blkif.h revision 97e36834f5a106459ab1b290e663a4eb6264639e
1a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge/****************************************************************************** 2a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * blkif.h 3a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * 4a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * Unified block-device I/O interface for Xen guest OSes. 5a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * 6a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * Copyright (c) 2003-2004, Keir Fraser 7a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge */ 8a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge 9a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge#ifndef __XEN_PUBLIC_IO_BLKIF_H__ 10a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge#define __XEN_PUBLIC_IO_BLKIF_H__ 11a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge 12a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge#include "ring.h" 13a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge#include "../grant_table.h" 14a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge 15a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge/* 16a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * Front->back notifications: When enqueuing a new request, sending a 17a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * notification can be made conditional on req_event (i.e., the generic 18a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * hold-off mechanism provided by the ring macros). Backends must set 19a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * req_event appropriately (e.g., using RING_FINAL_CHECK_FOR_REQUESTS()). 20a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * 21a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * Back->front notifications: When enqueuing a new response, sending a 22a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * notification can be made conditional on rsp_event (i.e., the generic 23a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * hold-off mechanism provided by the ring macros). Frontends must set 24a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * rsp_event appropriately (e.g., using RING_FINAL_CHECK_FOR_RESPONSES()). 25a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge */ 26a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge 27a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardingetypedef uint16_t blkif_vdev_t; 28a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardingetypedef uint64_t blkif_sector_t; 29a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge 30a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge/* 31a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * REQUEST CODES. 32a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge */ 33a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge#define BLKIF_OP_READ 0 34a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge#define BLKIF_OP_WRITE 1 35a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge/* 36a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * Recognised only if "feature-barrier" is present in backend xenbus info. 37a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * The "feature_barrier" node contains a boolean indicating whether barrier 38a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * requests are likely to succeed or fail. Either way, a barrier request 39a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by 40a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * the underlying block-device hardware. The boolean simply indicates whether 41a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * or not it is worthwhile for the frontend to attempt barrier requests. 42a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * If a backend does not recognise BLKIF_OP_WRITE_BARRIER, it should *not* 43a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * create the "feature-barrier" node! 44a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge */ 45a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge#define BLKIF_OP_WRITE_BARRIER 2 46a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge 47a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge/* 486dcfb751c927879399e404b3885cbdef7d8d368bKonrad Rzeszutek Wilk * Recognised if "feature-flush-cache" is present in backend xenbus 496dcfb751c927879399e404b3885cbdef7d8d368bKonrad Rzeszutek Wilk * info. A flush will ask the underlying storage hardware to flush its 506dcfb751c927879399e404b3885cbdef7d8d368bKonrad Rzeszutek Wilk * non-volatile caches as appropriate. The "feature-flush-cache" node 516dcfb751c927879399e404b3885cbdef7d8d368bKonrad Rzeszutek Wilk * contains a boolean indicating whether flush requests are likely to 526dcfb751c927879399e404b3885cbdef7d8d368bKonrad Rzeszutek Wilk * succeed or fail. Either way, a flush request may fail at any time 536dcfb751c927879399e404b3885cbdef7d8d368bKonrad Rzeszutek Wilk * with BLKIF_RSP_EOPNOTSUPP if it is unsupported by the underlying 546dcfb751c927879399e404b3885cbdef7d8d368bKonrad Rzeszutek Wilk * block-device hardware. The boolean simply indicates whether or not it 556dcfb751c927879399e404b3885cbdef7d8d368bKonrad Rzeszutek Wilk * is worthwhile for the frontend to attempt flushes. If a backend does 566dcfb751c927879399e404b3885cbdef7d8d368bKonrad Rzeszutek Wilk * not recognise BLKIF_OP_WRITE_FLUSH_CACHE, it should *not* create the 576dcfb751c927879399e404b3885cbdef7d8d368bKonrad Rzeszutek Wilk * "feature-flush-cache" node! 586dcfb751c927879399e404b3885cbdef7d8d368bKonrad Rzeszutek Wilk */ 596dcfb751c927879399e404b3885cbdef7d8d368bKonrad Rzeszutek Wilk#define BLKIF_OP_FLUSH_DISKCACHE 3 6032a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang 6132a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang/* 6232a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * Recognised only if "feature-discard" is present in backend xenbus info. 6332a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * The "feature-discard" node contains a boolean indicating whether trim 6432a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * (ATA) or unmap (SCSI) - conviently called discard requests are likely 6532a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * to succeed or fail. Either way, a discard request 6632a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by 6732a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * the underlying block-device hardware. The boolean simply indicates whether 6832a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * or not it is worthwhile for the frontend to attempt discard requests. 6932a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * If a backend does not recognise BLKIF_OP_DISCARD, it should *not* 7032a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * create the "feature-discard" node! 7132a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * 7232a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * Discard operation is a request for the underlying block device to mark 7332a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * extents to be erased. However, discard does not guarantee that the blocks 7432a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * will be erased from the device - it is just a hint to the device 7532a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * controller that these blocks are no longer in use. What the device 7632a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * controller does with that information is left to the controller. 7732a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * Discard operations are passed with sector_number as the 7832a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * sector index to begin discard operations at and nr_sectors as the number of 7932a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * sectors to be discarded. The specified sectors should be discarded if the 8032a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * underlying block device supports trim (ATA) or unmap (SCSI) operations, 8132a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * or a BLKIF_RSP_EOPNOTSUPP should be returned. 