diff --git a/MAINTAINERS b/MAINTAINERS
index 7514550c06..4c98b34853 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -415,6 +415,7 @@ F: hw/char/xen_console.c
 F: hw/display/xenfb.c
 F: hw/net/xen_nic.c
 F: hw/block/xen*
+F: hw/block/dataplane/xen*
 F: hw/xen/
 F: hw/xenpv/
 F: hw/i386/xen/
diff --git a/hw/block/dataplane/xen-block.c b/hw/block/dataplane/xen-block.c
new file mode 100644
index 0000000000..9fae50534e
--- /dev/null
+++ b/hw/block/dataplane/xen-block.c
@@ -0,0 +1,1019 @@
+/*
+ *  xen paravirt block device backend
+ *
+ *  (c) Gerd Hoffmann <kraxel@redhat.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; under version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Contributions after 2012-01-13 are licensed under the terms of the
+ *  GNU GPL, version 2 or (at your option) any later version.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/units.h"
+#include <sys/ioctl.h>
+#include <sys/uio.h>
+
+#include "hw/hw.h"
+#include "hw/xen/xen_backend.h"
+#include "xen_blkif.h"
+#include "sysemu/blockdev.h"
+#include "sysemu/iothread.h"
+#include "sysemu/block-backend.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qmp/qstring.h"
+#include "trace.h"
+
+/* ------------------------------------------------------------- */
+
+#define BLOCK_SIZE  512
+#define IOCB_COUNT  (BLKIF_MAX_SEGMENTS_PER_REQUEST + 2)
+
+struct ioreq {
+    blkif_request_t     req;
+    int16_t             status;
+
+    /* parsed request */
+    off_t               start;
+    QEMUIOVector        v;
+    void                *buf;
+    size_t              size;
+    int                 presync;
+
+    /* aio status */
+    int                 aio_inflight;
+    int                 aio_errors;
+
+    struct XenBlkDev    *blkdev;
+    QLIST_ENTRY(ioreq)   list;
+    BlockAcctCookie     acct;
+};
+
+#define MAX_RING_PAGE_ORDER 4
+
+struct XenBlkDev {
+    struct XenLegacyDevice    xendev;  /* must be first */
+    char                *params;
+    char                *mode;
+    char                *type;
+    char                *dev;
+    char                *devtype;
+    bool                directiosafe;
+    const char          *fileproto;
+    const char          *filename;
+    unsigned int        ring_ref[1 << MAX_RING_PAGE_ORDER];
+    unsigned int        nr_ring_ref;
+    void                *sring;
+    int64_t             file_blk;
+    int64_t             file_size;
+    int                 protocol;
+    blkif_back_rings_t  rings;
+    int                 more_work;
+
+    /* request lists */
+    QLIST_HEAD(inflight_head, ioreq) inflight;
+    QLIST_HEAD(finished_head, ioreq) finished;
+    QLIST_HEAD(freelist_head, ioreq) freelist;
+    int                 requests_total;
+    int                 requests_inflight;
+    int                 requests_finished;
+    unsigned int        max_requests;
+
+    gboolean            feature_discard;
+
+    /* qemu block driver */
+    DriveInfo           *dinfo;
+    BlockBackend        *blk;
+    QEMUBH              *bh;
+
+    IOThread            *iothread;
+    AioContext          *ctx;
+};
+
+/* ------------------------------------------------------------- */
+
+static void ioreq_reset(struct ioreq *ioreq)
+{
+    memset(&ioreq->req, 0, sizeof(ioreq->req));
+    ioreq->status = 0;
+    ioreq->start = 0;
+    ioreq->buf = NULL;
+    ioreq->size = 0;
+    ioreq->presync = 0;
+
+    ioreq->aio_inflight = 0;
+    ioreq->aio_errors = 0;
+
+    ioreq->blkdev = NULL;
+    memset(&ioreq->list, 0, sizeof(ioreq->list));
+    memset(&ioreq->acct, 0, sizeof(ioreq->acct));
+
+    qemu_iovec_reset(&ioreq->v);
+}
+
+static struct ioreq *ioreq_start(struct XenBlkDev *blkdev)
+{
+    struct ioreq *ioreq = NULL;
+
+    if (QLIST_EMPTY(&blkdev->freelist)) {
