Re: [Qemu-devel] [PATCH v2 2/4] vhost-user-blk: introduce a new vhost-user-blk host device

[Liu, Changpeng]

> -----Original Message-----
> From: Marc-André Lureau [mailto:address@hidden
> Sent: Wednesday, August 9, 2017 11:39 PM
> To: Liu, Changpeng <address@hidden>
> Cc: address@hidden; address@hidden; address@hidden;
> address@hidden; address@hidden; Harris, James R
> <address@hidden>
> Subject: Re: [PATCH v2 2/4] vhost-user-blk: introduce a new vhost-user-blk 
> host
> device
> 
> Hi
> 
> ----- Original Message -----
> > This commit introduces a new vhost-user device for block, it uses a
> > chardev to connect with the backend, same with Qemu virito-blk device,
> > Guest OS still uses the virtio-blk frontend driver.
> >
> > To use it, start Qemu with command line like this:
> >
> > qemu-system-x86_64 \
> >     -chardev socket,id=char0,path=/path/vhost.socket \
> >     -device vhost-user-blk-pci,chardev=char0,num_queues=...
> >
> > Different with exist Qemu virtio-blk host device, it makes more easy
> > for users to implement their own I/O processing logic, such as all
> > user space I/O stack against hardware block device. It uses the new
> > vhost messages(VHOST_USER_GET_CONFIG) to get block virtio config
> > information from backend process.
> >
> > Signed-off-by: Changpeng Liu <address@hidden>
> > ---
> >  configure                          |  11 ++
> >  hw/block/Makefile.objs             |   3 +
> >  hw/block/vhost-user-blk.c          | 360
> >  +++++++++++++++++++++++++++++++++++++
> >  hw/virtio/virtio-pci.c             |  55 ++++++
> >  hw/virtio/virtio-pci.h             |  18 ++
> >  include/hw/virtio/vhost-user-blk.h |  40 +++++
> >  6 files changed, 487 insertions(+)
> >  create mode 100644 hw/block/vhost-user-blk.c
> >  create mode 100644 include/hw/virtio/vhost-user-blk.h
> >
> > diff --git a/configure b/configure
> > index dd73cce..1452c66 100755
> > --- a/configure
> > +++ b/configure
> > @@ -305,6 +305,7 @@ tcg="yes"
> >
> >  vhost_net="no"
> >  vhost_scsi="no"
> > +vhost_user_blk="no"
> >  vhost_vsock="no"
> >  vhost_user=""
> >  kvm="no"
> > @@ -779,6 +780,7 @@ Linux)
> >    kvm="yes"
> >    vhost_net="yes"
> >    vhost_scsi="yes"
> > +  vhost_user_blk="yes"
> >    vhost_vsock="yes"
> >    QEMU_INCLUDES="-I\$(SRC_PATH)/linux-headers -I$(pwd)/linux-headers
> >    $QEMU_INCLUDES"
> >    supported_os="yes"
> > @@ -1136,6 +1138,10 @@ for opt do
> >    ;;
> >    --enable-vhost-scsi) vhost_scsi="yes"
> >    ;;
> > +  --disable-vhost-user-blk) vhost_user_blk="no"
> > +  ;;
> > +  --enable-vhost-user-blk) vhost_user_blk="yes"
> > +  ;;
> 
> I suggest we don't add yet another configure option, but reuse the recently
> introduced --enable-vhost-user (that should cover all vhost-user devices for 
> now,
> but may learn to enable specific devices if needed in the future).
Yes, I noticed there is a new vhost-user configuration, sounds good to me if 
other devices
such as vhost-net and vhost-scsi also use the same configuration option.
