hw/block/xen_disk.c

   1 /*
   2  *  xen paravirt block device backend
   3  *
   4  *  (c) Gerd Hoffmann <[email protected]>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; under version 2 of the License.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License along
  16  *  with this program; if not, see <http://www.gnu.org/licenses/>.
  17  *
  18  *  Contributions after 2012-01-13 are licensed under the terms of the
  19  *  GNU GPL, version 2 or (at your option) any later version.
  20  */
  21
  22 #include "qemu/osdep.h"
  23 #include <sys/ioctl.h>
  24 #include <sys/uio.h>
  25
  26 #include "hw/hw.h"
  27 #include "hw/xen/xen_backend.h"
  28 #include "xen_blkif.h"
  29 #include "sysemu/blockdev.h"
  30 #include "sysemu/block-backend.h"
  31 #include "qapi/error.h"
  32 #include "qapi/qmp/qdict.h"
  33 #include "qapi/qmp/qstring.h"
  34
  35 /* ------------------------------------------------------------- */
  36
  37 static int batch_maps   = 0;
  38
  39 static int max_requests = 32;
  40
  41 /* ------------------------------------------------------------- */
  42
  43 #define BLOCK_SIZE  512
  44 #define IOCB_COUNT  (BLKIF_MAX_SEGMENTS_PER_REQUEST + 2)
  45
  46 struct PersistentGrant {
  47     void *page;
  48     struct XenBlkDev *blkdev;
  49 };
  50
  51 typedef struct PersistentGrant PersistentGrant;
  52
  53 struct PersistentRegion {
  54     void *addr;
  55     int num;
  56 };
  57
  58 typedef struct PersistentRegion PersistentRegion;
  59
  60 struct ioreq {
  61     blkif_request_t     req;
  62     int16_t             status;
  63
  64     /* parsed request */
  65     off_t               start;
  66     QEMUIOVector        v;
  67     int                 presync;
  68     uint8_t             mapped;
  69
  70     /* grant mapping */
  71     uint32_t            domids[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  72     uint32_t            refs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  73     int                 prot;
  74     void                *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  75     void                *pages;
  76     int                 num_unmap;
  77
  78     /* aio status */
  79     int                 aio_inflight;
  80     int                 aio_errors;
  81
  82     struct XenBlkDev    *blkdev;
  83     QLIST_ENTRY(ioreq)   list;
  84     BlockAcctCookie     acct;
  85 };
  86
  87 struct XenBlkDev {
  88     struct XenDevice    xendev;  /* must be first */
  89     char                *params;
  90     char                *mode;
  91     char                *type;
  92     char                *dev;
  93     char                *devtype;
  94     bool                directiosafe;
  95     const char          *fileproto;
  96     const char          *filename;
  97     int                 ring_ref;
  98     void                *sring;
  99     int64_t             file_blk;
 100     int64_t             file_size;
 101     int                 protocol;
 102     blkif_back_rings_t  rings;
 103     int                 more_work;
 104     int                 cnt_map;
 105
 106     /* request lists */
 107     QLIST_HEAD(inflight_head, ioreq) inflight;
 108     QLIST_HEAD(finished_head, ioreq) finished;
 109     QLIST_HEAD(freelist_head, ioreq) freelist;
 110     int                 requests_total;
 111     int                 requests_inflight;
 112     int                 requests_finished;
 113
 114     /* Persistent grants extension */
 115     gboolean            feature_discard;
 116     gboolean            feature_persistent;
 117     GTree               *persistent_gnts;
 118     GSList              *persistent_regions;
 119     unsigned int        persistent_gnt_count;
 120     unsigned int        max_grants;
 121
 122     /* Grant copy */
 123     gboolean            feature_grant_copy;
 124
 125     /* qemu block driver */
 126     DriveInfo           *dinfo;
 127     BlockBackend        *blk;
 128     QEMUBH              *bh;
 129 };
 130
 131 /* ------------------------------------------------------------- */
 132
 133 static void ioreq_reset(struct ioreq *ioreq)
 134 {
 135     memset(&ioreq->req, 0, sizeof(ioreq->req));
 136     ioreq->status = 0;
 137     ioreq->start = 0;
 138     ioreq->presync = 0;
 139     ioreq->mapped = 0;
 140
 141     memset(ioreq->domids, 0, sizeof(ioreq->domids));
 142     memset(ioreq->refs, 0, sizeof(ioreq->refs));
 143     ioreq->prot = 0;
 144     memset(ioreq->page, 0, sizeof(ioreq->page));
 145     ioreq->pages = NULL;
 146
 147     ioreq->aio_inflight = 0;
 148     ioreq->aio_errors = 0;
 149
 150     ioreq->blkdev = NULL;
 151     memset(&ioreq->list, 0, sizeof(ioreq->list));
 152     memset(&ioreq->acct, 0, sizeof(ioreq->acct));
 153
 154     qemu_iovec_reset(&ioreq->v);
 155 }
 156
 157 static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
 158 {
 159     uint ua = GPOINTER_TO_UINT(a);
 160     uint ub = GPOINTER_TO_UINT(b);
 161     return (ua > ub) - (ua < ub);
 162 }
 163
 164 static void destroy_grant(gpointer pgnt)
 165 {
 166     PersistentGrant *grant = pgnt;
 167     xengnttab_handle *gnt = grant->blkdev->xendev.gnttabdev;
 168
 169     if (xengnttab_unmap(gnt, grant->page, 1) != 0) {
 170         xen_be_printf(&grant->blkdev->xendev, 0,
 171                       "xengnttab_unmap failed: %s\n",
 172                       strerror(errno));
 173     }
 174     grant->blkdev->persistent_gnt_count--;
 175     xen_be_printf(&grant->blkdev->xendev, 3,
 176                   "unmapped grant %p\n", grant->page);
 177     g_free(grant);
 178 }
 179
 180 static void remove_persistent_region(gpointer data, gpointer dev)
 181 {
 182     PersistentRegion *region = data;
 183     struct XenBlkDev *blkdev = dev;
 184     xengnttab_handle *gnt = blkdev->xendev.gnttabdev;
 185
 186     if (xengnttab_unmap(gnt, region->addr, region->num) != 0) {
 187         xen_be_printf(&blkdev->xendev, 0,
 188                       "xengnttab_unmap region %p failed: %s\n",
 189                       region->addr, strerror(errno));
 190     }
 191     xen_be_printf(&blkdev->xendev, 3,
 192                   "unmapped grant region %p with %d pages\n",
 193                   region->addr, region->num);