+        if (blkdev->requests_total >= blkdev->max_requests) {
+            goto out;
+        }
+        /* allocate new struct */
+        ioreq = g_malloc0(sizeof(*ioreq));
+        ioreq->blkdev = blkdev;
+        blkdev->requests_total++;
+        qemu_iovec_init(&ioreq->v, 1);
+    } else {
+        /* get one from freelist */
+        ioreq = QLIST_FIRST(&blkdev->freelist);
+        QLIST_REMOVE(ioreq, list);
+    }
+    QLIST_INSERT_HEAD(&blkdev->inflight, ioreq, list);
+    blkdev->requests_inflight++;
+
+out:
+    return ioreq;
+}
+
+static void ioreq_finish(struct ioreq *ioreq)
+{
+    struct XenBlkDev *blkdev = ioreq->blkdev;
+
+    QLIST_REMOVE(ioreq, list);
+    QLIST_INSERT_HEAD(&blkdev->finished, ioreq, list);
+    blkdev->requests_inflight--;
+    blkdev->requests_finished++;
+}
+
+static void ioreq_release(struct ioreq *ioreq, bool finish)
+{
+    struct XenBlkDev *blkdev = ioreq->blkdev;
+
+    QLIST_REMOVE(ioreq, list);
+    ioreq_reset(ioreq);
+    ioreq->blkdev = blkdev;
+    QLIST_INSERT_HEAD(&blkdev->freelist, ioreq, list);
+    if (finish) {
+        blkdev->requests_finished--;
+    } else {
+        blkdev->requests_inflight--;
+    }
+}
+
+/*
+ * translate request into iovec + start offset
+ * do sanity checks along the way
+ */
+static int ioreq_parse(struct ioreq *ioreq)
+{
+    struct XenBlkDev *blkdev = ioreq->blkdev;
+    struct XenLegacyDevice *xendev = &blkdev->xendev;
+    size_t len;
+    int i;
+
+    xen_pv_printf(
+        xendev, 3,
+        "op %d, nr %d, handle %d, id %" PRId64 ", sector %" PRId64 "\n",
+        ioreq->req.operation, ioreq->req.nr_segments,
+        ioreq->req.handle, ioreq->req.id, ioreq->req.sector_number);
+    switch (ioreq->req.operation) {
+    case BLKIF_OP_READ:
+        break;
+    case BLKIF_OP_FLUSH_DISKCACHE:
+        ioreq->presync = 1;
+        if (!ioreq->req.nr_segments) {
+            return 0;
+        }
+        /* fall through */
+    case BLKIF_OP_WRITE:
+        break;
+    case BLKIF_OP_DISCARD:
+        return 0;
+    default:
+        xen_pv_printf(xendev, 0, "error: unknown operation (%d)\n",
+                      ioreq->req.operation);
+        goto err;
+    };
+
+    if (ioreq->req.operation != BLKIF_OP_READ && blkdev->mode[0] != 'w') {
+        xen_pv_printf(xendev, 0, "error: write req for ro device\n");
+        goto err;
+    }
+
+    ioreq->start = ioreq->req.sector_number * blkdev->file_blk;
+    for (i = 0; i < ioreq->req.nr_segments; i++) {
+        if (i == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
+            xen_pv_printf(xendev, 0, "error: nr_segments too big\n");
+            goto err;
+        }
+        if (ioreq->req.seg[i].first_sect > ioreq->req.seg[i].last_sect) {
+            xen_pv_printf(xendev, 0, "error: first > last sector\n");
+            goto err;
+        }
+        if (ioreq->req.seg[i].last_sect * BLOCK_SIZE >= XC_PAGE_SIZE) {
+            xen_pv_printf(xendev, 0, "error: page crossing\n");
+            goto err;
+        }
+
+        len = (ioreq->req.seg[i].last_sect -
+               ioreq->req.seg[i].first_sect + 1) * blkdev->file_blk;
+        ioreq->size += len;
+    }
+    if (ioreq->start + ioreq->size > blkdev->file_size) {
+        xen_pv_printf(xendev, 0, "error: access beyond end of file\n");
+        goto err;
+    }
+    return 0;
+
+err:
+    ioreq->status = BLKIF_RSP_ERROR;
+    return -1;
+}
+
+static int ioreq_grant_copy(struct ioreq *ioreq)
+{
+    struct XenBlkDev *blkdev = ioreq->blkdev;
+    struct XenLegacyDevice *xendev = &blkdev->xendev;
+    XenGrantCopySegment segs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+    int i, count, rc;
+    int64_t file_blk = blkdev->file_blk;
+    bool to_domain = (ioreq->req.operation == BLKIF_OP_READ);
+    void *virt = ioreq->buf;
