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Re: [RFC PATCH v2 1/1] block: add vhost-blk backend
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From: |
Michael S. Tsirkin |
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Subject: |
Re: [RFC PATCH v2 1/1] block: add vhost-blk backend |
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Date: |
Thu, 13 Oct 2022 17:01:53 -0400 |
On Thu, Oct 13, 2022 at 11:31:30PM +0300, Andrey Zhadchenko wrote:
> Although QEMU virtio is quite fast, there is still some room for
> improvements. Disk latency can be reduced if we handle virito-blk requests
> in host kernel istead of passing them to QEMU. The patch adds vhost-blk
> backend which sets up vhost-blk kernel module to process requests.
>
> test setup and results:
> fio --direct=1 --rw=randread --bs=4k --ioengine=libaio --iodepth=128
> QEMU drive options: cache=none
> filesystem: xfs
>
> SSD:
> | randread, IOPS | randwrite, IOPS |
> Host | 95.8k | 85.3k |
> QEMU virtio | 61.5k | 79.9k |
> QEMU vhost-blk | 95.6k | 84.3k |
>
> RAMDISK (vq == vcpu == numjobs):
> | randread, IOPS | randwrite, IOPS |
> virtio, 1vcpu | 133k | 133k |
> virtio, 2vcpu | 305k | 306k |
> virtio, 4vcpu | 310k | 298k |
> virtio, 8vcpu | 271k | 252k |
> vhost-blk, 1vcpu | 110k | 113k |
> vhost-blk, 2vcpu | 247k | 252k |
> vhost-blk, 4vcpu | 558k | 556k |
> vhost-blk, 8vcpu | 576k | 575k | *single kernel thread
> vhost-blk, 8vcpu | 803k | 779k | *two kernel threads
>
> v2:
> - fix g_new() to g_new0() for vq allocations
> - add multithreading support
> - fix last agrument in vhost_dev_init()
> - kick all vqueues in start, not only the first one
>
> Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko@virtuozzo.com>
Could we get feedback from block maintainers on this please?
> ---
> hw/block/Kconfig | 5 +
> hw/block/meson.build | 4 +
> hw/block/vhost-blk.c | 403 ++++++++++++++++++++++++++++++++++
> hw/virtio/meson.build | 3 +
> hw/virtio/vhost-blk-pci.c | 102 +++++++++
> include/hw/virtio/vhost-blk.h | 52 +++++
> meson.build | 6 +
> meson_options.txt | 2 +
> scripts/meson-buildoptions.sh | 3 +
> 9 files changed, 580 insertions(+)
> create mode 100644 hw/block/vhost-blk.c
> create mode 100644 hw/virtio/vhost-blk-pci.c
> create mode 100644 include/hw/virtio/vhost-blk.h
>
> diff --git a/hw/block/Kconfig b/hw/block/Kconfig
> index 9e8f28f982..b4286ad10e 100644
> --- a/hw/block/Kconfig
> +++ b/hw/block/Kconfig
> @@ -36,6 +36,11 @@ config VIRTIO_BLK
> default y
> depends on VIRTIO
>
> +config VHOST_BLK
> + bool
> + default y
> + depends on VIRTIO && LINUX
> +
> config VHOST_USER_BLK
> bool
> # Only PCI devices are provided for now
> diff --git a/hw/block/meson.build b/hw/block/meson.build
> index 2389326112..caf9bedff3 100644
> --- a/hw/block/meson.build
> +++ b/hw/block/meson.build
> @@ -19,4 +19,8 @@ softmmu_ss.add(when: 'CONFIG_TC58128', if_true:
> files('tc58128.c'))
> specific_ss.add(when: 'CONFIG_VIRTIO_BLK', if_true: files('virtio-blk.c'))
> specific_ss.add(when: 'CONFIG_VHOST_USER_BLK', if_true:
> files('vhost-user-blk.c'))
>
> +if have_vhost_blk
> + specific_ss.add(files('vhost-blk.c'))
> +endif
> +
> subdir('dataplane')
> diff --git a/hw/block/vhost-blk.c b/hw/block/vhost-blk.c
> new file mode 100644
> index 0000000000..2ebd09299c
> --- /dev/null
> +++ b/hw/block/vhost-blk.c
> @@ -0,0 +1,403 @@
> +/*
> + * Copyright (c) 2022 Virtuozzo International GmbH.