 194     g_free(region);
 195 }
 196
 197 static struct ioreq *ioreq_start(struct XenBlkDev *blkdev)
 198 {
 199     struct ioreq *ioreq = NULL;
 200
 201     if (QLIST_EMPTY(&blkdev->freelist)) {
 202         if (blkdev->requests_total >= max_requests) {
 203             goto out;
 204         }
 205         /* allocate new struct */
 206         ioreq = g_malloc0(sizeof(*ioreq));
 207         ioreq->blkdev = blkdev;
 208         blkdev->requests_total++;
 209         qemu_iovec_init(&ioreq->v, BLKIF_MAX_SEGMENTS_PER_REQUEST);
 210     } else {
 211         /* get one from freelist */
 212         ioreq = QLIST_FIRST(&blkdev->freelist);
 213         QLIST_REMOVE(ioreq, list);
 214     }
 215     QLIST_INSERT_HEAD(&blkdev->inflight, ioreq, list);
 216     blkdev->requests_inflight++;
 217
 218 out:
 219     return ioreq;
 220 }
 221
 222 static void ioreq_finish(struct ioreq *ioreq)
 223 {
 224     struct XenBlkDev *blkdev = ioreq->blkdev;
 225
 226     QLIST_REMOVE(ioreq, list);
 227     QLIST_INSERT_HEAD(&blkdev->finished, ioreq, list);
 228     blkdev->requests_inflight--;
 229     blkdev->requests_finished++;
 230 }
 231
 232 static void ioreq_release(struct ioreq *ioreq, bool finish)
 233 {
 234     struct XenBlkDev *blkdev = ioreq->blkdev;
 235
 236     QLIST_REMOVE(ioreq, list);
 237     ioreq_reset(ioreq);
 238     ioreq->blkdev = blkdev;
 239     QLIST_INSERT_HEAD(&blkdev->freelist, ioreq, list);
 240     if (finish) {
 241         blkdev->requests_finished--;
 242     } else {
 243         blkdev->requests_inflight--;
 244     }
 245 }
 246
 247 /*
 248  * translate request into iovec + start offset
 249  * do sanity checks along the way
 250  */
 251 static int ioreq_parse(struct ioreq *ioreq)
 252 {
 253     struct XenBlkDev *blkdev = ioreq->blkdev;
 254     uintptr_t mem;
 255     size_t len;
 256     int i;
 257
 258     xen_be_printf(&blkdev->xendev, 3,
 259                   "op %d, nr %d, handle %d, id %" PRId64 ", sector %" PRId64 "\n",
 260                   ioreq->req.operation, ioreq->req.nr_segments,
 261                   ioreq->req.handle, ioreq->req.id, ioreq->req.sector_number);
 262     switch (ioreq->req.operation) {
 263     case BLKIF_OP_READ:
 264         ioreq->prot = PROT_WRITE; /* to memory */
 265         break;
 266     case BLKIF_OP_FLUSH_DISKCACHE:
 267         ioreq->presync = 1;
 268         if (!ioreq->req.nr_segments) {
 269             return 0;
 270         }
 271         /* fall through */
 272     case BLKIF_OP_WRITE:
 273         ioreq->prot = PROT_READ; /* from memory */
 274         break;
 275     case BLKIF_OP_DISCARD:
 276         return 0;
 277     default:
 278         xen_be_printf(&blkdev->xendev, 0, "error: unknown operation (%d)\n",
 279                       ioreq->req.operation);
 280         goto err;
 281     };
 282
 283     if (ioreq->req.operation != BLKIF_OP_READ && blkdev->mode[0] != 'w') {
 284         xen_be_printf(&blkdev->xendev, 0, "error: write req for ro device\n");
 285         goto err;
 286     }
 287
 288     ioreq->start = ioreq->req.sector_number * blkdev->file_blk;
 289     for (i = 0; i < ioreq->req.nr_segments; i++) {
 290         if (i == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
 291             xen_be_printf(&blkdev->xendev, 0, "error: nr_segments too big\n");
 292             goto err;
 293         }
 294         if (ioreq->req.seg[i].first_sect > ioreq->req.seg[i].last_sect) {
 295             xen_be_printf(&blkdev->xendev, 0, "error: first > last sector\n");
 296             goto err;
 297         }
 298         if (ioreq->req.seg[i].last_sect * BLOCK_SIZE >= XC_PAGE_SIZE) {
 299             xen_be_printf(&blkdev->xendev, 0, "error: page crossing\n");
 300             goto err;
 301         }
 302
 303         ioreq->domids[i] = blkdev->xendev.dom;
 304         ioreq->refs[i]   = ioreq->req.seg[i].gref;
 305
 306         mem = ioreq->req.seg[i].first_sect * blkdev->file_blk;
 307         len = (ioreq->req.seg[i].last_sect - ioreq->req.seg[i].first_sect + 1) * blkdev->file_blk;
 308         qemu_iovec_add(&ioreq->v, (void*)mem, len);
 309     }
 310     if (ioreq->start + ioreq->v.size > blkdev->file_size) {
 311         xen_be_printf(&blkdev->xendev, 0, "error: access beyond end of file\n");
 312         goto err;
 313     }
 314     return 0;
 315
 316 err:
 317     ioreq->status = BLKIF_RSP_ERROR;
 318     return -1;
 319 }
 320
 321 static void ioreq_unmap(struct ioreq *ioreq)
 322 {
 323     xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev;
 324     int i;
 325
 326     if (ioreq->num_unmap == 0 || ioreq->mapped == 0) {
 327         return;
 328     }
 329     if (batch_maps) {
 330         if (!ioreq->pages) {
 331             return;
 332         }
 333         if (xengnttab_unmap(gnt, ioreq->pages, ioreq->num_unmap) != 0) {
 334             xen_be_printf(&ioreq->blkdev->xendev, 0,
 335                           "xengnttab_unmap failed: %s\n",
 336                           strerror(errno));
 337         }
 338         ioreq->blkdev->cnt_map -= ioreq->num_unmap;
 339         ioreq->pages = NULL;
 340     } else {
 341         for (i = 0; i < ioreq->num_unmap; i++) {
 342             if (!ioreq->page[i]) {
 343                 continue;
 344             }
 345             if (xengnttab_unmap(gnt, ioreq->page[i], 1) != 0) {
 346                 xen_be_printf(&ioreq->blkdev->xendev, 0,
 347                               "xengnttab_unmap failed: %s\n",
 348                               strerror(errno));
 349             }
 350             ioreq->blkdev->cnt_map--;
 351             ioreq->page[i] = NULL;
 352         }
 353     }
 354     ioreq->mapped = 0;
 355 }
 356
 357 static int ioreq_map(struct ioreq *ioreq)
 358 {
 359     xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev;
 360     uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 361     uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 362     void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 363     int i, j, new_maps = 0;
 364     PersistentGrant *grant;
 365     PersistentRegion *region;
 366     /* domids and refs variables will contain the information necessary
 367      * to map the grants that are needed to fulfill this request.