+
+    if (ioreq->req.nr_segments == 0) {
+        return 0;
+    }
+
+    count = ioreq->req.nr_segments;
+
+    for (i = 0; i < count; i++) {
+        if (to_domain) {
+            segs[i].dest.foreign.ref = ioreq->req.seg[i].gref;
+            segs[i].dest.foreign.offset = ioreq->req.seg[i].first_sect *
+                file_blk;
+            segs[i].source.virt = virt;
+        } else {
+            segs[i].source.foreign.ref = ioreq->req.seg[i].gref;
+            segs[i].source.foreign.offset = ioreq->req.seg[i].first_sect *
+                file_blk;
+            segs[i].dest.virt = virt;
+        }
+        segs[i].len = (ioreq->req.seg[i].last_sect
+                       - ioreq->req.seg[i].first_sect + 1) * file_blk;
+        virt += segs[i].len;
+    }
+
+    rc = xen_be_copy_grant_refs(xendev, to_domain, segs, count);
+
+    if (rc) {
+        xen_pv_printf(xendev, 0,
+                      "failed to copy data %d\n", rc);
+        ioreq->aio_errors++;
+        return -1;
+    }
+
+    return rc;
+}
+
+static int ioreq_runio_qemu_aio(struct ioreq *ioreq);
+
+static void qemu_aio_complete(void *opaque, int ret)
+{
+    struct ioreq *ioreq = opaque;
+    struct XenBlkDev *blkdev = ioreq->blkdev;
+    struct XenLegacyDevice *xendev = &blkdev->xendev;
+
+    aio_context_acquire(blkdev->ctx);
+
+    if (ret != 0) {
+        xen_pv_printf(xendev, 0, "%s I/O error\n",
+                      ioreq->req.operation == BLKIF_OP_READ ? "read" : "write");
+        ioreq->aio_errors++;
+    }
+
+    ioreq->aio_inflight--;
+    if (ioreq->presync) {
+        ioreq->presync = 0;
+        ioreq_runio_qemu_aio(ioreq);
+        goto done;
+    }
+    if (ioreq->aio_inflight > 0) {
+        goto done;
+    }
+
+    switch (ioreq->req.operation) {
+    case BLKIF_OP_READ:
+        /* in case of failure ioreq->aio_errors is increased */
+        if (ret == 0) {
+            ioreq_grant_copy(ioreq);
+        }
+        qemu_vfree(ioreq->buf);
+        break;
+    case BLKIF_OP_WRITE:
+    case BLKIF_OP_FLUSH_DISKCACHE:
+        if (!ioreq->req.nr_segments) {
+            break;
+        }
+        qemu_vfree(ioreq->buf);
+        break;
+    default:
+        break;
+    }
+
+    ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY;
+    ioreq_finish(ioreq);
+
+    switch (ioreq->req.operation) {
+    case BLKIF_OP_WRITE:
+    case BLKIF_OP_FLUSH_DISKCACHE:
+        if (!ioreq->req.nr_segments) {
+            break;
+        }
+    case BLKIF_OP_READ:
+        if (ioreq->status == BLKIF_RSP_OKAY) {
+            block_acct_done(blk_get_stats(blkdev->blk), &ioreq->acct);
+        } else {
+            block_acct_failed(blk_get_stats(blkdev->blk), &ioreq->acct);
+        }
+        break;
+    case BLKIF_OP_DISCARD:
+    default:
+        break;
+    }
+    qemu_bh_schedule(blkdev->bh);
+
+done:
+    aio_context_release(blkdev->ctx);
+}
+
+static bool blk_split_discard(struct ioreq *ioreq, blkif_sector_t sector_number,
+                              uint64_t nr_sectors)
+{
+    struct XenBlkDev *blkdev = ioreq->blkdev;
+    int64_t byte_offset;
+    int byte_chunk;
+    uint64_t byte_remaining, limit;
+    uint64_t sec_start = sector_number;
+    uint64_t sec_count = nr_sectors;
+
+    /* Wrap around, or overflowing byte limit? */
+    if (sec_start + sec_count < sec_count ||
+        sec_start + sec_count > INT64_MAX >> BDRV_SECTOR_BITS) {
+        return false;
+    }
+
+    limit = BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS;
+    byte_offset = sec_start << BDRV_SECTOR_BITS;
+    byte_remaining = sec_count << BDRV_SECTOR_BITS;
+
+    do {
+        byte_chunk = byte_remaining > limit ? limit : byte_remaining;
+        ioreq->aio_inflight++;
+        blk_aio_pdiscard(blkdev->blk, byte_offset, byte_chunk,