> + * Author: Andrey Zhadchenko <andrey.zhadchenko@virtuozzo.com>
> + *
> + * vhost-blk is host kernel accelerator for virtio-blk.
> + *
> + * 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 "qom/object.h"
> +#include "hw/qdev-core.h"
> +#include "hw/boards.h"
> +#include "hw/virtio/vhost.h"
> +#include "hw/virtio/vhost-blk.h"
> +#include "hw/virtio/virtio.h"
> +#include "hw/virtio/virtio-blk.h"
> +#include "hw/virtio/virtio-bus.h"
> +#include "hw/virtio/virtio-access.h"
> +#include "hw/virtio/virtio-pci.h"
> +#include "sysemu/sysemu.h"
> +#include "linux-headers/linux/vhost.h"
> +#include <sys/ioctl.h>
> +#include <linux/fs.h>
> +
> +static int vhost_blk_start(VirtIODevice *vdev)
> +{
> + VHostBlk *s = VHOST_BLK(vdev);
> + struct vhost_vring_file backend;
> + int ret, i, nworkers;
> + int *fd = blk_bs(s->conf.conf.blk)->file->bs->opaque;
> + BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> + VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> +
> + if (!k->set_guest_notifiers) {
> + error_report("vhost-blk: binding does not support guest notifiers");
> + return -ENOSYS;
> + }
> +
> + if (s->vhost_started) {
> + return 0;
> + }
> +
> + if (ioctl(s->vhostfd, VHOST_SET_OWNER, NULL)) {
> + error_report("vhost-blk: unable to set owner");
> + return -ENOSYS;
> + }
> +
> + nworkers = s->conf.num_threads;
> + if (nworkers != 1 && ioctl(s->vhostfd, VHOST_SET_NWORKERS, &nworkers)) {
> + error_report("vhost-blk: unable to set number of kernel threads");
> + return -ENOSYS;
> + }
> +
> + ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, true);
> + if (ret < 0) {
> + error_report("vhost-blk: unable to bind guest notifiers");
> + goto out;
> + }
> +
> + ret = vhost_dev_enable_notifiers(&s->dev, vdev);
> + if (ret < 0) {
> + error_report("vhost-blk: unable to enable dev notifiers", errno);
> + return ret;
> + }
> +
> + s->dev.acked_features = vdev->guest_features & s->dev.backend_features;
> +
> + ret = vhost_dev_start(&s->dev, vdev);
> + if (ret < 0) {
> + error_report("vhost-blk: unable to start vhost dev");
> + return ret;
> + }
> +
> + memset(&backend, 0, sizeof(backend));
> + backend.index = 0;
> + backend.fd = *fd;
> + if (ioctl(s->vhostfd, VHOST_BLK_SET_BACKEND, &backend)) {
> + error_report("vhost-blk: unable to set backend");
> + ret = -errno;
> + goto out;
> + }
> +
> + for (i = 0; i < s->dev.nvqs; i++) {
> + vhost_virtqueue_mask(&s->dev, vdev, i, false);
> + }
> +
> + for (i = 0; i < s->dev.nvqs; i++) {
> +
> event_notifier_set(virtio_queue_get_host_notifier(virtio_get_queue(vdev, i)));
> + }
> +
> + s->vhost_started = true;
> +
> + return 0;
> +
> +out:
> + vhost_dev_stop(&s->dev, vdev);
> + return ret;
> +
> +}
> +
> +static void vhost_blk_stop(VirtIODevice *vdev)
> +{
> + BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> + VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> + VHostBlk *s = VHOST_BLK(vdev);
> + int ret;
> +
> + if (!s->vhost_started) {
> + return;
> + }
> +
> + ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
> + if (ret < 0) {
> + error_report("vhost-blk: unable to unbind guest notifiers");