> 
> >    --disable-vhost-vsock) vhost_vsock="no"
> >    ;;
> >    --enable-vhost-vsock) vhost_vsock="yes"
> > @@ -1506,6 +1512,7 @@ disabled with --disable-FEATURE, default is enabled if
> > available:
> >    cap-ng          libcap-ng support
> >    attr            attr and xattr support
> >    vhost-net       vhost-net acceleration support
> > +  vhost-user-blk  VM virtio-blk acceleration in user space
> >    spice           spice
> >    rbd             rados block device (rbd)
> >    libiscsi        iscsi support
> > @@ -5365,6 +5372,7 @@ echo "posix_madvise     $posix_madvise"
> >  echo "libcap-ng support $cap_ng"
> >  echo "vhost-net support $vhost_net"
> >  echo "vhost-scsi support $vhost_scsi"
> > +echo "vhost-user-blk support $vhost_user_blk"
> >  echo "vhost-vsock support $vhost_vsock"
> >  echo "vhost-user support $vhost_user"
> >  echo "Trace backends    $trace_backends"
> > @@ -5776,6 +5784,9 @@ fi
> >  if test "$vhost_scsi" = "yes" ; then
> >    echo "CONFIG_VHOST_SCSI=y" >> $config_host_mak
> >  fi
> > +if test "$vhost_user_blk" = "yes" ; then
> > +  echo "CONFIG_VHOST_USER_BLK=y" >> $config_host_mak
> > +fi
> >  if test "$vhost_net" = "yes" -a "$vhost_user" = "yes"; then
> >    echo "CONFIG_VHOST_NET_USED=y" >> $config_host_mak
> >  fi
> > diff --git a/hw/block/Makefile.objs b/hw/block/Makefile.objs
> > index e0ed980..4c19a58 100644
> > --- a/hw/block/Makefile.objs
> > +++ b/hw/block/Makefile.objs
> > @@ -13,3 +13,6 @@ obj-$(CONFIG_SH4) += tc58128.o
> >
> >  obj-$(CONFIG_VIRTIO) += virtio-blk.o
> >  obj-$(CONFIG_VIRTIO) += dataplane/
> > +ifeq ($(CONFIG_VIRTIO),y)
> > +obj-$(CONFIG_VHOST_USER_BLK) += vhost-user-blk.o
> > +endif
> > diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
> > new file mode 100644
> > index 0000000..8aa9fa9
> > --- /dev/null
> > +++ b/hw/block/vhost-user-blk.c
> > @@ -0,0 +1,360 @@
> > +/*
> > + * vhost-user-blk host device
> > + *
> > + * Copyright IBM, Corp. 2011
> > + * Copyright(C) 2017 Intel Corporation.
> > + *
> > + * Authors:
> > + *  Stefan Hajnoczi <address@hidden>
> > + *  Changpeng Liu <address@hidden>
> > + *
> > + * This work is licensed under the terms of the GNU LGPL, version 2 or
> > later.
> > + * See the COPYING.LIB file in the top-level directory.
> > + *
> > + */
> > +
> > +#include "qemu/osdep.h"
> > +#include "qapi/error.h"
> > +#include "qemu/error-report.h"
> > +#include "qemu/typedefs.h"
> > +#include "qemu/cutils.h"
> > +#include "qom/object.h"
> > +#include "hw/qdev-core.h"
> > +#include "hw/virtio/vhost.h"
> > +#include "hw/virtio/vhost-user-blk.h"
> > +#include "hw/virtio/virtio.h"
> > +#include "hw/virtio/virtio-bus.h"
> > +#include "hw/virtio/virtio-access.h"
> > +
> > +static const int user_feature_bits[] = {
> > +    VIRTIO_BLK_F_SIZE_MAX,
> > +    VIRTIO_BLK_F_SEG_MAX,
> > +    VIRTIO_BLK_F_GEOMETRY,
> > +    VIRTIO_BLK_F_BLK_SIZE,
> > +    VIRTIO_BLK_F_TOPOLOGY,
> > +    VIRTIO_BLK_F_SCSI,
> > +    VIRTIO_BLK_F_MQ,
> > +    VIRTIO_BLK_F_RO,
> > +    VIRTIO_BLK_F_FLUSH,
> > +    VIRTIO_BLK_F_BARRIER,
> > +    VIRTIO_BLK_F_WCE,
> > +    VIRTIO_F_VERSION_1,
> > +    VIRTIO_RING_F_INDIRECT_DESC,
> > +    VIRTIO_RING_F_EVENT_IDX,
> > +    VIRTIO_F_NOTIFY_ON_EMPTY,
> > +    VHOST_INVALID_FEATURE_BIT
> > +};
> > +
> > +static void vhost_user_blk_update_config(VirtIODevice *vdev, uint8_t
> > *config)
> > +{
> > +    VHostUserBlk *s = VHOST_USER_BLK(vdev);
> > +
> > +    memcpy(config, &s->blkcfg, sizeof(struct virtio_blk_config));
> > +}
> > +
> > +static void vhost_user_blk_set_config(VirtIODevice *vdev, const uint8_t
> > *config)
> > +{
> > +    VHostUserBlk *s = VHOST_USER_BLK(vdev);
> > +    struct virtio_blk_config *blkcfg = (struct virtio_blk_config *)config;
> > +    int ret;
> > +
> > +    if (blkcfg->wce == s->blkcfg.wce) {
> > +        return;
> 
> Is write-cache the only config change the slave is interested in?