 368      *
 369      * After mapping the needed grants, the page array will contain the
 370      * memory address of each granted page in the order specified in ioreq
 371      * (disregarding if it's a persistent grant or not).
 372      */
 373
 374     if (ioreq->v.niov == 0 || ioreq->mapped == 1) {
 375         return 0;
 376     }
 377     if (ioreq->blkdev->feature_persistent) {
 378         for (i = 0; i < ioreq->v.niov; i++) {
 379             grant = g_tree_lookup(ioreq->blkdev->persistent_gnts,
 380                                     GUINT_TO_POINTER(ioreq->refs[i]));
 381
 382             if (grant != NULL) {
 383                 page[i] = grant->page;
 384                 xen_be_printf(&ioreq->blkdev->xendev, 3,
 385                               "using persistent-grant %" PRIu32 "\n",
 386                               ioreq->refs[i]);
 387             } else {
 388                     /* Add the grant to the list of grants that
 389                      * should be mapped
 390                      */
 391                     domids[new_maps] = ioreq->domids[i];
 392                     refs[new_maps] = ioreq->refs[i];
 393                     page[i] = NULL;
 394                     new_maps++;
 395             }
 396         }
 397         /* Set the protection to RW, since grants may be reused later
 398          * with a different protection than the one needed for this request
 399          */
 400         ioreq->prot = PROT_WRITE | PROT_READ;
 401     } else {
 402         /* All grants in the request should be mapped */
 403         memcpy(refs, ioreq->refs, sizeof(refs));
 404         memcpy(domids, ioreq->domids, sizeof(domids));
 405         memset(page, 0, sizeof(page));
 406         new_maps = ioreq->v.niov;
 407     }
 408
 409     if (batch_maps && new_maps) {
 410         ioreq->pages = xengnttab_map_grant_refs
 411             (gnt, new_maps, domids, refs, ioreq->prot);
 412         if (ioreq->pages == NULL) {
 413             xen_be_printf(&ioreq->blkdev->xendev, 0,
 414                           "can't map %d grant refs (%s, %d maps)\n",
 415                           new_maps, strerror(errno), ioreq->blkdev->cnt_map);
 416             return -1;
 417         }
 418         for (i = 0, j = 0; i < ioreq->v.niov; i++) {
 419             if (page[i] == NULL) {
 420                 page[i] = ioreq->pages + (j++) * XC_PAGE_SIZE;
 421             }
 422         }
 423         ioreq->blkdev->cnt_map += new_maps;
 424     } else if (new_maps)  {
 425         for (i = 0; i < new_maps; i++) {
 426             ioreq->page[i] = xengnttab_map_grant_ref
 427                 (gnt, domids[i], refs[i], ioreq->prot);
 428             if (ioreq->page[i] == NULL) {
 429                 xen_be_printf(&ioreq->blkdev->xendev, 0,
 430                               "can't map grant ref %d (%s, %d maps)\n",
 431                               refs[i], strerror(errno), ioreq->blkdev->cnt_map);
 432                 ioreq->mapped = 1;
 433                 ioreq_unmap(ioreq);
 434                 return -1;
 435             }
 436             ioreq->blkdev->cnt_map++;
 437         }
 438         for (i = 0, j = 0; i < ioreq->v.niov; i++) {
 439             if (page[i] == NULL) {
 440                 page[i] = ioreq->page[j++];
 441             }
 442         }
 443     }
 444     if (ioreq->blkdev->feature_persistent && new_maps != 0 &&
 445         (!batch_maps || (ioreq->blkdev->persistent_gnt_count + new_maps <=
 446         ioreq->blkdev->max_grants))) {
 447         /*
 448          * If we are using persistent grants and batch mappings only
 449          * add the new maps to the list of persistent grants if the whole
 450          * area can be persistently mapped.
 451          */
 452         if (batch_maps) {
 453             region = g_malloc0(sizeof(*region));
 454             region->addr = ioreq->pages;
 455             region->num = new_maps;
 456             ioreq->blkdev->persistent_regions = g_slist_append(
 457                                             ioreq->blkdev->persistent_regions,
 458                                             region);
 459         }
 460         while ((ioreq->blkdev->persistent_gnt_count < ioreq->blkdev->max_grants)
 461               && new_maps) {
 462             /* Go through the list of newly mapped grants and add as many
 463              * as possible to the list of persistently mapped grants.
 464              *
 465              * Since we start at the end of ioreq->page(s), we only need
 466              * to decrease new_maps to prevent this granted pages from
 467              * being unmapped in ioreq_unmap.