> + }
> + vhost_dev_disable_notifiers(&s->dev, vdev);
> + vhost_dev_stop(&s->dev, vdev);
> +
> + s->vhost_started = false;
> +}
> +
> +static void vhost_blk_reset(VirtIODevice *vdev)
> +{
> + VHostBlk *s = VHOST_BLK(vdev);
> + int ret;
> +
> + vhost_blk_stop(vdev);
> + ret = ioctl(s->vhostfd, VHOST_RESET_OWNER, NULL);
> + if (ret && errno != EPERM) {
> + error_report("vhost-blk: failed to reset owner %d", errno);
> + }
> +}
> +
> +static void vhost_blk_set_status(VirtIODevice *vdev, uint8_t status)
> +{
> + if (status & (VIRTIO_CONFIG_S_NEEDS_RESET | VIRTIO_CONFIG_S_FAILED)) {
> + vhost_blk_stop(vdev);
> + return;
> + }
> +
> + if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
> + return;
> + }
> +
> + if (vhost_blk_start(vdev)) {
> + error_report("vhost-blk: failed to start");
> + }
> +}
> +
> +static void vhost_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
> +{
> +}
> +
> +static void vhost_blk_device_realize(DeviceState *dev, Error **errp)
> +{
> + VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> + VHostBlk *s = VHOST_BLK(vdev);
> + VhostBlkConf *conf = &s->conf;
> + int i, ret;
> +
> + if (!conf->conf.blk) {
> + error_setg(errp, "vhost-blk: drive property not set");
> + return;
> + }
> +
> + if (!blk_is_inserted(conf->conf.blk)) {
> + error_setg(errp, "vhost-blk: device needs media, but drive is
> empty");
> + return;
> + }
> +
> + if (conf->num_queues == VHOST_BLK_AUTO_NUM_QUEUES) {
> + conf->num_queues = MIN(virtio_pci_optimal_num_queues(0),
> + VHOST_BLK_MAX_QUEUES);
> + }
> +
> + if (!conf->num_queues) {
> + error_setg(errp, "vhost-blk: num-queues property must be larger than
> 0");
> + return;
> + }
> +
> + if (conf->queue_size <= 2) {
> + error_setg(errp, "vhost-blk: invalid queue-size property (%" PRIu16
> "), "
> + "must be > 2", conf->queue_size);
> + return;
> + }
> +
> + if (!is_power_of_2(conf->queue_size) ||
> + conf->queue_size > VIRTQUEUE_MAX_SIZE) {
> + error_setg(errp, "vhost_blk: invalid queue-size property (%" PRIu16
> "), "
> + "must be a power of 2 (max %d)",
> + conf->queue_size, VIRTQUEUE_MAX_SIZE);
> + return;
> + }
> +
> + if (!blkconf_apply_backend_options(&conf->conf,
> +
> !blk_supports_write_perm(conf->conf.blk),
> + true, errp)) {
> + return;
> + }
> +
> + if (!blkconf_geometry(&conf->conf, NULL, 65535, 255, 255, errp)) {
> + return;
> + }
> +
> + if (!blkconf_blocksizes(&conf->conf, errp)) {
> + return;
> + }
> +
> + s->dev.nvqs = conf->num_queues;
> + s->dev.max_queues = conf->num_queues;
> + s->dev.vqs = g_new0(struct vhost_virtqueue, s->dev.nvqs);
> + s->dev.vq_index = 0;
> +
> + virtio_init(vdev, VIRTIO_ID_BLOCK, sizeof(struct virtio_blk_config));
> +
> + for (i = 0; i < conf->num_queues; i++) {
> + virtio_add_queue(vdev, conf->queue_size, vhost_blk_handle_output);
> + }
> +
> + s->vhostfd = open("/dev/vhost-blk", O_RDWR);
> + if (s->vhostfd < 0) {
> + error_setg(errp, "vhost-blk: unable to open /dev/vhost-blk");
> + goto cleanup;
> + }
> +
> + s->dev.acked_features = 0;
> + ret = ioctl(s->vhostfd, VHOST_GET_FEATURES, &s->dev.backend_features);