+                         qemu_aio_complete, ioreq);
+        byte_remaining -= byte_chunk;
+        byte_offset += byte_chunk;
+    } while (byte_remaining > 0);
+
+    return true;
+}
+
+static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
+{
+    struct XenBlkDev *blkdev = ioreq->blkdev;
+
+    ioreq->buf = qemu_memalign(XC_PAGE_SIZE, ioreq->size);
+    if (ioreq->req.nr_segments &&
+        (ioreq->req.operation == BLKIF_OP_WRITE ||
+         ioreq->req.operation == BLKIF_OP_FLUSH_DISKCACHE) &&
+        ioreq_grant_copy(ioreq)) {
+        qemu_vfree(ioreq->buf);
+        goto err;
+    }
+
+    ioreq->aio_inflight++;
+    if (ioreq->presync) {
+        blk_aio_flush(ioreq->blkdev->blk, qemu_aio_complete, ioreq);
+        return 0;
+    }
+
+    switch (ioreq->req.operation) {
+    case BLKIF_OP_READ:
+        qemu_iovec_add(&ioreq->v, ioreq->buf, ioreq->size);
+        block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct,
+                         ioreq->v.size, BLOCK_ACCT_READ);
+        ioreq->aio_inflight++;
+        blk_aio_preadv(blkdev->blk, ioreq->start, &ioreq->v, 0,
+                       qemu_aio_complete, ioreq);
+        break;
+    case BLKIF_OP_WRITE:
+    case BLKIF_OP_FLUSH_DISKCACHE:
+        if (!ioreq->req.nr_segments) {
+            break;
+        }
+
+        qemu_iovec_add(&ioreq->v, ioreq->buf, ioreq->size);
+        block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct,
+                         ioreq->v.size,
+                         ioreq->req.operation == BLKIF_OP_WRITE ?
+                         BLOCK_ACCT_WRITE : BLOCK_ACCT_FLUSH);
+        ioreq->aio_inflight++;
+        blk_aio_pwritev(blkdev->blk, ioreq->start, &ioreq->v, 0,
+                        qemu_aio_complete, ioreq);
+        break;
+    case BLKIF_OP_DISCARD:
+    {
+        struct blkif_request_discard *req = (void *)&ioreq->req;
+        if (!blk_split_discard(ioreq, req->sector_number, req->nr_sectors)) {
+            goto err;
+        }
+        break;
+    }
+    default:
+        /* unknown operation (shouldn't happen -- parse catches this) */
+        goto err;
+    }
+
+    qemu_aio_complete(ioreq, 0);
+
+    return 0;
+
+err:
+    ioreq_finish(ioreq);
+    ioreq->status = BLKIF_RSP_ERROR;
+    return -1;
+}
+
+static int blk_send_response_one(struct ioreq *ioreq)
+{
+    struct XenBlkDev  *blkdev = ioreq->blkdev;
+    int               send_notify   = 0;
+    int               have_requests = 0;
+    blkif_response_t  *resp;
+
+    /* Place on the response ring for the relevant domain. */
+    switch (blkdev->protocol) {
+    case BLKIF_PROTOCOL_NATIVE:
+        resp = (blkif_response_t *)RING_GET_RESPONSE(
+            &blkdev->rings.native,
+            blkdev->rings.native.rsp_prod_pvt);
+        break;
+    case BLKIF_PROTOCOL_X86_32:
+        resp = (blkif_response_t *)RING_GET_RESPONSE(
+            &blkdev->rings.x86_32_part,
+            blkdev->rings.x86_32_part.rsp_prod_pvt);
+        break;
+    case BLKIF_PROTOCOL_X86_64:
+        resp = (blkif_response_t *)RING_GET_RESPONSE(
+            &blkdev->rings.x86_64_part,
+            blkdev->rings.x86_64_part.rsp_prod_pvt);
+        break;
+    default:
+        return 0;
+    }
+
+    resp->id        = ioreq->req.id;
+    resp->operation = ioreq->req.operation;
+    resp->status    = ioreq->status;
+
+    blkdev->rings.common.rsp_prod_pvt++;
+
+    RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blkdev->rings.common, send_notify);
+    if (blkdev->rings.common.rsp_prod_pvt == blkdev->rings.common.req_cons) {
+        /*
+         * Tail check for pending requests. Allows frontend to avoid
+         * notifications if requests are already in flight (lower
+         * overheads and promotes batching).