 468              */
 469             grant = g_malloc0(sizeof(*grant));
 470             new_maps--;
 471             if (batch_maps) {
 472                 grant->page = ioreq->pages + (new_maps) * XC_PAGE_SIZE;
 473             } else {
 474                 grant->page = ioreq->page[new_maps];
 475             }
 476             grant->blkdev = ioreq->blkdev;
 477             xen_be_printf(&ioreq->blkdev->xendev, 3,
 478                           "adding grant %" PRIu32 " page: %p\n",
 479                           refs[new_maps], grant->page);
 480             g_tree_insert(ioreq->blkdev->persistent_gnts,
 481                           GUINT_TO_POINTER(refs[new_maps]),
 482                           grant);
 483             ioreq->blkdev->persistent_gnt_count++;
 484         }
 485         assert(!batch_maps || new_maps == 0);
 486     }
 487     for (i = 0; i < ioreq->v.niov; i++) {
 488         ioreq->v.iov[i].iov_base += (uintptr_t)page[i];
 489     }
 490     ioreq->mapped = 1;
 491     ioreq->num_unmap = new_maps;
 492     return 0;
 493 }
 494
 495 #if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 480
 496
 497 static void ioreq_free_copy_buffers(struct ioreq *ioreq)
 498 {
 499     int i;
 500
 501     for (i = 0; i < ioreq->v.niov; i++) {
 502         ioreq->page[i] = NULL;
 503     }
 504
 505     qemu_vfree(ioreq->pages);
 506 }
 507
 508 static int ioreq_init_copy_buffers(struct ioreq *ioreq)
 509 {
 510     int i;
 511
 512     if (ioreq->v.niov == 0) {
 513         return 0;
 514     }
 515
 516     ioreq->pages = qemu_memalign(XC_PAGE_SIZE, ioreq->v.niov * XC_PAGE_SIZE);
 517
 518     for (i = 0; i < ioreq->v.niov; i++) {
 519         ioreq->page[i] = ioreq->pages + i * XC_PAGE_SIZE;
 520         ioreq->v.iov[i].iov_base = ioreq->page[i];
 521     }
 522
 523     return 0;
 524 }
 525
 526 static int ioreq_grant_copy(struct ioreq *ioreq)
 527 {
 528     xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev;
 529     xengnttab_grant_copy_segment_t segs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 530     int i, count, rc;
 531     int64_t file_blk = ioreq->blkdev->file_blk;
 532
 533     if (ioreq->v.niov == 0) {
 534         return 0;
 535     }
 536
 537     count = ioreq->v.niov;
 538
 539     for (i = 0; i < count; i++) {
 540         if (ioreq->req.operation == BLKIF_OP_READ) {
 541             segs[i].flags = GNTCOPY_dest_gref;
 542             segs[i].dest.foreign.ref = ioreq->refs[i];
 543             segs[i].dest.foreign.domid = ioreq->domids[i];
 544             segs[i].dest.foreign.offset = ioreq->req.seg[i].first_sect * file_blk;
 545             segs[i].source.virt = ioreq->v.iov[i].iov_base;
 546         } else {
 547             segs[i].flags = GNTCOPY_source_gref;
 548             segs[i].source.foreign.ref = ioreq->refs[i];
 549             segs[i].source.foreign.domid = ioreq->domids[i];
 550             segs[i].source.foreign.offset = ioreq->req.seg[i].first_sect * file_blk;
 551             segs[i].dest.virt = ioreq->v.iov[i].iov_base;
 552         }
 553         segs[i].len = (ioreq->req.seg[i].last_sect
 554                        - ioreq->req.seg[i].first_sect + 1) * file_blk;
 555     }
 556
 557     rc = xengnttab_grant_copy(gnt, count, segs);
 558
 559     if (rc) {
 560         xen_be_printf(&ioreq->blkdev->xendev, 0,
 561                       "failed to copy data %d\n", rc);
 562         ioreq->aio_errors++;
 563         return -1;
 564     }
 565
 566     for (i = 0; i < count; i++) {
 567         if (segs[i].status != GNTST_okay) {
 568             xen_be_printf(&ioreq->blkdev->xendev, 3,
 569                           "failed to copy data %d for gref %d, domid %d\n",
 570                           segs[i].status, ioreq->refs[i], ioreq->domids[i]);
 571             ioreq->aio_errors++;
 572             rc = -1;
 573         }
 574     }
 575
 576     return rc;
 577 }
 578 #else
 579 static void ioreq_free_copy_buffers(struct ioreq *ioreq)
 580 {
 581     abort();
 582 }
 583
 584 static int ioreq_init_copy_buffers(struct ioreq *ioreq)
 585 {
 586     abort();
 587 }
 588
 589 static int ioreq_grant_copy(struct ioreq *ioreq)
 590 {
 591     abort();
 592 }
 593 #endif
 594
 595 static int ioreq_runio_qemu_aio(struct ioreq *ioreq);
 596
 597 static void qemu_aio_complete(void *opaque, int ret)
 598 {
 599     struct ioreq *ioreq = opaque;
 600
 601     if (ret != 0) {
 602         xen_be_printf(&ioreq->blkdev->xendev, 0, "%s I/O error\n",
 603                       ioreq->req.operation == BLKIF_OP_READ ? "read" : "write");
 604         ioreq->aio_errors++;
 605     }
 606
 607     ioreq->aio_inflight--;
 608     if (ioreq->presync) {
 609         ioreq->presync = 0;
 610         ioreq_runio_qemu_aio(ioreq);
 611         return;
 612     }
 613     if (ioreq->aio_inflight > 0) {
 614         return;
 615     }
 616
 617     if (ioreq->blkdev->feature_grant_copy) {
 618         switch (ioreq->req.operation) {
 619         case BLKIF_OP_READ:
 620             /* in case of failure ioreq->aio_errors is increased */
 621             if (ret == 0) {
 622                 ioreq_grant_copy(ioreq);
 623             }
 624             ioreq_free_copy_buffers(ioreq);
 625             break;
 626         case BLKIF_OP_WRITE:
 627         case BLKIF_OP_FLUSH_DISKCACHE:
 628             if (!ioreq->req.nr_segments) {
