LXR qemu/hw/block/xen

   1#ifndef __XEN_BLKIF_H__
   2#define __XEN_BLKIF_H__
   3
   4#include <xen/io/ring.h>
   5#include <xen/io/blkif.h>
   6#include <xen/io/protocols.h>
   7
   8/* Not a real protocol.  Used to generate ring structs which contain
   9 * the elements common to all protocols only.  This way we get a
  10 * compiler-checkable way to use common struct elements, so we can
  11 * avoid using switch(protocol) in a number of places.  */
  12struct blkif_common_request {
  13        char dummy;
  14};
  15struct blkif_common_response {
  16        char dummy;
  17};
  18
  19/* i386 protocol version */
  20#pragma pack(push, 4)
  21struct blkif_x86_32_request {
  22        uint8_t        operation;    /* BLKIF_OP_???                         */
  23        uint8_t        nr_segments;  /* number of segments                   */
  24        blkif_vdev_t   handle;       /* only for read/write requests         */
  25        uint64_t       id;           /* private guest value, echoed in resp  */
  26        blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
  27        struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  28};
  29struct blkif_x86_32_response {
  30        uint64_t        id;              /* copied from request */
  31        uint8_t         operation;       /* copied from request */
  32        int16_t         status;          /* BLKIF_RSP_???       */
  33};
  34typedef struct blkif_x86_32_request blkif_x86_32_request_t;
  35typedef struct blkif_x86_32_response blkif_x86_32_response_t;
  36#pragma pack(pop)
  37
  38/* x86_64 protocol version */
  39struct blkif_x86_64_request {
  40        uint8_t        operation;    /* BLKIF_OP_???                         */
  41        uint8_t        nr_segments;  /* number of segments                   */
  42        blkif_vdev_t   handle;       /* only for read/write requests         */
  43        uint64_t       __attribute__((__aligned__(8))) id;
  44        blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
  45        struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  46};
  47struct blkif_x86_64_response {
  48        uint64_t       __attribute__((__aligned__(8))) id;
  49        uint8_t         operation;       /* copied from request */
  50        int16_t         status;          /* BLKIF_RSP_???       */
  51};
  52typedef struct blkif_x86_64_request blkif_x86_64_request_t;
  53typedef struct blkif_x86_64_response blkif_x86_64_response_t;
  54
  55DEFINE_RING_TYPES(blkif_common, struct blkif_common_request, struct blkif_common_response);
  56DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request, struct blkif_x86_32_response);
  57DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request, struct blkif_x86_64_response);
  58
  59union blkif_back_rings {
  60        blkif_back_ring_t        native;
  61        blkif_common_back_ring_t common;
  62        blkif_x86_32_back_ring_t x86_32_part;
  63        blkif_x86_64_back_ring_t x86_64_part;
  64};
  65typedef union blkif_back_rings blkif_back_rings_t;
  66
  67enum blkif_protocol {
  68        BLKIF_PROTOCOL_NATIVE = 1,
  69        BLKIF_PROTOCOL_X86_32 = 2,
  70        BLKIF_PROTOCOL_X86_64 = 3,
  71};
  72
  73static inline void blkif_get_x86_32_req(blkif_request_t *dst, blkif_x86_32_request_t *src)
  74{
  75        int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
  76
  77        dst->operation = src->operation;
  78        dst->nr_segments = src->nr_segments;
  79        dst->handle = src->handle;
  80        dst->id = src->id;
  81        dst->sector_number = src->sector_number;
  82        if (src->operation == BLKIF_OP_DISCARD) {
  83                struct blkif_request_discard *s = (void *)src;
  84                struct blkif_request_discard *d = (void *)dst;
  85                d->nr_sectors = s->nr_sectors;
  86                return;
  87        }
  88        /* prevent the compiler from optimizing the code and using src->nr_segments instead */
  89        barrier();
  90        if (n > dst->nr_segments)
  91                n = dst->nr_segments;
  92        for (i = 0; i < n; i++)
  93                dst->seg[i] = src->seg[i];
  94}
  95
  96static inline void blkif_get_x86_64_req(blkif_request_t *dst, blkif_x86_64_request_t *src)
  97{
  98        int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
  99
 100        dst->operation = src->operation;
 101        dst->nr_segments = src->nr_segments;
 102        dst->handle = src->handle;
 103        dst->id = src->id;
 104        dst->sector_number = src->sector_number;
 105        if (src->operation == BLKIF_OP_DISCARD) {
 106                struct blkif_request_discard *s = (void *)src;
 107                struct blkif_request_discard *d = (void *)dst;
 108                d->nr_sectors = s->nr_sectors;
 109                return;
 110        }
 111        /* prevent the compiler from optimizing the code and using src->nr_segments instead */
 112        barrier();
 113        if (n > dst->nr_segments)
 114                n = dst->nr_segments;
 115        for (i = 0; i < n; i++)
 116                dst->seg[i] = src->seg[i];
 117}
 118
 119#endif /* __XEN_BLKIF_H__ */
 120