+         */
+        RING_FINAL_CHECK_FOR_REQUESTS(&blkdev->rings.common, have_requests);
+    } else if (RING_HAS_UNCONSUMED_REQUESTS(&blkdev->rings.common)) {
+        have_requests = 1;
+    }
+
+    if (have_requests) {
+        blkdev->more_work++;
+    }
+    return send_notify;
+}
+
+/* walk finished list, send outstanding responses, free requests */
+static void blk_send_response_all(struct XenBlkDev *blkdev)
+{
+    struct ioreq *ioreq;
+    int send_notify = 0;
+
+    while (!QLIST_EMPTY(&blkdev->finished)) {
+        ioreq = QLIST_FIRST(&blkdev->finished);
+        send_notify += blk_send_response_one(ioreq);
+        ioreq_release(ioreq, true);
+    }
+    if (send_notify) {
+        xen_pv_send_notify(&blkdev->xendev);
+    }
+}
+
+static int blk_get_request(struct XenBlkDev *blkdev, struct ioreq *ioreq,
+                           RING_IDX rc)
+{
+    switch (blkdev->protocol) {
+    case BLKIF_PROTOCOL_NATIVE:
+        memcpy(&ioreq->req, RING_GET_REQUEST(&blkdev->rings.native, rc),
+               sizeof(ioreq->req));
+        break;
+    case BLKIF_PROTOCOL_X86_32:
+        blkif_get_x86_32_req(&ioreq->req,
+                             RING_GET_REQUEST(&blkdev->rings.x86_32_part, rc));
+        break;
+    case BLKIF_PROTOCOL_X86_64:
+        blkif_get_x86_64_req(&ioreq->req,
+                             RING_GET_REQUEST(&blkdev->rings.x86_64_part, rc));
+        break;
+    }
+    /* Prevent the compiler from accessing the on-ring fields instead. */
+    barrier();
+    return 0;
+}
+
+static void blk_handle_requests(struct XenBlkDev *blkdev)
+{
+    RING_IDX rc, rp;
+    struct ioreq *ioreq;
+
+    blkdev->more_work = 0;
+
+    rc = blkdev->rings.common.req_cons;
+    rp = blkdev->rings.common.sring->req_prod;
+    xen_rmb(); /* Ensure we see queued requests up to 'rp'. */
+
+    blk_send_response_all(blkdev);
+    while (rc != rp) {
+        /* pull request from ring */
+        if (RING_REQUEST_CONS_OVERFLOW(&blkdev->rings.common, rc)) {
+            break;
+        }
+        ioreq = ioreq_start(blkdev);
+        if (ioreq == NULL) {
+            blkdev->more_work++;
+            break;
+        }
+        blk_get_request(blkdev, ioreq, rc);
+        blkdev->rings.common.req_cons = ++rc;
+
+        /* parse them */
+        if (ioreq_parse(ioreq) != 0) {
+
+            switch (ioreq->req.operation) {
+            case BLKIF_OP_READ:
+                block_acct_invalid(blk_get_stats(blkdev->blk),
+                                   BLOCK_ACCT_READ);
+                break;
+            case BLKIF_OP_WRITE:
+                block_acct_invalid(blk_get_stats(blkdev->blk),
+                                   BLOCK_ACCT_WRITE);
+                break;
+            case BLKIF_OP_FLUSH_DISKCACHE:
+                block_acct_invalid(blk_get_stats(blkdev->blk),
+                                   BLOCK_ACCT_FLUSH);
+            default:
+                break;
+            };
+
+            if (blk_send_response_one(ioreq)) {
+                xen_pv_send_notify(&blkdev->xendev);
+            }
+            ioreq_release(ioreq, false);
+            continue;
+        }
+
+        ioreq_runio_qemu_aio(ioreq);
+    }
+
+    if (blkdev->more_work && blkdev->requests_inflight < blkdev->max_requests) {
+        qemu_bh_schedule(blkdev->bh);
+    }
+}
+
+/* ------------------------------------------------------------- */
+
+static void blk_bh(void *opaque)
+{
+    struct XenBlkDev *blkdev = opaque;
+
+    aio_context_acquire(blkdev->ctx);
+    blk_handle_requests(blkdev);
+    aio_context_release(blkdev->ctx);
+}
+
+static void blk_alloc(struct XenLegacyDevice *xendev)
+{
+    struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+    Error *err = NULL;
+
+    trace_xen_disk_alloc(xendev->name);
+
+    QLIST_INIT(&blkdev->inflight);
+    QLIST_INIT(&blkdev->finished);
+    QLIST_INIT(&blkdev->freelist);
+
+    blkdev->iothread = iothread_create(xendev->name, &err);
+    assert(!err);
+
