hw/virtio-blk.c

   1 /*
   2  * Virtio Block Device
   3  *
   4  * Copyright IBM, Corp. 2007
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #include <qemu-common.h>
  15 #include <sysemu.h>
  16 #include "virtio-blk.h"
  17 #include "block_int.h"
  18
  19 typedef struct VirtIOBlock
  20 {
  21     VirtIODevice vdev;
  22     BlockDriverState *bs;
  23     VirtQueue *vq;
  24     void *rq;
  25 } VirtIOBlock;
  26
  27 static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)
  28 {
  29     return (VirtIOBlock *)vdev;
  30 }
  31
  32 typedef struct VirtIOBlockReq
  33 {
  34     VirtIOBlock *dev;
  35     VirtQueueElement elem;
  36     struct virtio_blk_inhdr *in;
  37     struct virtio_blk_outhdr *out;
  38     QEMUIOVector qiov;
  39     struct VirtIOBlockReq *next;
  40 } VirtIOBlockReq;
  41
  42 static void virtio_blk_req_complete(VirtIOBlockReq *req, int status)
  43 {
  44     VirtIOBlock *s = req->dev;
  45
  46     req->in->status = status;
  47     virtqueue_push(s->vq, &req->elem, req->qiov.size + sizeof(*req->in));
  48     virtio_notify(&s->vdev, s->vq);
  49
  50     qemu_free(req);
  51 }
  52
  53 static int virtio_blk_handle_write_error(VirtIOBlockReq *req, int error)
  54 {
  55     BlockInterfaceErrorAction action = drive_get_onerror(req->dev->bs);
  56     VirtIOBlock *s = req->dev;
  57
  58     if (action == BLOCK_ERR_IGNORE)
  59         return 0;
  60
  61     if ((error == ENOSPC && action == BLOCK_ERR_STOP_ENOSPC)
  62             || action == BLOCK_ERR_STOP_ANY) {
  63         req->next = s->rq;
  64         s->rq = req;
  65         vm_stop(0);
  66     } else {
  67         virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
  68     }
  69
  70     return 1;
  71 }
  72
  73 static void virtio_blk_rw_complete(void *opaque, int ret)
  74 {
  75     VirtIOBlockReq *req = opaque;
  76
  77     if (ret && (req->out->type & VIRTIO_BLK_T_OUT)) {
  78         if (virtio_blk_handle_write_error(req, -ret))
  79             return;
  80     }
  81
  82     virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
  83 }
  84
  85 static VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s)
  86 {
  87     VirtIOBlockReq *req = qemu_mallocz(sizeof(*req));
  88     req->dev = s;
  89     return req;
  90 }
  91
  92 static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s)
  93 {
  94     VirtIOBlockReq *req = virtio_blk_alloc_request(s);
  95
  96     if (req != NULL) {
  97         if (!virtqueue_pop(s->vq, &req->elem)) {
  98             qemu_free(req);
  99             return NULL;
 100         }
 101     }
 102
 103     return req;
 104 }
 105
 106 static void virtio_blk_handle_write(VirtIOBlockReq *req)
 107 {
 108     bdrv_aio_writev(req->dev->bs, req->out->sector, &req->qiov,
 109                     req->qiov.size / 512, virtio_blk_rw_complete, req);
 110 }
 111
 112 static void virtio_blk_handle_read(VirtIOBlockReq *req)
 113 {
 114     bdrv_aio_readv(req->dev->bs, req->out->sector, &req->qiov,
 115                    req->qiov.size / 512, virtio_blk_rw_complete, req);
 116 }
 117
 118 static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 119 {
 120     VirtIOBlock *s = to_virtio_blk(vdev);
 121     VirtIOBlockReq *req;
 122
 123     while ((req = virtio_blk_get_request(s))) {
 124         if (req->elem.out_num < 1 || req->elem.in_num < 1) {
 125             fprintf(stderr, "virtio-blk missing headers\n");
 126             exit(1);
 127         }
 128
 129         if (req->elem.out_sg[0].iov_len < sizeof(*req->out) ||
 130             req->elem.in_sg[req->elem.in_num - 1].iov_len < sizeof(*req->in)) {
 131             fprintf(stderr, "virtio-blk header not in correct element\n");
 132             exit(1);
 133         }
 134
 135         req->out = (void *)req->elem.out_sg[0].iov_base;
 136         req->in = (void *)req->elem.in_sg[req->elem.in_num - 1].iov_base;
 137
 138         if (req->out->type & VIRTIO_BLK_T_SCSI_CMD) {
 139             unsigned int len = sizeof(*req->in);
 140
 141             req->in->status = VIRTIO_BLK_S_UNSUPP;
 142             virtqueue_push(vq, &req->elem, len);
 143             virtio_notify(vdev, vq);
 144             qemu_free(req);
 145         } else if (req->out->type & VIRTIO_BLK_T_OUT) {
 146             qemu_iovec_init_external(&req->qiov, &req->elem.out_sg[1],
 147                                      req->elem.out_num - 1);
 148             virtio_blk_handle_write(req);
 149         } else {
 150             qemu_iovec_init_external(&req->qiov, &req->elem.in_sg[0],
 151                                      req->elem.in_num - 1);
 152             virtio_blk_handle_read(req);
 153         }
 154     }
 155     /*
 156      * FIXME: Want to check for completions before returning to guest mode,
 157      * so cached reads and writes are reported as quickly as possible. But
 158      * that should be done in the generic block layer.