 629                 break;
 630             }
 631             ioreq_free_copy_buffers(ioreq);
 632             break;
 633         default:
 634             break;
 635         }
 636     }
 637
 638     ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY;
 639     if (!ioreq->blkdev->feature_grant_copy) {
 640         ioreq_unmap(ioreq);
 641     }
 642     ioreq_finish(ioreq);
 643     switch (ioreq->req.operation) {
 644     case BLKIF_OP_WRITE:
 645     case BLKIF_OP_FLUSH_DISKCACHE:
 646         if (!ioreq->req.nr_segments) {
 647             break;
 648         }
 649     case BLKIF_OP_READ:
 650         if (ioreq->status == BLKIF_RSP_OKAY) {
 651             block_acct_done(blk_get_stats(ioreq->blkdev->blk), &ioreq->acct);
 652         } else {
 653             block_acct_failed(blk_get_stats(ioreq->blkdev->blk), &ioreq->acct);
 654         }
 655         break;
 656     case BLKIF_OP_DISCARD:
 657     default:
 658         break;
 659     }
 660     qemu_bh_schedule(ioreq->blkdev->bh);
 661 }
 662
 663 static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
 664 {
 665     struct XenBlkDev *blkdev = ioreq->blkdev;
 666
 667     if (ioreq->blkdev->feature_grant_copy) {
 668         ioreq_init_copy_buffers(ioreq);
 669         if (ioreq->req.nr_segments && (ioreq->req.operation == BLKIF_OP_WRITE ||
 670             ioreq->req.operation == BLKIF_OP_FLUSH_DISKCACHE) &&
 671             ioreq_grant_copy(ioreq)) {
 672                 ioreq_free_copy_buffers(ioreq);
 673                 goto err;
 674         }
 675     } else {
 676         if (ioreq->req.nr_segments && ioreq_map(ioreq)) {
 677             goto err;
 678         }
 679     }
 680
 681     ioreq->aio_inflight++;
 682     if (ioreq->presync) {
 683         blk_aio_flush(ioreq->blkdev->blk, qemu_aio_complete, ioreq);
 684         return 0;
 685     }
 686
 687     switch (ioreq->req.operation) {
 688     case BLKIF_OP_READ:
 689         block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct,
 690                          ioreq->v.size, BLOCK_ACCT_READ);
 691         ioreq->aio_inflight++;
 692         blk_aio_preadv(blkdev->blk, ioreq->start, &ioreq->v, 0,
 693                        qemu_aio_complete, ioreq);
 694         break;
 695     case BLKIF_OP_WRITE:
 696     case BLKIF_OP_FLUSH_DISKCACHE:
 697         if (!ioreq->req.nr_segments) {
 698             break;
 699         }
 700
 701         block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct,
 702                          ioreq->v.size,
 703                          ioreq->req.operation == BLKIF_OP_WRITE ?
 704                          BLOCK_ACCT_WRITE : BLOCK_ACCT_FLUSH);
 705         ioreq->aio_inflight++;
 706         blk_aio_pwritev(blkdev->blk, ioreq->start, &ioreq->v, 0,
 707                         qemu_aio_complete, ioreq);
 708         break;
 709     case BLKIF_OP_DISCARD:
 710     {
 711         struct blkif_request_discard *discard_req = (void *)&ioreq->req;
 712         ioreq->aio_inflight++;
 713         blk_aio_pdiscard(blkdev->blk,
 714                          discard_req->sector_number << BDRV_SECTOR_BITS,
 715                          discard_req->nr_sectors << BDRV_SECTOR_BITS,
 716                          qemu_aio_complete, ioreq);
 717         break;
 718     }
 719     default:
 720         /* unknown operation (shouldn't happen -- parse catches this) */
 721         if (!ioreq->blkdev->feature_grant_copy) {
 722             ioreq_unmap(ioreq);
 723         }
 724         goto err;
 725     }
 726
 727     qemu_aio_complete(ioreq, 0);
 728
 729     return 0;
 730
 731 err:
 732     ioreq_finish(ioreq);
 733     ioreq->status = BLKIF_RSP_ERROR;
 734     return -1;
 735 }
 736
 737 static int blk_send_response_one(struct ioreq *ioreq)
 738 {
 739     struct XenBlkDev  *blkdev = ioreq->blkdev;
 740     int               send_notify   = 0;
 741     int               have_requests = 0;
 742     blkif_response_t  resp;
 743     void              *dst;
 744
 745     resp.id        = ioreq->req.id;
 746     resp.operation = ioreq->req.operation;
 747     resp.status    = ioreq->status;
 748
 749     /* Place on the response ring for the relevant domain. */
 750     switch (blkdev->protocol) {
 751     case BLKIF_PROTOCOL_NATIVE:
 752         dst = RING_GET_RESPONSE(&blkdev->rings.native, blkdev->rings.native.rsp_prod_pvt);
 753         break;
 754     case BLKIF_PROTOCOL_X86_32:
 755         dst = RING_GET_RESPONSE(&blkdev->rings.x86_32_part,
 756                                 blkdev->rings.x86_32_part.rsp_prod_pvt);
 757         break;
 758     case BLKIF_PROTOCOL_X86_64:
 759         dst = RING_GET_RESPONSE(&blkdev->rings.x86_64_part,
 760                                 blkdev->rings.x86_64_part.rsp_prod_pvt);
 761         break;
 762     default:
 763         dst = NULL;
 764         return 0;
 765     }
 766     memcpy(dst, &resp, sizeof(resp));
 767     blkdev->rings.common.rsp_prod_pvt++;
 768
 769     RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blkdev->rings.common, send_notify);
 770     if (blkdev->rings.common.rsp_prod_pvt == blkdev->rings.common.req_cons) {
 771         /*
 772          * Tail check for pending requests. Allows frontend to avoid
 773          * notifications if requests are already in flight (lower
 774          * overheads and promotes batching).
