1/*
2 * Permission is hereby granted, free of charge, to any person obtaining a copy
3 * of this software and associated documentation files (the "Software"), to
4 * deal in the Software without restriction, including without limitation the
5 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
6 * sell copies of the Software, and to permit persons to whom the Software is
7 * furnished to do so, subject to the following conditions:
8 *
9 * The above copyright notice and this permission notice shall be included in
10 * all copies or substantial portions of the Software.
11 *
12 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
13 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
14 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
15 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
16 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
17 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
18 * DEALINGS IN THE SOFTWARE.
19 *
20 * $FreeBSD$
21 */
22
23#ifndef __XEN_BLKIF_H__
24#define __XEN_BLKIF_H__
25
26#include <xen/interface/io/ring.h>
27#include <xen/interface/io/blkif.h>
28#include <xen/interface/io/protocols.h>
29
30/* Not a real protocol.  Used to generate ring structs which contain
31 * the elements common to all protocols only.  This way we get a
32 * compiler-checkable way to use common struct elements, so we can
33 * avoid using switch(protocol) in a number of places.  */
34struct blkif_common_request {
35	char dummy;
36};
37struct blkif_common_response {
38	char dummy;
39};
40
41/* i386 protocol version */
42#pragma pack(push, 4)
43struct blkif_x86_32_request {
44	uint8_t        operation;    /* BLKIF_OP_???                         */
45	uint8_t        nr_segments;  /* number of segments                   */
46	blkif_vdev_t   handle;       /* only for read/write requests         */
47	uint64_t       id;           /* private guest value, echoed in resp  */
48	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
49	struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
50};
51struct blkif_x86_32_response {
52	uint64_t        id;              /* copied from request */
53	uint8_t         operation;       /* copied from request */
54	int16_t         status;          /* BLKIF_RSP_???       */
55};
56typedef struct blkif_x86_32_request blkif_x86_32_request_t;
57typedef struct blkif_x86_32_response blkif_x86_32_response_t;
58#pragma pack(pop)
59
60/* x86_64 protocol version */
61struct blkif_x86_64_request {
62	uint8_t        operation;    /* BLKIF_OP_???                         */
63	uint8_t        nr_segments;  /* number of segments                   */
64	blkif_vdev_t   handle;       /* only for read/write requests         */
65	uint64_t       __attribute__((__aligned__(8))) id;
66	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
67	struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
68};
69struct blkif_x86_64_response {
70	uint64_t       __attribute__((__aligned__(8))) id;
71	uint8_t         operation;       /* copied from request */
72	int16_t         status;          /* BLKIF_RSP_???       */
73};
74typedef struct blkif_x86_64_request blkif_x86_64_request_t;
75typedef struct blkif_x86_64_response blkif_x86_64_response_t;
76
77DEFINE_RING_TYPES(blkif_common, struct blkif_common_request, struct blkif_common_response);
78DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request, struct blkif_x86_32_response);
79DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request, struct blkif_x86_64_response);
80
81/*
82 * Maximum number of requests that can be active for a given instance
83 * regardless of the protocol in use, based on the ring size.  This constant
84 * facilitates resource pre-allocation in backend drivers since the size is
85 * known well in advance of attaching to a front end.
86 */
87#define BLKIF_MAX_RING_REQUESTS(_sz) \
88	MAX(__RING_SIZE((blkif_x86_64_sring_t *)NULL, _sz),	\
89	    MAX(__RING_SIZE((blkif_x86_32_sring_t *)NULL, _sz),	\
90		__RING_SIZE((blkif_sring_t *)NULL, _sz)))
91
92/*
93 * The number of ring pages required to support a given number of requests
94 * for a given instance regardless of the protocol in use.
95 */
96#define BLKIF_RING_PAGES(_entries) \
97	MAX(__RING_PAGES((blkif_x86_64_sring_t *)NULL, _entries),	\
98	    MAX(__RING_PAGES((blkif_x86_32_sring_t *)NULL, _entries),	\
99		__RING_PAGES((blkif_sring_t *)NULL, _entries)))
100
101union blkif_back_rings {
102	blkif_back_ring_t        native;
103	blkif_common_back_ring_t common;
104	blkif_x86_32_back_ring_t x86_32;
105	blkif_x86_64_back_ring_t x86_64;
106};
107typedef union blkif_back_rings blkif_back_rings_t;
108
109enum blkif_protocol {
110	BLKIF_PROTOCOL_NATIVE = 1,
111	BLKIF_PROTOCOL_X86_32 = 2,
112	BLKIF_PROTOCOL_X86_64 = 3,
113};
114
115static void inline blkif_get_x86_32_req(blkif_request_t *dst, blkif_x86_32_request_t *src)
116{
117	int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
118	dst->operation = src->operation;
119	dst->nr_segments = src->nr_segments;
120	dst->handle = src->handle;
121	dst->id = src->id;
122	dst->sector_number = src->sector_number;
123	__compiler_membar();
124	if (n > dst->nr_segments)
125		n = dst->nr_segments;
126	for (i = 0; i < n; i++)
127		dst->seg[i] = src->seg[i];
128}
129
130static void inline blkif_get_x86_64_req(blkif_request_t *dst, blkif_x86_64_request_t *src)
131{
132	int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
133	dst->operation = src->operation;
134	dst->nr_segments = src->nr_segments;
135	dst->handle = src->handle;
136	dst->id = src->id;
137	dst->sector_number = src->sector_number;
138	__compiler_membar();
139	if (n > dst->nr_segments)
140		n = dst->nr_segments;
141	for (i = 0; i < n; i++)
142		dst->seg[i] = src->seg[i];
143}
144
145#endif /* __XEN_BLKIF_H__ */
146