LXR qemu/hw/block/xen

   1#ifndef XEN_BLKIF_H
   2#define XEN_BLKIF_H
   3
   4#include "hw/xen/io/ring.h"
   5#include <xen/io/blkif.h>
   6#include <xen/io/protocols.h>
   7
   8/*
   9 * Not a real protocol.  Used to generate ring structs which contain
  10 * the elements common to all protocols only.  This way we get a
  11 * compiler-checkable way to use common struct elements, so we can
  12 * avoid using switch(protocol) in a number of places.
  13 */
  14struct blkif_common_request {
  15    char dummy;
  16};
  17struct blkif_common_response {
  18    char dummy;
  19};
  20
  21/* i386 protocol version */
  22#pragma pack(push, 4)
  23struct blkif_x86_32_request {
  24    uint8_t        operation;        /* BLKIF_OP_???                         */
  25    uint8_t        nr_segments;      /* number of segments                   */
  26    blkif_vdev_t   handle;           /* only for read/write requests         */
  27    uint64_t       id;               /* private guest value, echoed in resp  */
  28    blkif_sector_t sector_number;    /* start sector idx on disk (r/w only)  */
  29    struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  30};
  31struct blkif_x86_32_request_discard {
  32    uint8_t        operation;        /* BLKIF_OP_DISCARD                     */
  33    uint8_t        flag;             /* nr_segments in request struct        */
  34    blkif_vdev_t   handle;           /* only for read/write requests         */
  35    uint64_t       id;               /* private guest value, echoed in resp  */
  36    blkif_sector_t sector_number;    /* start sector idx on disk (r/w only)  */
  37    uint64_t       nr_sectors;       /* # of contiguous sectors to discard   */
  38};
  39struct blkif_x86_32_response {
  40    uint64_t        id;              /* copied from request */
  41    uint8_t         operation;       /* copied from request */
  42    int16_t         status;          /* BLKIF_RSP_???       */
  43};
  44typedef struct blkif_x86_32_request blkif_x86_32_request_t;
  45typedef struct blkif_x86_32_response blkif_x86_32_response_t;
  46#pragma pack(pop)
  47
  48/* x86_64 protocol version */
  49struct blkif_x86_64_request {
  50    uint8_t        operation;        /* BLKIF_OP_???                         */
  51    uint8_t        nr_segments;      /* number of segments                   */
  52    blkif_vdev_t   handle;           /* only for read/write requests         */
  53    uint64_t       __attribute__((__aligned__(8))) id;
  54    blkif_sector_t sector_number;    /* start sector idx on disk (r/w only)  */
  55    struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  56};
  57struct blkif_x86_64_request_discard {
  58    uint8_t        operation;        /* BLKIF_OP_DISCARD                     */
  59    uint8_t        flag;             /* nr_segments in request struct        */
  60    blkif_vdev_t   handle;           /* only for read/write requests         */
  61    uint64_t       __attribute__((__aligned__(8))) id;
  62    blkif_sector_t sector_number;    /* start sector idx on disk (r/w only)  */
  63    uint64_t       nr_sectors;       /* # of contiguous sectors to discard   */
  64};
  65struct blkif_x86_64_response {
  66    uint64_t       __attribute__((__aligned__(8))) id;
  67    uint8_t         operation;       /* copied from request */
  68    int16_t         status;          /* BLKIF_RSP_???       */
  69};
  70typedef struct blkif_x86_64_request blkif_x86_64_request_t;
  71typedef struct blkif_x86_64_response blkif_x86_64_response_t;
  72
  73DEFINE_RING_TYPES(blkif_common, struct blkif_common_request,
  74                  struct blkif_common_response);
  75DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request,
  76                  struct blkif_x86_32_response);
  77DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request,
  78                  struct blkif_x86_64_response);
  79
  80union blkif_back_rings {
  81    blkif_back_ring_t        native;
  82    blkif_common_back_ring_t common;
  83    blkif_x86_32_back_ring_t x86_32_part;
  84    blkif_x86_64_back_ring_t x86_64_part;
  85};
  86typedef union blkif_back_rings blkif_back_rings_t;
  87
  88enum blkif_protocol {
  89    BLKIF_PROTOCOL_NATIVE = 1,
  90    BLKIF_PROTOCOL_X86_32 = 2,
  91    BLKIF_PROTOCOL_X86_64 = 3,
  92};
  93
  94static inline void blkif_get_x86_32_req(blkif_request_t *dst,
  95                                        blkif_x86_32_request_t *src)
  96{
  97    int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
  98
  99    dst->operation = src->operation;
 100    dst->nr_segments = src->nr_segments;
 101    dst->handle = src->handle;
 102    dst->id = src->id;
 103    dst->sector_number = src->sector_number;
 104    /* Prevent the compiler from using src->... instead. */
 105    barrier();
 106    if (dst->operation == BLKIF_OP_DISCARD) {
 107        struct blkif_x86_32_request_discard *s = (void *)src;
 108        struct blkif_request_discard *d = (void *)dst;
 109        d->nr_sectors = s->nr_sectors;
 110        return;
 111    }
 112    if (n > dst->nr_segments) {
 113        n = dst->nr_segments;
 114    }
 115    for (i = 0; i < n; i++) {
 116        dst->seg[i] = src->seg[i];
 117    }
 118}
 119
 120static inline void blkif_get_x86_64_req(blkif_request_t *dst,
 121                                        blkif_x86_64_request_t *src)
 122{
 123    int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
 124
 125    dst->operation = src->operation;
 126    dst->nr_segments = src->nr_segments;
 127    dst->handle = src->handle;
 128    dst->id = src->id;
 129    dst->sector_number = src->sector_number;
 130    /* Prevent the compiler from using src->... instead. */
 131    barrier();
 132    if (dst->operation == BLKIF_OP_DISCARD) {
 133        struct blkif_x86_64_request_discard *s = (void *)src;
 134        struct blkif_request_discard *d = (void *)dst;
 135        d->nr_sectors = s->nr_sectors;
 136        return;
 137    }
 138    if (n > dst->nr_segments) {
 139        n = dst->nr_segments;
 140    }
 141    for (i = 0; i < n; i++) {
 142        dst->seg[i] = src->seg[i];
 143    }
 144}
 145
 146#endif /* XEN_BLKIF_H */
 147