> + if (ret < 0) {
> + error_setg(errp, "vhost-blk: unable to get backend features");
> + goto cleanup;
> + }
> +
> + ret = vhost_dev_init(&s->dev, (void *)((size_t)s->vhostfd),
> + VHOST_BACKEND_TYPE_KERNEL, 0, NULL);
> + if (ret < 0) {
> + error_setg(errp, "vhost-blk: vhost initialization failed: %s",
> + strerror(-ret));
> + goto cleanup;
> + }
> +
> + return;
> +
> +cleanup:
> + g_free(s->dev.vqs);
> + close(s->vhostfd);
> + for (i = 0; i < conf->num_queues; i++) {
> + virtio_del_queue(vdev, i);
> + }
> + virtio_cleanup(vdev);
> + return;
> +}
> +
> +static void vhost_blk_device_unrealize(DeviceState *dev)
> +{
> + VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> + VHostBlk *s = VHOST_BLK(dev);
> +
> + vhost_blk_set_status(vdev, 0);
> + vhost_dev_cleanup(&s->dev);
> + g_free(s->dev.vqs);
> + virtio_cleanup(vdev);
> +}
> +
> +static const int user_feature_bits[] = {
> + VIRTIO_BLK_F_FLUSH,
> + VIRTIO_RING_F_INDIRECT_DESC,
> + VIRTIO_RING_F_EVENT_IDX,
> + VHOST_INVALID_FEATURE_BIT
> +};
> +
> +
> +static uint64_t vhost_blk_get_features(VirtIODevice *vdev,
> + uint64_t features,
> + Error **errp)
> +{
> + VHostBlk *s = VHOST_BLK(vdev);
> + uint64_t res;
> +
> + features |= s->host_features;
> +
> + virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE);
> + virtio_add_feature(&features, VIRTIO_BLK_F_SEG_MAX);
> + virtio_add_feature(&features, VIRTIO_BLK_F_GEOMETRY);
> + virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY);
> + virtio_add_feature(&features, VIRTIO_BLK_F_SIZE_MAX);
> +
> + virtio_add_feature(&features, VIRTIO_F_VERSION_1);
> +
> + if (!blk_is_writable(s->conf.conf.blk)) {
> + virtio_add_feature(&features, VIRTIO_BLK_F_RO);
> + }
> +
> + if (s->conf.num_queues > 1) {
> + virtio_add_feature(&features, VIRTIO_BLK_F_MQ);
> + }
> +
> + res = vhost_get_features(&s->dev, user_feature_bits, features);
> +
> + return res;
> +}
> +
> +static void vhost_blk_update_config(VirtIODevice *vdev, uint8_t *config)
> +{
> + VHostBlk *s = VHOST_BLK(vdev);
> + BlockConf *conf = &s->conf.conf;
> + struct virtio_blk_config blkcfg;
> + uint64_t capacity;
> + int64_t length;
> + int blk_size = conf->logical_block_size;
> +
> + blk_get_geometry(s->conf.conf.blk, &capacity);
> + memset(&blkcfg, 0, sizeof(blkcfg));
> + virtio_stq_p(vdev, &blkcfg.capacity, capacity);
> + virtio_stl_p(vdev, &blkcfg.seg_max, s->conf.queue_size - 2);
> + virtio_stw_p(vdev, &blkcfg.geometry.cylinders, conf->cyls);
> + virtio_stl_p(vdev, &blkcfg.blk_size, blk_size);
> + blkcfg.geometry.heads = conf->heads;
> +
> + length = blk_getlength(s->conf.conf.blk);
> + if (length > 0 && length / conf->heads / conf->secs % blk_size) {
> + unsigned short mask;
> +
> + mask = (s->conf.conf.logical_block_size / BDRV_SECTOR_SIZE) - 1;
> + blkcfg.geometry.sectors = conf->secs & ~mask;
> + } else {
> + blkcfg.geometry.sectors = conf->secs;
> + }
> +
> + blkcfg.size_max = 0;
> + blkcfg.physical_block_exp = get_physical_block_exp(conf);
> + blkcfg.alignment_offset = 0;
> + virtio_stw_p(vdev, &blkcfg.num_queues, s->conf.num_queues);
