mirror of
https://github.com/freebsd/freebsd-src
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144 lines
5.5 KiB
C
144 lines
5.5 KiB
C
/*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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#ifndef __XEN_BLKIF_H__
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#define __XEN_BLKIF_H__
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#include <contrib/xen/io/ring.h>
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#include <contrib/xen/io/blkif.h>
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#include <contrib/xen/io/protocols.h>
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/* Not a real protocol. Used to generate ring structs which contain
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* the elements common to all protocols only. This way we get a
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* compiler-checkable way to use common struct elements, so we can
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* avoid using switch(protocol) in a number of places. */
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struct blkif_common_request {
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char dummy;
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};
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struct blkif_common_response {
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char dummy;
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};
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/* i386 protocol version */
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#pragma pack(push, 4)
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struct blkif_x86_32_request {
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uint8_t operation; /* BLKIF_OP_??? */
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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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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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};
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struct blkif_x86_32_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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typedef struct blkif_x86_32_request blkif_x86_32_request_t;
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typedef struct blkif_x86_32_response blkif_x86_32_response_t;
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#pragma pack(pop)
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/* x86_64 protocol version */
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struct blkif_x86_64_request {
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uint8_t operation; /* BLKIF_OP_??? */
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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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uint64_t __attribute__((__aligned__(8))) id;
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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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};
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struct blkif_x86_64_response {
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uint64_t __attribute__((__aligned__(8))) id;
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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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typedef struct blkif_x86_64_request blkif_x86_64_request_t;
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typedef struct blkif_x86_64_response blkif_x86_64_response_t;
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DEFINE_RING_TYPES(blkif_common, struct blkif_common_request, struct blkif_common_response);
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DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request, struct blkif_x86_32_response);
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DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request, struct blkif_x86_64_response);
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/*
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* Maximum number of requests that can be active for a given instance
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* regardless of the protocol in use, based on the ring size. This constant
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* facilitates resource pre-allocation in backend drivers since the size is
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* known well in advance of attaching to a front end.
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*/
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#define BLKIF_MAX_RING_REQUESTS(_sz) \
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MAX(__RING_SIZE((blkif_x86_64_sring_t *)NULL, _sz), \
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MAX(__RING_SIZE((blkif_x86_32_sring_t *)NULL, _sz), \
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__RING_SIZE((blkif_sring_t *)NULL, _sz)))
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/*
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* The number of ring pages required to support a given number of requests
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* for a given instance regardless of the protocol in use.
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*/
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#define BLKIF_RING_PAGES(_entries) \
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MAX(__RING_PAGES((blkif_x86_64_sring_t *)NULL, _entries), \
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MAX(__RING_PAGES((blkif_x86_32_sring_t *)NULL, _entries), \
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__RING_PAGES((blkif_sring_t *)NULL, _entries)))
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union blkif_back_rings {
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blkif_back_ring_t native;
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blkif_common_back_ring_t common;
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blkif_x86_32_back_ring_t x86_32;
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blkif_x86_64_back_ring_t x86_64;
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};
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typedef union blkif_back_rings blkif_back_rings_t;
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enum blkif_protocol {
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BLKIF_PROTOCOL_NATIVE = 1,
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BLKIF_PROTOCOL_X86_32 = 2,
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BLKIF_PROTOCOL_X86_64 = 3,
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};
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static void inline blkif_get_x86_32_req(blkif_request_t *dst, blkif_x86_32_request_t *src)
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{
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int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
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dst->operation = src->operation;
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dst->nr_segments = src->nr_segments;
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dst->handle = src->handle;
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dst->id = src->id;
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dst->sector_number = src->sector_number;
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__compiler_membar();
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if (n > dst->nr_segments)
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n = dst->nr_segments;
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for (i = 0; i < n; i++)
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dst->seg[i] = src->seg[i];
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}
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static void inline blkif_get_x86_64_req(blkif_request_t *dst, blkif_x86_64_request_t *src)
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{
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int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
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dst->operation = src->operation;
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dst->nr_segments = src->nr_segments;
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dst->handle = src->handle;
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dst->id = src->id;
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dst->sector_number = src->sector_number;
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__compiler_membar();
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if (n > dst->nr_segments)
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n = dst->nr_segments;
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for (i = 0; i < n; i++)
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dst->seg[i] = src->seg[i];
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}
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#endif /* __XEN_BLKIF_H__ */
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