> 
> > +    }
> > +
> > +    ret = vhost_dev_set_config(&s->dev, config,
> > +                              sizeof(struct virtio_blk_config));
> > +    if (ret) {
> > +        error_report("set device config space failed");
> > +        return;
> > +    }
> > +
> > +    s->blkcfg.wce = blkcfg->wce;
> > +}
> > +
> > +static void vhost_user_blk_handle_config_change(struct vhost_dev *dev)
> > +{
> > +    int ret;
> > +    struct virtio_blk_config blkcfg;
> > +    VHostUserBlk *s = VHOST_USER_BLK(dev->vdev);
> > +
> > +    ret = vhost_dev_get_config(dev, (uint8_t *)&blkcfg,
> > +                               sizeof(struct virtio_blk_config));
> > +    if (ret < 0) {
> > +        error_report("get config space failed");
> > +        return;
> > +    }
> > +
> > +    memcpy(&s->blkcfg, &blkcfg, sizeof(struct virtio_blk_config));
> > +    memcpy(dev->vdev->config, &blkcfg, sizeof(struct virtio_blk_config));
> 
> Why do you need to have s->blkcfg if you can use dev->vdev->config ?
Save a copy to local to avoid frequently get config from slave via socket 
message.
> 
> > +    virtio_notify_config(dev->vdev);
> > +}
> > +
> > +const VhostDevConfigOps blk_ops = {
> > +    .vhost_dev_config_notifier = vhost_user_blk_handle_config_change,
> > +};
> > +
> > +static void vhost_user_blk_start(VirtIODevice *vdev)
> > +{
> > +    VHostUserBlk *s = VHOST_USER_BLK(vdev);
> > +    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> > +    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> > +    int i, ret;
> > +
> > +    if (!k->set_guest_notifiers) {
> > +        error_report("binding does not support guest notifiers");
> > +        return;
> > +    }
> > +
> > +    ret = vhost_dev_enable_notifiers(&s->dev, vdev);
> > +    if (ret < 0) {
> > +        error_report("Error enabling host notifiers: %d", -ret);
> > +        return;
> > +    }
> > +
> > +    ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, true);
> > +    if (ret < 0) {
> > +        error_report("Error binding guest notifier: %d", -ret);
> > +        goto err_host_notifiers;
> > +    }
> > +
> > +    s->dev.acked_features = vdev->guest_features;
> > +    ret = vhost_dev_start(&s->dev, vdev);
> > +    if (ret < 0) {
> > +        error_report("Error starting vhost: %d", -ret);
> > +        goto err_guest_notifiers;
> > +    }
> > +
> > +    /* guest_notifier_mask/pending not used yet, so just unmask
> > +     * everything here. virtio-pci will do the right thing by
> > +     * enabling/disabling irqfd.