+    blkdev->ctx = iothread_get_aio_context(blkdev->iothread);
+    blkdev->bh = aio_bh_new(blkdev->ctx, blk_bh, blkdev);
+}
+
+static void blk_parse_discard(struct XenBlkDev *blkdev)
+{
+    struct XenLegacyDevice *xendev = &blkdev->xendev;
+    int enable;
+
+    blkdev->feature_discard = true;
+
+    if (xenstore_read_be_int(xendev, "discard-enable", &enable) == 0) {
+        blkdev->feature_discard = !!enable;
+    }
+
+    if (blkdev->feature_discard) {
+        xenstore_write_be_int(xendev, "feature-discard", 1);
+    }
+}
+
+static int blk_init(struct XenLegacyDevice *xendev)
+{
+    struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+    int info = 0;
+    char *directiosafe = NULL;
+
+    trace_xen_disk_init(xendev->name);
+
+    /* read xenstore entries */
+    if (blkdev->params == NULL) {
+        char *h = NULL;
+        blkdev->params = xenstore_read_be_str(xendev, "params");
+        if (blkdev->params != NULL) {
+            h = strchr(blkdev->params, ':');
+        }
+        if (h != NULL) {
+            blkdev->fileproto = blkdev->params;
+            blkdev->filename  = h + 1;
+            *h = 0;
+        } else {
+            blkdev->fileproto = "<unset>";
+            blkdev->filename  = blkdev->params;
+        }
+    }
+    if (!strcmp("aio", blkdev->fileproto)) {
+        blkdev->fileproto = "raw";
+    }
+    if (!strcmp("vhd", blkdev->fileproto)) {
+        blkdev->fileproto = "vpc";
+    }
+    if (blkdev->mode == NULL) {
+        blkdev->mode = xenstore_read_be_str(xendev, "mode");
+    }
+    if (blkdev->type == NULL) {
+        blkdev->type = xenstore_read_be_str(xendev, "type");
+    }
+    if (blkdev->dev == NULL) {
+        blkdev->dev = xenstore_read_be_str(xendev, "dev");
+    }
+    if (blkdev->devtype == NULL) {
+        blkdev->devtype = xenstore_read_be_str(xendev, "device-type");
+    }
+    directiosafe = xenstore_read_be_str(xendev, "direct-io-safe");
+    blkdev->directiosafe = (directiosafe && atoi(directiosafe));
+
+    /* do we have all we need? */
+    if (blkdev->params == NULL ||
+        blkdev->mode == NULL   ||
+        blkdev->type == NULL   ||
+        blkdev->dev == NULL) {
+        goto out_error;
+    }
+
+    /* read-only ? */
+    if (strcmp(blkdev->mode, "w")) {
+        info  |= VDISK_READONLY;
+    }
+
+    /* cdrom ? */
+    if (blkdev->devtype && !strcmp(blkdev->devtype, "cdrom")) {
+        info  |= VDISK_CDROM;
+    }
+
+    blkdev->file_blk  = BLOCK_SIZE;
+
+    /* fill info
+     * blk_connect supplies sector-size and sectors
+     */
+    xenstore_write_be_int(xendev, "feature-flush-cache", 1);
+    xenstore_write_be_int(xendev, "info", info);
+
+    xenstore_write_be_int(xendev, "max-ring-page-order",
+                          MAX_RING_PAGE_ORDER);
+
+    blk_parse_discard(blkdev);
+
+    g_free(directiosafe);
+    return 0;
+
+out_error:
+    g_free(blkdev->params);
+    blkdev->params = NULL;
+    g_free(blkdev->mode);
+    blkdev->mode = NULL;
+    g_free(blkdev->type);
+    blkdev->type = NULL;
+    g_free(blkdev->dev);
+    blkdev->dev = NULL;
+    g_free(blkdev->devtype);
+    blkdev->devtype = NULL;
+    g_free(directiosafe);
+    blkdev->directiosafe = false;
+    return -1;
+}
+
+static int blk_connect(struct XenLegacyDevice *xendev)
+{
+    struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+    int index, qflags;
+    bool readonly = true;
+    bool writethrough = true;
+    int order, ring_ref;
+    unsigned int ring_size, max_grants;
+    unsigned int i;
+
+    trace_xen_disk_connect(xendev->name);
+
+    /* read-only ? */
+    if (blkdev->directiosafe) {
+        qflags = BDRV_O_NOCACHE | BDRV_O_NATIVE_AIO;
+    } else {
+        qflags = 0;
+        writethrough = false;
+    }
+    if (strcmp(blkdev->mode, "w") == 0) {
+        qflags |= BDRV_O_RDWR;
+        readonly = false;
+    }
+    if (blkdev->feature_discard) {
+        qflags |= BDRV_O_UNMAP;
+    }
+
+    /* init qemu block driver */
+    index = (xendev->dev - 202 * 256) / 16;