> +
> + memcpy(config, &blkcfg, sizeof(struct virtio_blk_config));
> +}
> +
> +static Property vhost_blk_properties[] = {
> + DEFINE_BLOCK_PROPERTIES(VHostBlk, conf.conf),
> + DEFINE_PROP_UINT16("num-queues", VHostBlk, conf.num_queues,
> + VHOST_BLK_AUTO_NUM_QUEUES),
> + DEFINE_PROP_UINT16("queue-size", VHostBlk, conf.queue_size, 256),
> + DEFINE_PROP_UINT16("num-threads", VHostBlk, conf.num_threads, 1),
> +/* Discard and write-zeroes not yet implemented in kernel module */
> + DEFINE_PROP_BIT64("discard", VHostBlk, host_features,
> + VIRTIO_BLK_F_DISCARD, false),
> + DEFINE_PROP_BIT64("write-zeroes", VHostBlk, host_features,
> + VIRTIO_BLK_F_WRITE_ZEROES, false),
> + DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static const VMStateDescription vmstate_vhost_blk = {
> + .name = "vhost-blk",
> + .minimum_version_id = 1,
> + .version_id = 1,
> + .fields = (VMStateField[]) {
> + VMSTATE_VIRTIO_DEVICE,
> + VMSTATE_END_OF_LIST()
> + },
> +};
> +
> +static void vhost_blk_class_init(ObjectClass *klass, void *data)
> +{
> + DeviceClass *dc = DEVICE_CLASS(klass);
> + VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
> +
> + device_class_set_props(dc, vhost_blk_properties);
> + dc->vmsd = &vmstate_vhost_blk;
> + set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
> + vdc->realize = vhost_blk_device_realize;
> + vdc->unrealize = vhost_blk_device_unrealize;
> + vdc->get_config = vhost_blk_update_config;
> + vdc->get_features = vhost_blk_get_features;
> + vdc->set_status = vhost_blk_set_status;
> + vdc->reset = vhost_blk_reset;
> +}
> +
> +static void vhost_blk_instance_init(Object *obj)
> +{
> + VHostBlk *s = VHOST_BLK(obj);
> +
> + device_add_bootindex_property(obj, &s->conf.conf.bootindex,
> + "bootindex", "/disk@0,0",
> + DEVICE(obj));
> +}
> +
> +static const TypeInfo vhost_blk_info = {
> + .name = TYPE_VHOST_BLK,
> + .parent = TYPE_VIRTIO_DEVICE,
> + .instance_size = sizeof(VHostBlk),
> + .instance_init = vhost_blk_instance_init,
> + .class_init = vhost_blk_class_init,
> +};
> +
> +static void virtio_register_types(void)
> +{
> + type_register_static(&vhost_blk_info);
> +}
> +
> +type_init(virtio_register_types)
> diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
> index 7e8877fd64..fb2c0e7242 100644
> --- a/hw/virtio/meson.build
> +++ b/hw/virtio/meson.build
> @@ -40,6 +40,9 @@ virtio_pci_ss.add(when: 'CONFIG_VHOST_USER_RNG', if_true:
> files('vhost-user-rng-
> virtio_pci_ss.add(when: 'CONFIG_VHOST_USER_SCSI', if_true:
> files('vhost-user-scsi-pci.c'))
> virtio_pci_ss.add(when: 'CONFIG_VHOST_SCSI', if_true:
> files('vhost-scsi-pci.c'))
> virtio_pci_ss.add(when: 'CONFIG_VHOST_USER_FS', if_true:
> files('vhost-user-fs-pci.c'))
> +if have_vhost_blk
> + virtio_ss.add(files('vhost-blk-pci.c'))
> +endif
>
> virtio_pci_ss.add(when: 'CONFIG_VIRTIO_CRYPTO', if_true:
> files('virtio-crypto-pci.c'))
> virtio_pci_ss.add(when: 'CONFIG_VIRTIO_INPUT_HOST', if_true:
> files('virtio-input-host-pci.c'))
> diff --git a/hw/virtio/vhost-blk-pci.c b/hw/virtio/vhost-blk-pci.c
> new file mode 100644