 159      */
 160 }
 161
 162 static void virtio_blk_dma_restart_cb(void *opaque, int running, int reason)
 163 {
 164     VirtIOBlock *s = opaque;
 165     VirtIOBlockReq *req = s->rq;
 166
 167     if (!running)
 168         return;
 169
 170     s->rq = NULL;
 171
 172     while (req) {
 173         virtio_blk_handle_write(req);
 174         req = req->next;
 175     }
 176 }
 177
 178 static void virtio_blk_reset(VirtIODevice *vdev)
 179 {
 180     /*
 181      * This should cancel pending requests, but can't do nicely until there
 182      * are per-device request lists.
 183      */
 184     qemu_aio_flush();
 185 }
 186
 187 static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config)
 188 {
 189     VirtIOBlock *s = to_virtio_blk(vdev);
 190     struct virtio_blk_config blkcfg;
 191     uint64_t capacity;
 192     int cylinders, heads, secs;
 193
 194     bdrv_get_geometry(s->bs, &capacity);
 195     bdrv_get_geometry_hint(s->bs, &cylinders, &heads, &secs);
 196     stq_raw(&blkcfg.capacity, capacity);
 197     stl_raw(&blkcfg.seg_max, 128 - 2);
 198     stw_raw(&blkcfg.cylinders, cylinders);
 199     blkcfg.heads = heads;
 200     blkcfg.sectors = secs;
 201     memcpy(config, &blkcfg, sizeof(blkcfg));
 202 }
 203
 204 static uint32_t virtio_blk_get_features(VirtIODevice *vdev)
 205 {
 206     return (1 << VIRTIO_BLK_F_SEG_MAX | 1 << VIRTIO_BLK_F_GEOMETRY);
 207 }
 208
 209 static void virtio_blk_save(QEMUFile *f, void *opaque)
 210 {
 211     VirtIOBlock *s = opaque;
 212     VirtIOBlockReq *req = s->rq;
 213
 214     virtio_save(&s->vdev, f);
 215
 216     while (req) {
 217         qemu_put_sbyte(f, 1);
 218         qemu_put_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem));
 219         req = req->next;
 220     }
 221     qemu_put_sbyte(f, 0);
 222 }
 223
 224 static int virtio_blk_load(QEMUFile *f, void *opaque, int version_id)
 225 {
 226     VirtIOBlock *s = opaque;
 227
 228     if (version_id != 2)
 229         return -EINVAL;
 230
 231     virtio_load(&s->vdev, f);
 232     while (qemu_get_sbyte(f)) {
 233         VirtIOBlockReq *req = virtio_blk_alloc_request(s);
 234         qemu_get_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem));
 235         req->next = s->rq;
 236         s->rq = req->next;
 237     }
 238
 239     return 0;
 240 }
 241
 242 void *virtio_blk_init(PCIBus *bus, BlockDriverState *bs)
 243 {
 244     VirtIOBlock *s;
 245     int cylinders, heads, secs;
 246     static int virtio_blk_id;
 247
 248     s = (VirtIOBlock *)virtio_init_pci(bus, "virtio-blk",
 249                                        PCI_VENDOR_ID_REDHAT_QUMRANET,
 250                                        PCI_DEVICE_ID_VIRTIO_BLOCK,
 251                                        PCI_VENDOR_ID_REDHAT_QUMRANET,
 252                                        VIRTIO_ID_BLOCK,
 253                                        PCI_CLASS_STORAGE_OTHER, 0x00,
 254                                        sizeof(struct virtio_blk_config), sizeof(VirtIOBlock));
 255     if (!s)
 256         return NULL;
 257
 258     s->vdev.get_config = virtio_blk_update_config;
 259     s->vdev.get_features = virtio_blk_get_features;
 260     s->vdev.reset = virtio_blk_reset;
 261     s->bs = bs;
 262     s->rq = NULL;
 263     bs->private = &s->vdev.pci_dev;
 264     bdrv_guess_geometry(s->bs, &cylinders, &heads, &secs);
 265     bdrv_set_geometry_hint(s->bs, cylinders, heads, secs);
 266
 267     s->vq = virtio_add_queue(&s->vdev, 128, virtio_blk_handle_output);
 268
 269     qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s);
 270     register_savevm("virtio-blk", virtio_blk_id++, 2,
 271                     virtio_blk_save, virtio_blk_load, s);
 272
 273     return s;
 274 }