> > +     */
> > +    for (i = 0; i < s->dev.nvqs; i++) {
> > +        vhost_virtqueue_mask(&s->dev, vdev, i, false);
> > +    }
> > +
> > +    return;
> > +
> > +err_guest_notifiers:
> > +    k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
> > +err_host_notifiers:
> > +    vhost_dev_disable_notifiers(&s->dev, vdev);
> > +}
> > +
> > +static void vhost_user_blk_stop(VirtIODevice *vdev)
> > +{
> > +    VHostUserBlk *s = VHOST_USER_BLK(vdev);
> > +    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> > +    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> > +    int ret;
> > +
> > +    if (!k->set_guest_notifiers) {
> > +        return;
> > +    }
> > +
> > +    vhost_dev_stop(&s->dev, vdev);
> > +
> > +    ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
> > +    if (ret < 0) {
> > +        error_report("vhost guest notifier cleanup failed: %d", ret);
> > +        return;
> > +    }
> > +
> > +    vhost_dev_disable_notifiers(&s->dev, vdev);
> > +}
> > +
> > +static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
> > +{
> > +    VHostUserBlk *s = VHOST_USER_BLK(vdev);
> > +    bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
> > +
> > +    if (!vdev->vm_running) {
> > +        should_start = false;
> > +    }
> > +
> > +    if (s->dev.started == should_start) {
> > +        return;
> > +    }
> > +
> > +    if (should_start) {
> > +        vhost_user_blk_start(vdev);
> > +    } else {
> > +        vhost_user_blk_stop(vdev);
> > +    }
> > +
> > +}
> > +
> > +static uint64_t vhost_user_blk_get_features(VirtIODevice *vdev,
> > +                                            uint64_t features,
> > +                                            Error **errp)
> > +{
> > +    VHostUserBlk *s = VHOST_USER_BLK(vdev);
> > +    uint64_t get_features;
> > +
> > +    /* Turn on pre-defined features */
> > +    features |= s->host_features;
> > +
> > +    get_features = vhost_get_features(&s->dev, user_feature_bits, 
> > features);
> > +
> > +    return get_features;
> > +}
> > +
> > +static void vhost_user_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
> > +{
> > +
> > +}
> > +
> > +static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
> > +{
> > +    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> > +    VHostUserBlk *s = VHOST_USER_BLK(vdev);
> > +    int i, ret;
> > +
> > +    if (!s->chardev.chr) {
> > +        error_setg(errp, "vhost-user-blk: chardev is mandatory");
> > +        return;
> > +    }
> > +
> > +    if (!s->num_queues || s->num_queues > VIRTIO_QUEUE_MAX) {
> > +        error_setg(errp, "vhost-user-blk: invalid number of IO queues");
> > +        return;
> > +    }
> > +
> > +    if (!s->queue_size) {
> > +        error_setg(errp, "vhost-user-blk: queue size must be non-zero");
> > +        return;
> > +    }
> > +
> > +    virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK,
> > +                sizeof(struct virtio_blk_config));
> > +
> > +    for (i = 0; i < s->num_queues; i++) {
> > +        virtio_add_queue(vdev, s->queue_size,
> > +                         vhost_user_blk_handle_output);
> > +    }
> > +
> > +    s->dev.nvqs = s->num_queues;
> > +    s->dev.vqs = g_new(struct vhost_virtqueue, s->dev.nvqs);
> > +    s->dev.vq_index = 0;
> > +    s->dev.backend_features = 0;
> > +
> > +    ret = vhost_dev_init(&s->dev, &s->chardev, VHOST_BACKEND_TYPE_USER,
> 0);
> > +    if (ret < 0) {
> > +        error_setg(errp, "vhost-user-blk: vhost initialization failed: %s",