+    blkdev->dinfo = drive_get(IF_XEN, 0, index);
+    if (!blkdev->dinfo) {
+        Error *local_err = NULL;
+        QDict *options = NULL;
+
+        if (strcmp(blkdev->fileproto, "<unset>")) {
+            options = qdict_new();
+            qdict_put_str(options, "driver", blkdev->fileproto);
+        }
+
+        /* setup via xenbus -> create new block driver instance */
+        xen_pv_printf(xendev, 2, "create new bdrv (xenbus setup)\n");
+        blkdev->blk = blk_new_open(blkdev->filename, NULL, options,
+                                   qflags, &local_err);
+        if (!blkdev->blk) {
+            xen_pv_printf(xendev, 0, "error: %s\n",
+                          error_get_pretty(local_err));
+            error_free(local_err);
+            return -1;
+        }
+        blk_set_enable_write_cache(blkdev->blk, !writethrough);
+    } else {
+        /* setup via qemu cmdline -> already setup for us */
+        xen_pv_printf(xendev, 2,
+                      "get configured bdrv (cmdline setup)\n");
+        blkdev->blk = blk_by_legacy_dinfo(blkdev->dinfo);
+        if (blk_is_read_only(blkdev->blk) && !readonly) {
+            xen_pv_printf(xendev, 0, "Unexpected read-only drive");
+            blkdev->blk = NULL;
+            return -1;
+        }
+        /* blkdev->blk is not create by us, we get a reference
+         * so we can blk_unref() unconditionally */
+        blk_ref(blkdev->blk);
+    }
+    blk_attach_dev_legacy(blkdev->blk, blkdev);
+    blkdev->file_size = blk_getlength(blkdev->blk);
+    if (blkdev->file_size < 0) {
+        BlockDriverState *bs = blk_bs(blkdev->blk);
+        const char *drv_name = bs ? bdrv_get_format_name(bs) : NULL;
+        xen_pv_printf(xendev, 1, "blk_getlength: %d (%s) | drv %s\n",
+                      (int)blkdev->file_size, strerror(-blkdev->file_size),
+                      drv_name ?: "-");
+        blkdev->file_size = 0;
+    }
+
+    xen_pv_printf(xendev, 1, "type \"%s\", fileproto \"%s\", filename \"%s\","
+                  " size %" PRId64 " (%" PRId64 " MB)\n",
+                  blkdev->type, blkdev->fileproto, blkdev->filename,
+                  blkdev->file_size, blkdev->file_size / MiB);
+
+    /* Fill in number of sector size and number of sectors */
+    xenstore_write_be_int(xendev, "sector-size", blkdev->file_blk);
+    xenstore_write_be_int64(xendev, "sectors",
+                            blkdev->file_size / blkdev->file_blk);
+
+    if (xenstore_read_fe_int(xendev, "ring-page-order",
+                             &order) == -1) {
+        blkdev->nr_ring_ref = 1;
+
+        if (xenstore_read_fe_int(xendev, "ring-ref",
+                                 &ring_ref) == -1) {
+            return -1;
+        }
+        blkdev->ring_ref[0] = ring_ref;
+
+    } else if (order >= 0 && order <= MAX_RING_PAGE_ORDER) {
+        blkdev->nr_ring_ref = 1 << order;
+
+        for (i = 0; i < blkdev->nr_ring_ref; i++) {
+            char *key;
+
+            key = g_strdup_printf("ring-ref%u", i);
+            if (!key) {
+                return -1;
+            }
+
+            if (xenstore_read_fe_int(xendev, key,
+                                     &ring_ref) == -1) {
+                g_free(key);
+                return -1;
+            }
+            blkdev->ring_ref[i] = ring_ref;
+
+            g_free(key);
+        }
+    } else {
+        xen_pv_printf(xendev, 0, "invalid ring-page-order: %d\n",
+                      order);
+        return -1;
+    }
+
+    if (xenstore_read_fe_int(xendev, "event-channel",
+                             &xendev->remote_port) == -1) {
+        return -1;
+    }
+
+    if (!xendev->protocol) {
+        blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
+    } else if (strcmp(xendev->protocol, XEN_IO_PROTO_ABI_NATIVE) == 0) {
+        blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
+    } else if (strcmp(xendev->protocol, XEN_IO_PROTO_ABI_X86_32) == 0) {