> index 0000000000..f3b6e112b4
> --- /dev/null
> +++ b/hw/virtio/vhost-blk-pci.c
> @@ -0,0 +1,102 @@
> +/*
> + * Copyright (c) 2022 Virtuozzo International GmbH.
> + * Author: Andrey Zhadchenko <andrey.zhadchenko@virtuozzo.com>
> + *
> + * vhost-blk PCI bindings
> + *
> + * 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 "standard-headers/linux/virtio_pci.h"
> +#include "hw/virtio/virtio.h"
> +#include "hw/virtio/vhost-blk.h"
> +#include "hw/pci/pci.h"
> +#include "hw/qdev-properties.h"
> +#include "qapi/error.h"
> +#include "qemu/error-report.h"
> +#include "qemu/module.h"
> +#include "hw/virtio/virtio-pci.h"
> +#include "qom/object.h"
> +
> +typedef struct VHostBlkPCI VHostBlkPCI;
> +
> +/*
> + * vhost-blk-pci: This extends VirtioPCIProxy.
> + */
> +#define TYPE_VHOST_BLK_PCI "vhost-blk-pci-base"
> +DECLARE_INSTANCE_CHECKER(VHostBlkPCI, VHOST_BLK_PCI,
> + TYPE_VHOST_BLK_PCI)
> +
> +struct VHostBlkPCI {
> + VirtIOPCIProxy parent_obj;
> + VHostBlk vdev;
> +};
> +
> +static Property vhost_blk_pci_properties[] = {
> + DEFINE_PROP_UINT32("class", VirtIOPCIProxy, class_code, 0),
> + DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors,
> + DEV_NVECTORS_UNSPECIFIED),
> + DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static void vhost_blk_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
> +{
> + VHostBlkPCI *dev = VHOST_BLK_PCI(vpci_dev);
> + DeviceState *vdev = DEVICE(&dev->vdev);
> +
> + if (dev->vdev.conf.num_queues == VHOST_BLK_AUTO_NUM_QUEUES) {
> + dev->vdev.conf.num_queues = MIN(virtio_pci_optimal_num_queues(0),
> + VHOST_BLK_MAX_QUEUES);
> + }
> +
> + if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
> + vpci_dev->nvectors = dev->vdev.conf.num_queues + 1;
> + }
> +
> + qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
> +}
> +
> +static void vhost_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);
> + device_class_set_props(dc, vhost_blk_pci_properties);
> + k->realize = vhost_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_blk_pci_instance_init(Object *obj)
> +{
> + VHostBlkPCI *dev = VHOST_BLK_PCI(obj);
> +
> + virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
> + TYPE_VHOST_BLK);
> + object_property_add_alias(obj, "bootindex", OBJECT(&dev->vdev),
> + "bootindex");
> +}
> +
> +static const VirtioPCIDeviceTypeInfo vhost_blk_pci_info = {
> + .base_name = TYPE_VHOST_BLK_PCI,
> + .generic_name = "vhost-blk-pci",
> + .transitional_name = "vhost-blk-pci-transitional",
> + .non_transitional_name = "vhost-blk-pci-non-transitional",
> + .instance_size = sizeof(VHostBlkPCI),
> + .instance_init = vhost_blk_pci_instance_init,
> + .class_init = vhost_blk_pci_class_init,
> +};
> +
> +static void vhost_blk_pci_register(void)
> +{
> + virtio_pci_types_register(&vhost_blk_pci_info);
> +}
> +
> +type_init(vhost_blk_pci_register)
> diff --git a/include/hw/virtio/vhost-blk.h b/include/hw/virtio/vhost-blk.h
> new file mode 100644
> index 0000000000..58f847077d
> --- /dev/null
> +++ b/include/hw/virtio/vhost-blk.h
> @@ -0,0 +1,52 @@
> +/*
> + * Copyright (c) 2022 Virtuozzo International GmbH.