 775          */
 776         RING_FINAL_CHECK_FOR_REQUESTS(&blkdev->rings.common, have_requests);
 777     } else if (RING_HAS_UNCONSUMED_REQUESTS(&blkdev->rings.common)) {
 778         have_requests = 1;
 779     }
 780
 781     if (have_requests) {
 782         blkdev->more_work++;
 783     }
 784     return send_notify;
 785 }
 786
 787 /* walk finished list, send outstanding responses, free requests */
 788 static void blk_send_response_all(struct XenBlkDev *blkdev)
 789 {
 790     struct ioreq *ioreq;
 791     int send_notify = 0;
 792
 793     while (!QLIST_EMPTY(&blkdev->finished)) {
 794         ioreq = QLIST_FIRST(&blkdev->finished);
 795         send_notify += blk_send_response_one(ioreq);
 796         ioreq_release(ioreq, true);
 797     }
 798     if (send_notify) {
 799         xen_be_send_notify(&blkdev->xendev);
 800     }
 801 }
 802
 803 static int blk_get_request(struct XenBlkDev *blkdev, struct ioreq *ioreq, RING_IDX rc)
 804 {
 805     switch (blkdev->protocol) {
 806     case BLKIF_PROTOCOL_NATIVE:
 807         memcpy(&ioreq->req, RING_GET_REQUEST(&blkdev->rings.native, rc),
 808                sizeof(ioreq->req));
 809         break;
 810     case BLKIF_PROTOCOL_X86_32:
 811         blkif_get_x86_32_req(&ioreq->req,
 812                              RING_GET_REQUEST(&blkdev->rings.x86_32_part, rc));
 813         break;
 814     case BLKIF_PROTOCOL_X86_64:
 815         blkif_get_x86_64_req(&ioreq->req,
 816                              RING_GET_REQUEST(&blkdev->rings.x86_64_part, rc));
 817         break;
 818     }
 819     /* Prevent the compiler from accessing the on-ring fields instead. */
 820     barrier();
 821     return 0;
 822 }
 823
 824 static void blk_handle_requests(struct XenBlkDev *blkdev)
 825 {
 826     RING_IDX rc, rp;
 827     struct ioreq *ioreq;
 828
 829     blkdev->more_work = 0;
 830
 831     rc = blkdev->rings.common.req_cons;
 832     rp = blkdev->rings.common.sring->req_prod;
 833     xen_rmb(); /* Ensure we see queued requests up to 'rp'. */
 834
 835     blk_send_response_all(blkdev);
 836     while (rc != rp) {
 837         /* pull request from ring */
 838         if (RING_REQUEST_CONS_OVERFLOW(&blkdev->rings.common, rc)) {
 839             break;
 840         }
 841         ioreq = ioreq_start(blkdev);
 842         if (ioreq == NULL) {
 843             blkdev->more_work++;
 844             break;
 845         }
 846         blk_get_request(blkdev, ioreq, rc);
 847         blkdev->rings.common.req_cons = ++rc;
 848
 849         /* parse them */
 850         if (ioreq_parse(ioreq) != 0) {
 851
 852             switch (ioreq->req.operation) {
 853             case BLKIF_OP_READ:
 854                 block_acct_invalid(blk_get_stats(blkdev->blk),
 855                                    BLOCK_ACCT_READ);
 856                 break;
 857             case BLKIF_OP_WRITE:
 858                 block_acct_invalid(blk_get_stats(blkdev->blk),
 859                                    BLOCK_ACCT_WRITE);
 860                 break;
 861             case BLKIF_OP_FLUSH_DISKCACHE:
 862                 block_acct_invalid(blk_get_stats(blkdev->blk),
 863                                    BLOCK_ACCT_FLUSH);
 864             default:
 865                 break;
 866             };
 867
 868             if (blk_send_response_one(ioreq)) {
 869                 xen_be_send_notify(&blkdev->xendev);
 870             }
 871             ioreq_release(ioreq, false);
 872             continue;
 873         }
 874
 875         ioreq_runio_qemu_aio(ioreq);
 876     }
 877
 878     if (blkdev->more_work && blkdev->requests_inflight < max_requests) {
 879         qemu_bh_schedule(blkdev->bh);
 880     }
 881 }
 882
 883 /* ------------------------------------------------------------- */
 884
 885 static void blk_bh(void *opaque)
 886 {
 887     struct XenBlkDev *blkdev = opaque;
 888     blk_handle_requests(blkdev);
 889 }
 890
 891 /*
 892  * We need to account for the grant allocations requiring contiguous
 893  * chunks; the worst case number would be
 894  *     max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1,
 895  * but in order to keep things simple just use
 896  *     2 * max_req * max_seg.
 897  */
 898 #define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg))
 899
 900 static void blk_alloc(struct XenDevice *xendev)
 901 {
 902     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
 903
 904     QLIST_INIT(&blkdev->inflight);
 905     QLIST_INIT(&blkdev->finished);
 906     QLIST_INIT(&blkdev->freelist);
 907     blkdev->bh = qemu_bh_new(blk_bh, blkdev);
 908     if (xen_mode != XEN_EMULATE) {
 909         batch_maps = 1;
 910     }
 911     if (xengnttab_set_max_grants(xendev->gnttabdev,
 912             MAX_GRANTS(max_requests, BLKIF_MAX_SEGMENTS_PER_REQUEST)) < 0) {
 913         xen_be_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n",
 914                       strerror(errno));
 915     }
 916 }
 917
 918 static void blk_parse_discard(struct XenBlkDev *blkdev)
 919 {
 920     int enable;
 921
 922     blkdev->feature_discard = true;
 923
 924     if (xenstore_read_be_int(&blkdev->xendev, "discard-enable", &enable) == 0) {
 925         blkdev->feature_discard = !!enable;
 926     }
 927
 928     if (blkdev->feature_discard) {
 929         xenstore_write_be_int(&blkdev->xendev, "feature-discard", 1);
 930     }
 931 }
 932
 933 static int blk_init(struct XenDevice *xendev)
 934 {
 935     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
 936     int info = 0;
 937     char *directiosafe = NULL;
 938
 939     /* read xenstore entries */
 940     if (blkdev->params == NULL) {
 941         char *h = NULL;
 942         blkdev->params = xenstore_read_be_str(&blkdev->xendev, "params");
 943         if (blkdev->params != NULL) {
 944             h = strchr(blkdev->params, ':');
 945         }
 946         if (h != NULL) {
 947             blkdev->fileproto = blkdev->params;
 948             blkdev->filename  = h+1;
 949             *h = 0;
 950         } else {
