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Diffstat (limited to 'sys/xen/blkif.h')
| -rw-r--r-- | sys/xen/blkif.h | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/sys/xen/blkif.h b/sys/xen/blkif.h new file mode 100644 index 0000000..48b71ea --- /dev/null +++ b/sys/xen/blkif.h @@ -0,0 +1,145 @@ +/* + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to + * deal in the Software without restriction, including without limitation the + * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or + * sell copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + * + * $FreeBSD$ + */ + +#ifndef __XEN_BLKIF_H__ +#define __XEN_BLKIF_H__ + +#include <xen/interface/io/ring.h> +#include <xen/interface/io/blkif.h> +#include <xen/interface/io/protocols.h> + +/* Not a real protocol. Used to generate ring structs which contain + * the elements common to all protocols only. This way we get a + * compiler-checkable way to use common struct elements, so we can + * avoid using switch(protocol) in a number of places. */ +struct blkif_common_request { + char dummy; +}; +struct blkif_common_response { + char dummy; +}; + +/* i386 protocol version */ +#pragma pack(push, 4) +struct blkif_x86_32_request { + uint8_t operation; /* BLKIF_OP_??? */ + uint8_t nr_segments; /* number of segments */ + blkif_vdev_t handle; /* only for read/write requests */ + uint64_t id; /* private guest value, echoed in resp */ + blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ + struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK]; +}; +struct blkif_x86_32_response { + uint64_t id; /* copied from request */ + uint8_t operation; /* copied from request */ + int16_t status; /* BLKIF_RSP_??? */ +}; +typedef struct blkif_x86_32_request blkif_x86_32_request_t; +typedef struct blkif_x86_32_response blkif_x86_32_response_t; +#pragma pack(pop) + +/* x86_64 protocol version */ +struct blkif_x86_64_request { + uint8_t operation; /* BLKIF_OP_??? */ + uint8_t nr_segments; /* number of segments */ + blkif_vdev_t handle; /* only for read/write requests */ + uint64_t __attribute__((__aligned__(8))) id; + blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ + struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK]; +}; +struct blkif_x86_64_response { + uint64_t __attribute__((__aligned__(8))) id; + uint8_t operation; /* copied from request */ + int16_t status; /* BLKIF_RSP_??? */ +}; +typedef struct blkif_x86_64_request blkif_x86_64_request_t; +typedef struct blkif_x86_64_response blkif_x86_64_response_t; + +DEFINE_RING_TYPES(blkif_common, struct blkif_common_request, struct blkif_common_response); +DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request, struct blkif_x86_32_response); +DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request, struct blkif_x86_64_response); + +/* + * Maximum number of requests that can be active for a given instance + * regardless of the protocol in use, based on the ring size. This constant + * facilitates resource pre-allocation in backend drivers since the size is + * known well in advance of attaching to a front end. + */ +#define BLKIF_MAX_RING_REQUESTS(_sz) \ + MAX(__RING_SIZE((blkif_x86_64_sring_t *)NULL, _sz), \ + MAX(__RING_SIZE((blkif_x86_32_sring_t *)NULL, _sz), \ + __RING_SIZE((blkif_sring_t *)NULL, _sz))) + +/* + * The number of ring pages required to support a given number of requests + * for a given instance regardless of the protocol in use. + */ +#define BLKIF_RING_PAGES(_entries) \ + MAX(__RING_PAGES((blkif_x86_64_sring_t *)NULL, _entries), \ + MAX(__RING_PAGES((blkif_x86_32_sring_t *)NULL, _entries), \ + __RING_PAGES((blkif_sring_t *)NULL, _entries))) + +union blkif_back_rings { + blkif_back_ring_t native; + blkif_common_back_ring_t common; + blkif_x86_32_back_ring_t x86_32; + blkif_x86_64_back_ring_t x86_64; +}; +typedef union blkif_back_rings blkif_back_rings_t; + +enum blkif_protocol { + BLKIF_PROTOCOL_NATIVE = 1, + BLKIF_PROTOCOL_X86_32 = 2, + BLKIF_PROTOCOL_X86_64 = 3, +}; + +static void inline blkif_get_x86_32_req(blkif_request_t *dst, blkif_x86_32_request_t *src) +{ + int i, n = BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK; + dst->operation = src->operation; + dst->nr_segments = src->nr_segments; + dst->handle = src->handle; + dst->id = src->id; + dst->sector_number = src->sector_number; + barrier(); + if (n > dst->nr_segments) + n = dst->nr_segments; + for (i = 0; i < n; i++) + dst->seg[i] = src->seg[i]; +} + +static void inline blkif_get_x86_64_req(blkif_request_t *dst, blkif_x86_64_request_t *src) +{ + int i, n = BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK; + dst->operation = src->operation; + dst->nr_segments = src->nr_segments; + dst->handle = src->handle; + dst->id = src->id; + dst->sector_number = src->sector_number; + barrier(); + if (n > dst->nr_segments) + n = dst->nr_segments; + for (i = 0; i < n; i++) + dst->seg[i] = src->seg[i]; +} + +#endif /* __XEN_BLKIF_H__ */ |