8232a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * More information about trim/unmap operations at: 8332a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * http://t13.org/Documents/UploadedDocuments/docs2008/ 8432a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * e07154r6-Data_Set_Management_Proposal_for_ATA-ACS2.doc 8532a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * http://www.seagate.com/staticfiles/support/disc/manuals/ 8632a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang * Interface%20manuals/100293068c.pdf 8732a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang */ 8832a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang#define BLKIF_OP_DISCARD 5 8932a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang 906dcfb751c927879399e404b3885cbdef7d8d368bKonrad Rzeszutek Wilk/* 91a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * Maximum scatter/gather segments per request. 92a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * This is carefully chosen so that sizeof(struct blkif_ring) <= PAGE_SIZE. 93a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * NB. This could be 12 if the ring indexes weren't stored in the same page. 94a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge */ 95a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge#define BLKIF_MAX_SEGMENTS_PER_REQUEST 11 96a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge 9751de69523ffe1c17994dc2f260369f29dfdce71cOwen Smithstruct blkif_request_rw { 9897e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk uint8_t nr_segments; /* number of segments */ 9997e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk blkif_vdev_t handle; /* only for read/write requests */ 10097e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk#ifdef CONFIG_X86_64 10197e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk uint32_t _pad1; /* offsetof(blkif_request,u.rw.id) == 8 */ 10297e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk#endif 10397e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk uint64_t id; /* private guest value, echoed in resp */ 104a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ 105a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge struct blkif_request_segment { 106a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge grant_ref_t gref; /* reference to I/O buffer frame */ 107a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge /* @first_sect: first sector in frame to transfer (inclusive). */ 108a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge /* @last_sect: last sector in frame to transfer (inclusive). */ 109a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge uint8_t first_sect, last_sect; 110a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge } seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; 11197e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk} __attribute__((__packed__)); 112a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge 11332a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyangstruct blkif_request_discard { 11497e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk uint8_t nr_segments; /* number of segments */ 11597e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk blkif_vdev_t _pad1; /* only for read/write requests */ 11697e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk#ifdef CONFIG_X86_64 11797e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk uint32_t _pad2; /* offsetof(blkif_req..,u.discard.id)==8*/ 11897e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk#endif 11997e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk uint64_t id; /* private guest value, echoed in resp */ 12032a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang blkif_sector_t sector_number; 12197e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk uint64_t nr_sectors; 12297e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk uint8_t _pad3; 12397e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk} __attribute__((__packed__)); 12432a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang 12551de69523ffe1c17994dc2f260369f29dfdce71cOwen Smithstruct blkif_request { 12651de69523ffe1c17994dc2f260369f29dfdce71cOwen Smith uint8_t operation; /* BLKIF_OP_??? */ 12751de69523ffe1c17994dc2f260369f29dfdce71cOwen Smith union { 12851de69523ffe1c17994dc2f260369f29dfdce71cOwen Smith struct blkif_request_rw rw; 12932a8d26cc9b96629269e04ee6c583e14398f6f47Li Dongyang struct blkif_request_discard discard; 13051de69523ffe1c17994dc2f260369f29dfdce71cOwen Smith } u; 13197e36834f5a106459ab1b290e663a4eb6264639eKonrad Rzeszutek Wilk} __attribute__((__packed__)); 13251de69523ffe1c17994dc2f260369f29dfdce71cOwen Smith 133a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardingestruct blkif_response { 134a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge uint64_t id; /* copied from request */ 135a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge uint8_t operation; /* copied from request */ 136a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge int16_t status; /* BLKIF_RSP_??? */ 137a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge}; 138a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge 139a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge/* 140a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * STATUS RETURN CODES. 141a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge */ 142a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge /* Operation not supported (only happens on barrier writes). */ 143a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge#define BLKIF_RSP_EOPNOTSUPP -2 144a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge /* Operation failed for some unspecified reason (-EIO). */ 145a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge#define BLKIF_RSP_ERROR -1 146a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge /* Operation completed successfully. */ 147a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge#define BLKIF_RSP_OKAY 0 148a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge 149a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge/* 150a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge * Generate blkif ring structures and types. 151a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge */ 152a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge 153a42089dd358a7673a0a23126589a9029e57c2049Jeremy FitzhardingeDEFINE_RING_TYPES(blkif, struct blkif_request, struct blkif_response); 154a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge 155a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge#define VDISK_CDROM 0x1 156a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge#define VDISK_REMOVABLE 0x2 157a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge#define VDISK_READONLY 0x4 158a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge 159c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini/* Xen-defined major numbers for virtual disks, they look strangely 160c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini * familiar */ 161c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_IDE0_MAJOR 3 162c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_IDE1_MAJOR 22 163c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK0_MAJOR 8 164c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK1_MAJOR 65 165c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK2_MAJOR 66 166c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK3_MAJOR 67 167c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK4_MAJOR 68 168c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK5_MAJOR 69 169c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK6_MAJOR 70 170c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK7_MAJOR 71 171c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK8_MAJOR 128 172c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK9_MAJOR 129 173c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK10_MAJOR 130 174c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK11_MAJOR 131 175c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK12_MAJOR 132 176c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK13_MAJOR 133 177c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK14_MAJOR 134 178c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini#define XEN_SCSI_DISK15_MAJOR 135 179c80a420995e721099906607b07c09a24543b31d9Stefano Stabellini 180a42089dd358a7673a0a23126589a9029e57c2049Jeremy Fitzhardinge#endif /* __XEN_PUBLIC_IO_BLKIF_H__ */ 181