 951             blkdev->fileproto = "<unset>";
 952             blkdev->filename  = blkdev->params;
 953         }
 954     }
 955     if (!strcmp("aio", blkdev->fileproto)) {
 956         blkdev->fileproto = "raw";
 957     }
 958     if (!strcmp("vhd", blkdev->fileproto)) {
 959         blkdev->fileproto = "vpc";
 960     }
 961     if (blkdev->mode == NULL) {
 962         blkdev->mode = xenstore_read_be_str(&blkdev->xendev, "mode");
 963     }
 964     if (blkdev->type == NULL) {
 965         blkdev->type = xenstore_read_be_str(&blkdev->xendev, "type");
 966     }
 967     if (blkdev->dev == NULL) {
 968         blkdev->dev = xenstore_read_be_str(&blkdev->xendev, "dev");
 969     }
 970     if (blkdev->devtype == NULL) {
 971         blkdev->devtype = xenstore_read_be_str(&blkdev->xendev, "device-type");
 972     }
 973     directiosafe = xenstore_read_be_str(&blkdev->xendev, "direct-io-safe");
 974     blkdev->directiosafe = (directiosafe && atoi(directiosafe));
 975
 976     /* do we have all we need? */
 977     if (blkdev->params == NULL ||
 978         blkdev->mode == NULL   ||
 979         blkdev->type == NULL   ||
 980         blkdev->dev == NULL) {
 981         goto out_error;
 982     }
 983
 984     /* read-only ? */
 985     if (strcmp(blkdev->mode, "w")) {
 986         info  |= VDISK_READONLY;
 987     }
 988
 989     /* cdrom ? */
 990     if (blkdev->devtype && !strcmp(blkdev->devtype, "cdrom")) {
 991         info  |= VDISK_CDROM;
 992     }
 993
 994     blkdev->file_blk  = BLOCK_SIZE;
 995
 996     /* fill info
 997      * blk_connect supplies sector-size and sectors
 998      */
 999     xenstore_write_be_int(&blkdev->xendev, "feature-flush-cache", 1);
1000     xenstore_write_be_int(&blkdev->xendev, "feature-persistent", 1);
1001     xenstore_write_be_int(&blkdev->xendev, "info", info);
1002
1003     blk_parse_discard(blkdev);
1004
1005     g_free(directiosafe);
1006     return 0;
1007
1008 out_error:
1009     g_free(blkdev->params);
1010     blkdev->params = NULL;
1011     g_free(blkdev->mode);
1012     blkdev->mode = NULL;
1013     g_free(blkdev->type);
1014     blkdev->type = NULL;
1015     g_free(blkdev->dev);
1016     blkdev->dev = NULL;
1017     g_free(blkdev->devtype);
1018     blkdev->devtype = NULL;
1019     g_free(directiosafe);
1020     blkdev->directiosafe = false;
1021     return -1;
1022 }
1023
1024 static int blk_connect(struct XenDevice *xendev)
1025 {
1026     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
1027     int pers, index, qflags;
1028     bool readonly = true;
1029     bool writethrough = true;
1030
1031     /* read-only ? */
1032     if (blkdev->directiosafe) {
1033         qflags = BDRV_O_NOCACHE | BDRV_O_NATIVE_AIO;
1034     } else {
1035         qflags = 0;
1036         writethrough = false;
1037     }
1038     if (strcmp(blkdev->mode, "w") == 0) {
1039         qflags |= BDRV_O_RDWR;
1040         readonly = false;
1041     }
1042     if (blkdev->feature_discard) {
1043         qflags |= BDRV_O_UNMAP;
1044     }
1045
1046     /* init qemu block driver */
1047     index = (blkdev->xendev.dev - 202 * 256) / 16;
1048     blkdev->dinfo = drive_get(IF_XEN, 0, index);
1049     if (!blkdev->dinfo) {
1050         Error *local_err = NULL;
1051         QDict *options = NULL;
1052
1053         if (strcmp(blkdev->fileproto, "<unset>")) {
1054             options = qdict_new();
1055             qdict_put(options, "driver", qstring_from_str(blkdev->fileproto));
1056         }
1057
1058         /* setup via xenbus -> create new block driver instance */
1059         xen_be_printf(&blkdev->xendev, 2, "create new bdrv (xenbus setup)\n");
1060         blkdev->blk = blk_new_open(blkdev->filename, NULL, options,
1061                                    qflags, &local_err);
1062         if (!blkdev->blk) {
1063             xen_be_printf(&blkdev->xendev, 0, "error: %s\n",
1064                           error_get_pretty(local_err));
1065             error_free(local_err);
1066             return -1;
1067         }
1068         blk_set_enable_write_cache(blkdev->blk, !writethrough);
1069     } else {
1070         /* setup via qemu cmdline -> already setup for us */
1071         xen_be_printf(&blkdev->xendev, 2, "get configured bdrv (cmdline setup)\n");
1072         blkdev->blk = blk_by_legacy_dinfo(blkdev->dinfo);
1073         if (blk_is_read_only(blkdev->blk) && !readonly) {
1074             xen_be_printf(&blkdev->xendev, 0, "Unexpected read-only drive");
1075             blkdev->blk = NULL;
1076             return -1;
1077         }
1078         /* blkdev->blk is not create by us, we get a reference
1079          * so we can blk_unref() unconditionally */
1080         blk_ref(blkdev->blk);
1081     }
1082     blk_attach_dev_nofail(blkdev->blk, blkdev);
1083     blkdev->file_size = blk_getlength(blkdev->blk);
1084     if (blkdev->file_size < 0) {
1085         BlockDriverState *bs = blk_bs(blkdev->blk);
1086         const char *drv_name = bs ? bdrv_get_format_name(bs) : NULL;
1087         xen_be_printf(&blkdev->xendev, 1, "blk_getlength: %d (%s) | drv %s\n",
1088                       (int)blkdev->file_size, strerror(-blkdev->file_size),
1089                       drv_name ?: "-");
1090         blkdev->file_size = 0;
1091     }
1092
1093     xen_be_printf(xendev, 1, "type \"%s\", fileproto \"%s\", filename \"%s\","
1094                   " size %" PRId64 " (%" PRId64 " MB)\n",
1095                   blkdev->type, blkdev->fileproto, blkdev->filename,
1096                   blkdev->file_size, blkdev->file_size >> 20);
1097
1098     /* Fill in number of sector size and number of sectors */
1099     xenstore_write_be_int(&blkdev->xendev, "sector-size", blkdev->file_blk);
1100     xenstore_write_be_int64(&blkdev->xendev, "sectors",
1101                             blkdev->file_size / blkdev->file_blk);
1102
1103     if (xenstore_read_fe_int(&blkdev->xendev, "ring-ref", &blkdev->ring_ref) == -1) {
1104         return -1;
1105     }
1106     if (xenstore_read_fe_int(&blkdev->xendev, "event-channel",