+        blkdev->protocol = BLKIF_PROTOCOL_X86_32;
+    } else if (strcmp(xendev->protocol, XEN_IO_PROTO_ABI_X86_64) == 0) {
+        blkdev->protocol = BLKIF_PROTOCOL_X86_64;
+    } else {
+        blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
+    }
+
+    ring_size = XC_PAGE_SIZE * blkdev->nr_ring_ref;
+    switch (blkdev->protocol) {
+    case BLKIF_PROTOCOL_NATIVE:
+    {
+        blkdev->max_requests = __CONST_RING_SIZE(blkif, ring_size);
+        break;
+    }
+    case BLKIF_PROTOCOL_X86_32:
+    {
+        blkdev->max_requests = __CONST_RING_SIZE(blkif_x86_32, ring_size);
+        break;
+    }
+    case BLKIF_PROTOCOL_X86_64:
+    {
+        blkdev->max_requests = __CONST_RING_SIZE(blkif_x86_64, ring_size);
+        break;
+    }
+    default:
+        return -1;
+    }
+
+    /* Add on the number needed for the ring pages */
+    max_grants = blkdev->nr_ring_ref;
+
+    xen_be_set_max_grant_refs(xendev, max_grants);
+    blkdev->sring = xen_be_map_grant_refs(xendev, blkdev->ring_ref,
+                                          blkdev->nr_ring_ref,
+                                          PROT_READ | PROT_WRITE);
+    if (!blkdev->sring) {
+        return -1;
+    }
+
+    switch (blkdev->protocol) {
+    case BLKIF_PROTOCOL_NATIVE:
+    {
+        blkif_sring_t *sring_native = blkdev->sring;
+        BACK_RING_INIT(&blkdev->rings.native, sring_native, ring_size);
+        break;
+    }
+    case BLKIF_PROTOCOL_X86_32:
+    {
+        blkif_x86_32_sring_t *sring_x86_32 = blkdev->sring;
+
+        BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, ring_size);
+        break;
+    }
+    case BLKIF_PROTOCOL_X86_64:
+    {
+        blkif_x86_64_sring_t *sring_x86_64 = blkdev->sring;
+
+        BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, ring_size);
+        break;
+    }
+    }
+
+    blk_set_aio_context(blkdev->blk, blkdev->ctx);
+
+    xen_be_bind_evtchn(xendev);
+
+    xen_pv_printf(xendev, 1, "ok: proto %s, nr-ring-ref %u, "
+                  "remote port %d, local port %d\n",
+                  xendev->protocol, blkdev->nr_ring_ref,
+                  xendev->remote_port, xendev->local_port);
+    return 0;
+}
+
+static void blk_disconnect(struct XenLegacyDevice *xendev)
+{
+    struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+
+    trace_xen_disk_disconnect(xendev->name);
+
+    aio_context_acquire(blkdev->ctx);
+
+    if (blkdev->blk) {
+        blk_set_aio_context(blkdev->blk, qemu_get_aio_context());
+        blk_detach_dev(blkdev->blk, blkdev);
+        blk_unref(blkdev->blk);
+        blkdev->blk = NULL;
+    }
+    xen_pv_unbind_evtchn(xendev);
+
+    aio_context_release(blkdev->ctx);
+
+    if (blkdev->sring) {
+        xen_be_unmap_grant_refs(xendev, blkdev->sring,
+                                blkdev->nr_ring_ref);
+        blkdev->sring = NULL;
+    }
+}
+
+static int blk_free(struct XenLegacyDevice *xendev)
+{
+    struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+    struct ioreq *ioreq;
+
+    trace_xen_disk_free(xendev->name);
+
+    blk_disconnect(xendev);
+
+    while (!QLIST_EMPTY(&blkdev->freelist)) {
+        ioreq = QLIST_FIRST(&blkdev->freelist);
+        QLIST_REMOVE(ioreq, list);
+        qemu_iovec_destroy(&ioreq->v);
+        g_free(ioreq);
+    }
+
+    g_free(blkdev->params);
+    g_free(blkdev->mode);
+    g_free(blkdev->type);
+    g_free(blkdev->dev);
+    g_free(blkdev->devtype);
+    qemu_bh_delete(blkdev->bh);
+    iothread_destroy(blkdev->iothread);
+    return 0;
+}
+
+static void blk_event(struct XenLegacyDevice *xendev)
+{
+    struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+
+    qemu_bh_schedule(blkdev->bh);
+}
+
+struct XenDevOps xen_blkdev_ops = {
+    .flags      = DEVOPS_FLAG_NEED_GNTDEV,
+    .size       = sizeof(struct XenBlkDev),
+    .alloc      = blk_alloc,
+    .init       = blk_init,
+    .initialise = blk_connect,
+    .disconnect = blk_disconnect,
+    .event      = blk_event,
+    .free       = blk_free,
+};