hw/block/xen_blkif.h

   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  */
  13 struct blkif_common_request {
  14     char dummy;
  15 };
  16 struct blkif_common_response {
  17     char dummy;
  18 };
  19
  20 /* i386 protocol version */
  21 #pragma pack(push, 4)
  22 struct 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 };
  30 struct 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 };
  38 struct 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 };
  43 typedef struct blkif_x86_32_request blkif_x86_32_request_t;
  44 typedef struct blkif_x86_32_response blkif_x86_32_response_t;
  45 #pragma pack(pop)
  46
  47 /* x86_64 protocol version */
  48 struct 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 };
  56 struct 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 };
  64 struct 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 };
  69 typedef struct blkif_x86_64_request blkif_x86_64_request_t;
  70 typedef struct blkif_x86_64_response blkif_x86_64_response_t;
  71
  72 DEFINE_RING_TYPES(blkif_common, struct blkif_common_request,
  73                   struct blkif_common_response);
  74 DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request,
  75                   struct blkif_x86_32_response);
  76 DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request,
  77                   struct blkif_x86_64_response);
  78
  79 union 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 };
  85 typedef union blkif_back_rings blkif_back_rings_t;
  86
  87 enum blkif_protocol {
  88     BLKIF_PROTOCOL_NATIVE = 1,
  89     BLKIF_PROTOCOL_X86_32 = 2,
  90     BLKIF_PROTOCOL_X86_64 = 3,
  91 };
  92
  93 static 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
 119 static 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 */