> + * Author: Andrey Zhadchenko <andrey.zhadchenko@virtuozzo.com>
> + *
> + * vhost-blk is host kernel accelerator for virtio-blk.
> + *
> + * 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_BLK_H
> +#define VHOST_BLK_H
> +
> +#include "standard-headers/linux/virtio_blk.h"
> +#include "hw/block/block.h"
> +#include "hw/virtio/vhost.h"
> +#include "sysemu/block-backend.h"
> +
> +#define TYPE_VHOST_BLK "vhost-blk"
> +#define VHOST_BLK(obj) \
> + OBJECT_CHECK(VHostBlk, (obj), TYPE_VHOST_BLK)
> +
> +#define VHOST_BLK_AUTO_NUM_QUEUES UINT16_MAX
> +#define VHOST_BLK_MAX_QUEUES 16
> +
> +/*
> + * normally should be visible from imported headers
> + * temporary define here to simplify development
> + */
> +#define VHOST_BLK_SET_BACKEND _IOW(VHOST_VIRTIO, 0xFF, \
> + struct vhost_vring_file)
> +#define VHOST_SET_NWORKERS _IOW(VHOST_VIRTIO, 0x1F, int)
> +
> +typedef struct VhostBlkConf {
> + BlockConf conf;
> + uint16_t num_queues;
> + uint16_t queue_size;
> + uint16_t num_threads;
> +} VhostBlkConf;
> +
> +typedef struct VHostBlk {
> + VirtIODevice parent_obj;
> + VhostBlkConf conf;
> + uint64_t host_features;
> + uint64_t decided_features;
> + struct virtio_blk_config blkcfg;
> + int vhostfd;
> + struct vhost_dev dev;
> + bool vhost_started;
> +} VHostBlk;
> +
> +#endif
> diff --git a/meson.build b/meson.build
> index 8a8c415fc1..886b778079 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -336,6 +336,9 @@ have_vhost_kernel = get_option('vhost_kernel') \
> have_vhost_user_crypto = get_option('vhost_crypto') \
> .require(have_vhost_user,
> error_message: 'vhost-crypto requires vhost-user to be
> enabled').allowed()
> +have_vhost_blk = get_option('vhost_blk') \
> + .require(targetos == 'linux',
> + error_message: 'vhost-kernel is only available on
> Linux').allowed()
>
> have_vhost = have_vhost_user or have_vhost_vdpa or have_vhost_kernel
>
> @@ -1814,6 +1817,7 @@ config_host_data.set('CONFIG_VHOST_KERNEL',
> have_vhost_kernel)
> config_host_data.set('CONFIG_VHOST_USER', have_vhost_user)
> config_host_data.set('CONFIG_VHOST_CRYPTO', have_vhost_user_crypto)
> config_host_data.set('CONFIG_VHOST_VDPA', have_vhost_vdpa)
> +config_host_data.set('CONFIG_VHOST_BLK', have_vhost_blk)
> config_host_data.set('CONFIG_VMNET', vmnet.found())
> config_host_data.set('CONFIG_VHOST_USER_BLK_SERVER',
> have_vhost_user_blk_server)
> config_host_data.set('CONFIG_VDUSE_BLK_EXPORT', have_vduse_blk_export)
> @@ -2421,6 +2425,7 @@ host_kconfig = \
> (x11.found() ? ['CONFIG_X11=y'] : []) + \
> (have_vhost_user ? ['CONFIG_VHOST_USER=y'] : []) + \