> > +                   strerror(-ret));
> > +        goto virtio_err;
> > +    }
> > +
> > +    ret = vhost_dev_get_config(&s->dev, (uint8_t *)&s->blkcfg,
> > +                              sizeof(struct virtio_blk_config));
> > +    if (ret < 0) {
> > +        error_setg(errp, "vhost-user-blk: get block config failed");
> > +        goto vhost_err;
> > +    }
> > +
> > +    if (s->blkcfg.num_queues != s->num_queues) {
> > +        s->blkcfg.num_queues = s->num_queues;
> > +    }
> > +
> > +    vhost_dev_set_config_notifier(&s->dev, &blk_ops);
> > +
> > +    return;
> > +
> > +vhost_err:
> > +    vhost_dev_cleanup(&s->dev);
> > +virtio_err:
> > +    g_free(s->dev.vqs);
> > +    virtio_cleanup(vdev);
> > +}
> > +
> > +static void vhost_user_blk_device_unrealize(DeviceState *dev, Error **errp)
> > +{
> > +    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> > +    VHostUserBlk *s = VHOST_USER_BLK(dev);
> > +
> > +    vhost_user_blk_set_status(vdev, 0);
> > +    vhost_dev_cleanup(&s->dev);
> > +    g_free(s->dev.vqs);
> > +    virtio_cleanup(vdev);
> > +}
> > +
> > +static void vhost_user_blk_instance_init(Object *obj)
> > +{
> > +    VHostUserBlk *s = VHOST_USER_BLK(obj);
> > +
> > +    device_add_bootindex_property(obj, &s->bootindex, "bootindex",
> > +                                  "/address@hidden,0", DEVICE(obj), NULL);
> > +}
> > +
> > +static const VMStateDescription vmstate_vhost_user_blk = {
> > +    .name = "vhost-user-blk",
> > +    .minimum_version_id = 1,
> > +    .version_id = 1,
> > +    .fields = (VMStateField[]) {
> > +        VMSTATE_VIRTIO_DEVICE,
> > +        VMSTATE_END_OF_LIST()
> > +    },
> > +};
> > +
> > +static Property vhost_user_blk_properties[] = {
> > +    DEFINE_PROP_CHR("chardev", VHostUserBlk, chardev),
> > +    DEFINE_PROP_UINT16("num_queues", VHostUserBlk, num_queues, 1),
> > +    DEFINE_PROP_UINT32("queue_size", VHostUserBlk, queue_size, 128),
> > +    DEFINE_PROP_BIT64("f_size_max", VHostUserBlk, host_features,
> > +                      VIRTIO_BLK_F_SIZE_MAX, true),
> > +    DEFINE_PROP_BIT64("f_sizemax", VHostUserBlk, host_features,
> > +                      VIRTIO_BLK_F_SIZE_MAX, true),
> > +    DEFINE_PROP_BIT64("f_segmax", VHostUserBlk, host_features,
> > +                      VIRTIO_BLK_F_SEG_MAX, true),
> > +    DEFINE_PROP_BIT64("f_geometry", VHostUserBlk, host_features,
> > +                      VIRTIO_BLK_F_GEOMETRY, true),
> > +    DEFINE_PROP_BIT64("f_readonly", VHostUserBlk, host_features,
> > +                      VIRTIO_BLK_F_RO, false),
> > +    DEFINE_PROP_BIT64("f_blocksize", VHostUserBlk, host_features,
> > +                      VIRTIO_BLK_F_BLK_SIZE, true),
> > +    DEFINE_PROP_BIT64("f_topology", VHostUserBlk, host_features,
> > +                      VIRTIO_BLK_F_TOPOLOGY, true),
> > +    DEFINE_PROP_BIT64("f_multiqueue", VHostUserBlk, host_features,
> > +                      VIRTIO_BLK_F_MQ, true),
> > +    DEFINE_PROP_BIT64("f_flush", VHostUserBlk, host_features,
> > +                      VIRTIO_BLK_F_FLUSH, true),
> > +    DEFINE_PROP_BIT64("f_barrier", VHostUserBlk, host_features,
> > +                      VIRTIO_BLK_F_BARRIER, false),
> > +    DEFINE_PROP_BIT64("f_scsi", VHostUserBlk, host_features,
> > +                      VIRTIO_BLK_F_SCSI, false),
> > +    DEFINE_PROP_BIT64("f_wce", VHostUserBlk, host_features,
> > +                      VIRTIO_BLK_F_WCE, false),
> > +    DEFINE_PROP_END_OF_LIST(),
> > +};
> > +
