRECT 6
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/*
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* Maximum scatter/gather segments per request.
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* This is carefully chosen so that sizeof(struct blkif_ring) <= PAGE_SIZE.
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* NB. This could be 12 if the ring indexes weren't stored in the same page.
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*/
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#define BLKIF_MAX_SEGMENTS_PER_REQUEST 11
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#define BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST 8
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struct blkif_request_segment {
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grant_ref_t gref; /* reference to I/O buffer frame */
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/* @first_sect: first sector in frame to transfer (inclusive). */
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/* @last_sect: last sector in frame to transfer (inclusive). */
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uint8_t first_sect, last_sect;
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};
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struct blkif_request_rw {
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uint8_t nr_segments; /* number of segments */
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blkif_vdev_t handle; /* only for read/write requests */
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#ifndef CONFIG_X86_32
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uint32_t _pad1; /* offsetof(blkif_request,u.rw.id) == 8 */
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#endif
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uint64_t id; /* private guest value, echoed in resp */
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blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
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struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
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} __attribute__((__packed__));
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struct blkif_request_discard {
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uint8_t flag; /* BLKIF_DISCARD_SECURE or zero. */
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#define BLKIF_DISCARD_SECURE (1<<0) /* ignored if discard-secure=0 */
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blkif_vdev_t _pad1; /* only for read/write requests */
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#ifndef CONFIG_X86_32
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uint32_t _pad2; /* offsetof(blkif_req..,u.discard.id)==8*/
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#endif
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uint64_t id; /* private guest value, echoed in resp */
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blkif_sector_t sector_number;
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uint64_t nr_sectors;
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uint8_t _pad3;
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} __attribute__((__packed__));
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struct blkif_request_other {
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uint8_t _pad1;
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blkif_vdev_t _pad2; /* only for read/write requests */
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#ifndef CONFIG_X86_32
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uint32_t _pad3; /* offsetof(blkif_req..,u.other.id)==8*/
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#endif
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uint64_t id; /* private guest value, echoed in resp */
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} __attribute__((__packed__));
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struct blkif_request_indirect {
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uint8_t indirect_op;
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uint16_t nr_segments;
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#ifndef CONFIG_X86_32
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uint32_t _pad1; /* offsetof(blkif_...,u.indirect.id) == 8 */
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#endif
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uint64_t id;
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blkif_sector_t sector_number;
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blkif_vdev_t handle;
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uint16_t _pad2;
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grant_ref_t indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST];
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#ifndef CONFIG_X86_32
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uint32_t _pad3; /* make it 64 byte aligned */
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#else
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uint64_t _pad3; /* make it 64 byte aligned */
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#endif
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} __attribute__((__packed__));
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struct blkif_request {
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uint8_t operation; /* BLKIF_OP_??? */
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union {
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struct blkif_request_rw rw;
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struct blkif_request_discard discard;
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struct blkif_request_other other;
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struct blkif_request_indirect indirect;
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} u;
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} __attribute__((__packed__));
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struct blkif_response {
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uint64_t id; /* copied from request */
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uint8_t operation; /* copied from request */
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int16_t status; /* BLKIF_RSP_??? */
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};
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/*
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* STATUS RETURN CODES.
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*/
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/* Operation not supported (only happens on barrier writes). */
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#define BLKIF_RSP_EOPNOTSUPP -2
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/* Operation failed for some unspecified reason (-EIO). */
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#define BLKIF_RSP_ERROR -1
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/* Operation completed successfully. */
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#define BLKIF_RSP_OKAY 0
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/*
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* Generate blkif ring structures and types.
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*/
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DEFINE_RING_TYPES(blkif, struct blkif_request, struct blkif_response);
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#define VDISK_CDROM 0x1
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#define VDISK_REMOVABLE 0x2
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#define VDISK_READONLY 0x4
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/* Xen-defined major numbers for virtual disks, they look strangely
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* familiar */
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#define XEN_IDE0_MAJOR 3
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#define XEN_IDE1_MAJOR 22
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#define XEN_SCSI_DISK0_MAJOR 8
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#define XEN_SCSI_DISK1_MAJOR 65
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#define XEN_SCSI_DISK2_MAJOR 66
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#define XEN_SCSI_DISK3_MAJOR 67
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#define XEN_SCSI_DISK4_MAJOR 68
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#define XEN_SCSI_DISK5_MAJOR 69
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#define XEN_SCSI_DISK6_MAJOR 70
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#define XEN_SCSI_DISK7_MAJOR 71
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#define XEN_SCSI_DISK8_MAJOR 128
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#define XEN_SCSI_DISK9_MAJOR 129
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#define XEN_SCSI_DISK10_MAJOR 130
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#define XEN_SCSI_DISK11_MAJOR 131
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#define XEN_SCSI_DISK12_MAJOR 132
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#define XEN_SCSI_DISK13_MAJOR 133
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#define XEN_SCSI_DISK14_MAJOR 134
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#define XEN_SCSI_DISK15_MAJOR 135
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#endif /* __XEN_PUBLIC_IO_BLKIF_H__ */
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