LXR qemu/hw/block/xen

   1#ifndef XEN_BLKIF_H
   2#define XEN_BLKIF_H
   3
   4#include "hw/xen/interface/io/blkif.h"
   5#include "hw/xen/interface/io/protocols.h"
   6
   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.
  12 */
  13struct blkif_common_request {
  14    char dummy;
  15};
  16struct blkif_common_response {
  17    char dummy;
  18};
  19
  20/* i386 protocol version */
  21#pragma pack(push, 4)
  22struct blkif_x86_32_request {
  23    uint8_t        operation;        /* BLKIF_OP_???                         */
  24    uint8_t        nr_segments;      /* number of segments                   */
  25    blkif_vdev_t   handle;           /* only for read/write requests         */
  26    uint64_t       id;               /* private guest value, echoed in resp  */
  27    blkif_sector_t sector_number;    /* start sector idx on disk (r/w only)  */
  28    struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  29};
  30struct blkif_x86_32_request_discard {
  31    uint8_t        operation;        /* BLKIF_OP_DISCARD                     */
  32    uint8_t        flag;             /* nr_segments in request struct        */
  33    blkif_vdev_t   handle;           /* only for read/write requests         */
  34    uint64_t       id;               /* private guest value, echoed in resp  */
  35    blkif_sector_t sector_number;    /* start sector idx on disk (r/w only)  */
  36    uint64_t       nr_sectors;       /* # of contiguous sectors to discard   */
  37};
  38struct blkif_x86_32_response {
  39    uint64_t        id;              /* copied from request */
  40    uint8_t         operation;       /* copied from request */
  41    int16_t         status;          /* BLKIF_RSP_???       */
  42};
  43typedef struct blkif_x86_32_request blkif_x86_32_request_t;
  44typedef struct blkif_x86_32_response blkif_x86_32_response_t;
  45#pragma pack(pop)
  46
  47/* x86_64 protocol version */
  48struct blkif_x86_64_request {
  49    uint8_t        operation;        /* BLKIF_OP_???                         */
  50    uint8_t        nr_segments;      /* number of segments                   */
  51    blkif_vdev_t   handle;           /* only for read/write requests         */
  52    uint64_t       __attribute__((__aligned__(8))) id;
  53    blkif_sector_t sector_number;    /* start sector idx on disk (r/w only)  */
  54    struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  55};
  56struct blkif_x86_64_request_discard {
  57    uint8_t        operation;        /* BLKIF_OP_DISCARD                     */
  58    uint8_t        flag;             /* nr_segments in request struct        */
  59    blkif_vdev_t   handle;           /* only for read/write requests         */
  60    uint64_t       __attribute__((__aligned__(8))) id;
  61    blkif_sector_t sector_number;    /* start sector idx on disk (r/w only)  */
  62    uint64_t       nr_sectors;       /* # of contiguous sectors to discard   */
  63};
  64struct blkif_x86_64_response {
  65    uint64_t       __attribute__((__aligned__(8))) id;
  66    uint8_t         operation;       /* copied from request */
  67    int16_t         status;          /* BLKIF_RSP_???       */
  68};
  69typedef struct blkif_x86_64_request blkif_x86_64_request_t;
  70typedef struct blkif_x86_64_response blkif_x86_64_response_t;
  71
  72DEFINE_RING_TYPES(blkif_common, struct blkif_common_request,
  73                  struct blkif_common_response);
  74DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request,
  75                  struct blkif_x86_32_response);
  76DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request,
  77                  struct blkif_x86_64_response);
  78
  79union blkif_back_rings {
  80    blkif_back_ring_t        native;
  81    blkif_common_back_ring_t common;
  82    blkif_x86_32_back_ring_t x86_32_part;
  83    blkif_x86_64_back_ring_t x86_64_part;
  84};
  85typedef union blkif_back_rings blkif_back_rings_t;
  86
  87enum blkif_protocol {
  88    BLKIF_PROTOCOL_NATIVE = 1,
  89    BLKIF_PROTOCOL_X86_32 = 2,
  90    BLKIF_PROTOCOL_X86_64 = 3,
  91};
  92
  93static inline void blkif_get_x86_32_req(blkif_request_t *dst,
  94                                        blkif_x86_32_request_t *src)
  95{
  96    int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
  97
  98    dst->operation = src->operation;
  99    dst->nr_segments = src->nr_segments;
 100    dst->handle = src->handle;
 101    dst->id = src->id;
 102    dst->sector_number = src->sector_number;
 103    /* Prevent the compiler from using src->... instead. */
 104    barrier();
 105    if (dst->operation == BLKIF_OP_DISCARD) {
 106        struct blkif_x86_32_request_discard *s = (void *)src;
 107        struct blkif_request_discard *d = (void *)dst;
 108        d->nr_sectors = s->nr_sectors;
 109        return;
 110    }
 111    if (n > dst->nr_segments) {
 112        n = dst->nr_segments;
 113    }
 114    for (i = 0; i < n; i++) {
 115        dst->seg[i] = src->seg[i];
 116    }
 117}
 118
 119static inline void blkif_get_x86_64_req(blkif_request_t *dst,
 120                                        blkif_x86_64_request_t *src)
 121{
 122    int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
 123
 124    dst->operation = src->operation;
 125    dst->nr_segments = src->nr_segments;
 126    dst->handle = src->handle;
 127    dst->id = src->id;
 128    dst->sector_number = src->sector_number;
 129    /* Prevent the compiler from using src->... instead. */
 130    barrier();
 131    if (dst->operation == BLKIF_OP_DISCARD) {
 132        struct blkif_x86_64_request_discard *s = (void *)src;
 133        struct blkif_request_discard *d = (void *)dst;
 134        d->nr_sectors = s->nr_sectors;
 135        return;
 136    }
 137    if (n > dst->nr_segments) {
 138        n = dst->nr_segments;
 139    }
 140    for (i = 0; i < n; i++) {
 141        dst->seg[i] = src->seg[i];
 142    }
 143}
 144
 145#define XEN_BLKIF_SECTOR_SIZE 512
 146
 147#endif /* XEN_BLKIF_H */
 148