FreeBSD/Linux Kernel Cross Reference
sys/xen/blkif.h
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: releng/11.2/sys/xen/blkif.h 289686 2015-10-21 10:44:07Z royger $
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. */
34 struct blkif_common_request {
35 char dummy;
36 };
37 struct blkif_common_response {
38 char dummy;
39 };
40
41 /* i386 protocol version */
42 #pragma pack(push, 4)
43 struct 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 };
51 struct 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 };
56 typedef struct blkif_x86_32_request blkif_x86_32_request_t;
57 typedef struct blkif_x86_32_response blkif_x86_32_response_t;
58 #pragma pack(pop)
59
60 /* x86_64 protocol version */
61 struct 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 };
69 struct 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 };
74 typedef struct blkif_x86_64_request blkif_x86_64_request_t;
75 typedef struct blkif_x86_64_response blkif_x86_64_response_t;
76
77 DEFINE_RING_TYPES(blkif_common, struct blkif_common_request, struct blkif_common_response);
78 DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request, struct blkif_x86_32_response);
79 DEFINE_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
101 union 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 };
107 typedef union blkif_back_rings blkif_back_rings_t;
108
109 enum blkif_protocol {
110 BLKIF_PROTOCOL_NATIVE = 1,
111 BLKIF_PROTOCOL_X86_32 = 2,
112 BLKIF_PROTOCOL_X86_64 = 3,
113 };
114
115 static 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
130 static 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__ */
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