> > +static void vhost_user_blk_class_init(ObjectClass *klass, void *data)
> > +{
> > +    DeviceClass *dc = DEVICE_CLASS(klass);
> > +    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
> > +
> > +    dc->props = vhost_user_blk_properties;
> > +    dc->vmsd = &vmstate_vhost_user_blk;
> > +    set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
> > +    vdc->realize = vhost_user_blk_device_realize;
> > +    vdc->unrealize = vhost_user_blk_device_unrealize;
> > +    vdc->get_config = vhost_user_blk_update_config;
> > +    vdc->set_config = vhost_user_blk_set_config;
> > +    vdc->get_features = vhost_user_blk_get_features;
> > +    vdc->set_status = vhost_user_blk_set_status;
> > +}
> > +
> > +static const TypeInfo vhost_user_blk_info = {
> > +    .name = TYPE_VHOST_USER_BLK,
> > +    .parent = TYPE_VIRTIO_DEVICE,
> > +    .instance_size = sizeof(VHostUserBlk),
> > +    .instance_init = vhost_user_blk_instance_init,
> > +    .class_init = vhost_user_blk_class_init,
> > +};
> > +
> > +static void virtio_register_types(void)
> > +{
> > +    type_register_static(&vhost_user_blk_info);
> > +}
> > +
> > +type_init(virtio_register_types)
> > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > index 8b0d6b6..be9a992 100644
> > --- a/hw/virtio/virtio-pci.c
> > +++ b/hw/virtio/virtio-pci.c
> > @@ -2012,6 +2012,58 @@ static const TypeInfo virtio_blk_pci_info = {
> >      .class_init    = virtio_blk_pci_class_init,
> >  };
> >
> > +#ifdef CONFIG_VHOST_USER_BLK
> > +/* vhost-user-blk */
> > +
> > +static Property vhost_user_blk_pci_properties[] = {
> > +    DEFINE_PROP_UINT32("class", VirtIOPCIProxy, class_code, 0),
> > +    DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
> > +    DEFINE_PROP_END_OF_LIST(),
> > +};
> > +
> > +static void vhost_user_blk_pci_realize(VirtIOPCIProxy *vpci_dev, Error
> > **errp)
> > +{
> > +    VHostUserBlkPCI *dev = VHOST_USER_BLK_PCI(vpci_dev);
> > +    DeviceState *vdev = DEVICE(&dev->vdev);
> > +
> > +    qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
> > +    object_property_set_bool(OBJECT(vdev), true, "realized", errp);
> > +}
> > +
> > +static void vhost_user_blk_pci_class_init(ObjectClass *klass, void *data)
> > +{
> > +    DeviceClass *dc = DEVICE_CLASS(klass);
> > +    VirtioPCIClass *k = VIRTIO_PCI_CLASS(klass);
> > +    PCIDeviceClass *pcidev_k = PCI_DEVICE_CLASS(klass);
> > +
> > +    set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
> > +    dc->props = vhost_user_blk_pci_properties;
> > +    k->realize = vhost_user_blk_pci_realize;
> > +    pcidev_k->vendor_id = PCI_VENDOR_ID_REDHAT_QUMRANET;
> > +    pcidev_k->device_id = PCI_DEVICE_ID_VIRTIO_BLOCK;
> > +    pcidev_k->revision = VIRTIO_PCI_ABI_VERSION;
> > +    pcidev_k->class_id = PCI_CLASS_STORAGE_SCSI;
> > +}
> > +
> > +static void vhost_user_blk_pci_instance_init(Object *obj)
> > +{
> > +    VHostUserBlkPCI *dev = VHOST_USER_BLK_PCI(obj);
> > +
> > +    virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
> > +                                TYPE_VHOST_USER_BLK);
> > +    object_property_add_alias(obj, "bootindex", OBJECT(&dev->vdev),
> > +                              "bootindex", &error_abort);
> > +}
> > +
> > +static const TypeInfo vhost_user_blk_pci_info = {
> > +    .name           = TYPE_VHOST_USER_BLK_PCI,
> > +    .parent         = TYPE_VIRTIO_PCI,
> > +    .instance_size  = sizeof(VHostUserBlkPCI),
> > +    .instance_init  = vhost_user_blk_pci_instance_init,
> > +    .class_init     = vhost_user_blk_pci_class_init,