> (have_vhost_vdpa ? ['CONFIG_VHOST_VDPA=y'] : []) + \
> + (have_vhost_blk ? ['CONFIG_VHOST_BLK=y'] : []) + \
> (have_vhost_kernel ? ['CONFIG_VHOST_KERNEL=y'] : []) + \
> (have_virtfs ? ['CONFIG_VIRTFS=y'] : []) + \
> ('CONFIG_LINUX' in config_host ? ['CONFIG_LINUX=y'] : []) + \
> @@ -3756,6 +3761,7 @@ summary_info += {'vhost-user support': have_vhost_user}
> summary_info += {'vhost-user-crypto support': have_vhost_user_crypto}
> summary_info += {'vhost-user-blk server support': have_vhost_user_blk_server}
> summary_info += {'vhost-vdpa support': have_vhost_vdpa}
> +summary_info += {'vhost-blk support': have_vhost_blk}
> summary_info += {'build guest agent': have_ga}
> summary(summary_info, bool_yn: true, section: 'Configurable features')
>
> diff --git a/meson_options.txt b/meson_options.txt
> index e58e158396..277bd49525 100644
> --- a/meson_options.txt
> +++ b/meson_options.txt
> @@ -251,6 +251,8 @@ option('vhost_crypto', type: 'feature', value: 'auto',
> description: 'vhost-user crypto backend support')
> option('vhost_vdpa', type: 'feature', value: 'auto',
> description: 'vhost-vdpa kernel backend support')
> +option('vhost_blk', type: 'feature', value: 'auto',
> + description: 'vhost-blk kernel backend support')
> option('vhost_user_blk_server', type: 'feature', value: 'auto',
> description: 'build vhost-user-blk server')
> option('virtfs', type: 'feature', value: 'auto',
> diff --git a/scripts/meson-buildoptions.sh b/scripts/meson-buildoptions.sh
> index 359b04e0e6..94afde8f6b 100644
> --- a/scripts/meson-buildoptions.sh
> +++ b/scripts/meson-buildoptions.sh
> @@ -156,6 +156,7 @@ meson_options_help() {
> printf "%s\n" ' vdi vdi image format support'
> printf "%s\n" ' vfio-user-server'
> printf "%s\n" ' vfio-user server support'
> + printf "%s\n" ' vhost-blk vhost-blk kernel backend support'
> printf "%s\n" ' vhost-crypto vhost-user crypto backend support'
> printf "%s\n" ' vhost-kernel vhost kernel backend support'
> printf "%s\n" ' vhost-net vhost-net kernel acceleration support'
> @@ -424,6 +425,8 @@ _meson_option_parse() {
> --disable-vdi) printf "%s" -Dvdi=disabled ;;
> --enable-vfio-user-server) printf "%s" -Dvfio_user_server=enabled ;;
> --disable-vfio-user-server) printf "%s" -Dvfio_user_server=disabled ;;
> + --enable-vhost-blk) printf "%s" -Dvhost_blk=enabled ;;
> + --disable-vhost-blk) printf "%s" -Dvhost_blk=disabled ;;
> --enable-vhost-crypto) printf "%s" -Dvhost_crypto=enabled ;;
> --disable-vhost-crypto) printf "%s" -Dvhost_crypto=disabled ;;
> --enable-vhost-kernel) printf "%s" -Dvhost_kernel=enabled ;;
> --
> 2.31.1