1107                              &blkdev->xendev.remote_port) == -1) {
1108         return -1;
1109     }
1110     if (xenstore_read_fe_int(&blkdev->xendev, "feature-persistent", &pers)) {
1111         blkdev->feature_persistent = FALSE;
1112     } else {
1113         blkdev->feature_persistent = !!pers;
1114     }
1115
1116     if (!blkdev->xendev.protocol) {
1117         blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
1118     } else if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_NATIVE) == 0) {
1119         blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
1120     } else if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_32) == 0) {
1121         blkdev->protocol = BLKIF_PROTOCOL_X86_32;
1122     } else if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_64) == 0) {
1123         blkdev->protocol = BLKIF_PROTOCOL_X86_64;
1124     } else {
1125         blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
1126     }
1127
1128     blkdev->sring = xengnttab_map_grant_ref(blkdev->xendev.gnttabdev,
1129                                             blkdev->xendev.dom,
1130                                             blkdev->ring_ref,
1131                                             PROT_READ | PROT_WRITE);
1132     if (!blkdev->sring) {
1133         return -1;
1134     }
1135     blkdev->cnt_map++;
1136
1137     switch (blkdev->protocol) {
1138     case BLKIF_PROTOCOL_NATIVE:
1139     {
1140         blkif_sring_t *sring_native = blkdev->sring;
1141         BACK_RING_INIT(&blkdev->rings.native, sring_native, XC_PAGE_SIZE);
1142         break;
1143     }
1144     case BLKIF_PROTOCOL_X86_32:
1145     {
1146         blkif_x86_32_sring_t *sring_x86_32 = blkdev->sring;
1147
1148         BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, XC_PAGE_SIZE);
1149         break;
1150     }
1151     case BLKIF_PROTOCOL_X86_64:
1152     {
1153         blkif_x86_64_sring_t *sring_x86_64 = blkdev->sring;
1154
1155         BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, XC_PAGE_SIZE);
1156         break;
1157     }
1158     }
1159
1160     if (blkdev->feature_persistent) {
1161         /* Init persistent grants */
1162         blkdev->max_grants = max_requests * BLKIF_MAX_SEGMENTS_PER_REQUEST;
1163         blkdev->persistent_gnts = g_tree_new_full((GCompareDataFunc)int_cmp,
1164                                              NULL, NULL,
1165                                              batch_maps ?
1166                                              (GDestroyNotify)g_free :
1167                                              (GDestroyNotify)destroy_grant);
1168         blkdev->persistent_regions = NULL;
1169         blkdev->persistent_gnt_count = 0;
1170     }
1171
1172     xen_be_bind_evtchn(&blkdev->xendev);
1173
1174     blkdev->feature_grant_copy =
1175                 (xengnttab_grant_copy(blkdev->xendev.gnttabdev, 0, NULL) == 0);
1176
1177     xen_be_printf(&blkdev->xendev, 3, "grant copy operation %s\n",
1178                   blkdev->feature_grant_copy ? "enabled" : "disabled");
1179
1180     xen_be_printf(&blkdev->xendev, 1, "ok: proto %s, ring-ref %d, "
1181                   "remote port %d, local port %d\n",
1182                   blkdev->xendev.protocol, blkdev->ring_ref,
1183                   blkdev->xendev.remote_port, blkdev->xendev.local_port);
1184     return 0;
1185 }
1186
1187 static void blk_disconnect(struct XenDevice *xendev)
1188 {
1189     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
1190
1191     if (blkdev->blk) {
1192         blk_detach_dev(blkdev->blk, blkdev);
1193         blk_unref(blkdev->blk);
1194         blkdev->blk = NULL;
1195     }
1196     xen_be_unbind_evtchn(&blkdev->xendev);
1197
1198     if (blkdev->sring) {
1199         xengnttab_unmap(blkdev->xendev.gnttabdev, blkdev->sring, 1);
1200         blkdev->cnt_map--;
1201         blkdev->sring = NULL;
1202     }
1203
1204     /*
1205      * Unmap persistent grants before switching to the closed state
1206      * so the frontend can free them.
1207      *
1208      * In the !batch_maps case g_tree_destroy will take care of unmapping
1209      * the grant, but in the batch_maps case we need to iterate over every
1210      * region in persistent_regions and unmap it.
1211      */
1212     if (blkdev->feature_persistent) {
1213         g_tree_destroy(blkdev->persistent_gnts);
1214         assert(batch_maps || blkdev->persistent_gnt_count == 0);
1215         if (batch_maps) {
1216             blkdev->persistent_gnt_count = 0;
1217             g_slist_foreach(blkdev->persistent_regions,
1218                             (GFunc)remove_persistent_region, blkdev);
1219             g_slist_free(blkdev->persistent_regions);
1220         }
1221         blkdev->feature_persistent = false;
1222     }
1223 }
1224
1225 static int blk_free(struct XenDevice *xendev)
1226 {
1227     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
1228     struct ioreq *ioreq;
1229
1230     if (blkdev->blk || blkdev->sring) {
1231         blk_disconnect(xendev);
1232     }
1233
1234     while (!QLIST_EMPTY(&blkdev->freelist)) {
1235         ioreq = QLIST_FIRST(&blkdev->freelist);
1236         QLIST_REMOVE(ioreq, list);
1237         qemu_iovec_destroy(&ioreq->v);
1238         g_free(ioreq);
1239     }
1240
1241     g_free(blkdev->params);
1242     g_free(blkdev->mode);
1243     g_free(blkdev->type);
1244     g_free(blkdev->dev);
1245     g_free(blkdev->devtype);
1246     qemu_bh_delete(blkdev->bh);
1247     return 0;
1248 }
1249
1250 static void blk_event(struct XenDevice *xendev)
1251 {
1252     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
1253
1254     qemu_bh_schedule(blkdev->bh);
1255 }
1256
1257 struct XenDevOps xen_blkdev_ops = {
1258     .size       = sizeof(struct XenBlkDev),
1259     .flags      = DEVOPS_FLAG_NEED_GNTDEV,
1260     .alloc      = blk_alloc,
1261     .init       = blk_init,
1262     .initialise    = blk_connect,
1263     .disconnect = blk_disconnect,
1264     .event      = blk_event,
1265     .free       = blk_free,
1266 };