> > +};
> > +#endif
> > +
> >  /* virtio-scsi-pci */
> >
> >  static Property virtio_scsi_pci_properties[] = {
> > @@ -2658,6 +2710,9 @@ static void virtio_pci_register_types(void)
> >      type_register_static(&virtio_9p_pci_info);
> >  #endif
> >      type_register_static(&virtio_blk_pci_info);
> > +#ifdef CONFIG_VHOST_USER_BLK
> > +    type_register_static(&vhost_user_blk_pci_info);
> > +#endif
> >      type_register_static(&virtio_scsi_pci_info);
> >      type_register_static(&virtio_balloon_pci_info);
> >      type_register_static(&virtio_serial_pci_info);
> > diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
> > index 69f5959..19a0d01 100644
> > --- a/hw/virtio/virtio-pci.h
> > +++ b/hw/virtio/virtio-pci.h
> > @@ -27,6 +27,9 @@
> >  #include "hw/virtio/virtio-gpu.h"
> >  #include "hw/virtio/virtio-crypto.h"
> >  #include "hw/virtio/vhost-user-scsi.h"
> > +#ifdef CONFIG_VHOST_USER_BLK
> > +#include "hw/virtio/vhost-user-blk.h"
> > +#endif
> >
> >  #ifdef CONFIG_VIRTFS
> >  #include "hw/9pfs/virtio-9p.h"
> > @@ -46,6 +49,7 @@ typedef struct VirtIOSerialPCI VirtIOSerialPCI;
> >  typedef struct VirtIONetPCI VirtIONetPCI;
> >  typedef struct VHostSCSIPCI VHostSCSIPCI;
> >  typedef struct VHostUserSCSIPCI VHostUserSCSIPCI;
> > +typedef struct VHostUserBlkPCI VHostUserBlkPCI;
> >  typedef struct VirtIORngPCI VirtIORngPCI;
> >  typedef struct VirtIOInputPCI VirtIOInputPCI;
> >  typedef struct VirtIOInputHIDPCI VirtIOInputHIDPCI;
> > @@ -241,6 +245,20 @@ struct VHostUserSCSIPCI {
> >      VHostUserSCSI vdev;
> >  };
> >
> > +#ifdef CONFIG_VHOST_USER_BLK
> > +/*
> > + * vhost-user-blk-pci: This extends VirtioPCIProxy.
> > + */
> > +#define TYPE_VHOST_USER_BLK_PCI "vhost-user-blk-pci"
> > +#define VHOST_USER_BLK_PCI(obj) \
> > +        OBJECT_CHECK(VHostUserBlkPCI, (obj), TYPE_VHOST_USER_BLK_PCI)
> > +
> > +struct VHostUserBlkPCI {
> > +    VirtIOPCIProxy parent_obj;
> > +    VHostUserBlk vdev;
> > +};
> > +#endif
> > +
> >  /*
> >   * virtio-blk-pci: This extends VirtioPCIProxy.
> >   */
> > diff --git a/include/hw/virtio/vhost-user-blk.h
> > b/include/hw/virtio/vhost-user-blk.h
> > new file mode 100644
> > index 0000000..77d20f0
> > --- /dev/null
> > +++ b/include/hw/virtio/vhost-user-blk.h
> > @@ -0,0 +1,40 @@
> > +/*
> > + * vhost-user-blk host device
> > + * Copyright IBM, Corp. 2011
> > + * Copyright(C) 2017 Intel Corporation.
> > + *
> > + * Authors:
> > + *  Stefan Hajnoczi <address@hidden>
> > + *  Changpeng Liu <address@hidden>
> > + *
> > + * This work is licensed under the terms of the GNU LGPL, version 2 or
> > later.
> > + * See the COPYING.LIB file in the top-level directory.
> > + *
> > + */
> > +
> > +#ifndef VHOST_USER_BLK_H
> > +#define VHOST_USER_BLK_H
> > +
> > +#include "standard-headers/linux/virtio_blk.h"
> > +#include "qemu-common.h"
> > +#include "hw/qdev.h"
> > +#include "hw/block/block.h"
> > +#include "chardev/char-fe.h"
> > +#include "hw/virtio/vhost.h"
> > +
> > +#define TYPE_VHOST_USER_BLK "vhost-user-blk"
> > +#define VHOST_USER_BLK(obj) \
> > +        OBJECT_CHECK(VHostUserBlk, (obj), TYPE_VHOST_USER_BLK)
> > +
> > +typedef struct VHostUserBlk {
> > +    VirtIODevice parent_obj;
> > +    CharBackend chardev;
> > +    int32_t bootindex;
> > +    uint64_t host_features;
> > +    struct virtio_blk_config blkcfg;
> > +    uint16_t num_queues;
> > +    uint32_t queue_size;
> > +    struct vhost_dev dev;
> > +} VHostUserBlk;
> > +
> > +#endif
> > --
> > 1.9.3
> >
> >