Re: [PATCH 3/3] vhost-vdpa-blk: Introduce vhost-vdpa-blk host device

[Jason Wang <jasowang@redhat.com>]

在 2021/4/9 下午4:17, Yongji Xie 写道:
> On Fri, Apr 9, 2021 at 2:02 PM Jason Wang <jasowang@redhat.com> wrote:
>>
>> 在 2021/4/8 下午6:12, Xie Yongji 写道:
>>> This commit introduces a new vhost-vdpa block device, which
>>> will set up a vDPA device specified by a "vdpa-dev" parameter,
>>> something like:
>>>
>>> qemu-system-x86_64 \
>>>       -device vhost-vdpa-blk-pci,vdpa-dev=/dev/vhost-vdpa-0
>>>
>>> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
>>> ---
>>>    hw/block/Kconfig                   |   5 +
>>>    hw/block/meson.build               |   1 +
>>>    hw/block/vhost-vdpa-blk.c          | 227 +++++++++++++++++++++++++++++
>>>    hw/virtio/meson.build              |   1 +
>>>    hw/virtio/vhost-vdpa-blk-pci.c     | 101 +++++++++++++
>>>    include/hw/virtio/vhost-vdpa-blk.h |  30 ++++
>>>    6 files changed, 365 insertions(+)
>>>    create mode 100644 hw/block/vhost-vdpa-blk.c
>>>    create mode 100644 hw/virtio/vhost-vdpa-blk-pci.c
>>>    create mode 100644 include/hw/virtio/vhost-vdpa-blk.h
>>>
>>> diff --git a/hw/block/Kconfig b/hw/block/Kconfig
>>> index 4fcd152166..4615a2c116 100644
>>> --- a/hw/block/Kconfig
>>> +++ b/hw/block/Kconfig
>>> @@ -41,5 +41,10 @@ config VHOST_USER_BLK
>>>        default y if VIRTIO_PCI
>>>        depends on VIRTIO && VHOST_USER && LINUX
>>>
>>> +config VHOST_VDPA_BLK
>>> +    bool
>>> +    default y if VIRTIO_PCI
>>> +    depends on VIRTIO && VHOST_VDPA && LINUX
>>> +
>>>    config SWIM
>>>        bool
>>> diff --git a/hw/block/meson.build b/hw/block/meson.build
>>> index 5862bda4cb..98f1fc330a 100644
>>> --- a/hw/block/meson.build
>>> +++ b/hw/block/meson.build
>>> @@ -17,5 +17,6 @@ softmmu_ss.add(when: 'CONFIG_NVME_PCI', if_true: files('nvme.c', 'nvme-ns.c', 'n
>>>
>>>    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-blk-common.c', 'vhost-user-blk.c'))
>>> +specific_ss.add(when: 'CONFIG_VHOST_VDPA_BLK', if_true: files('vhost-blk-common.c', 'vhost-vdpa-blk.c'))
>>>
>>>    subdir('dataplane')
>>> diff --git a/hw/block/vhost-vdpa-blk.c b/hw/block/vhost-vdpa-blk.c
>>> new file mode 100644
>>> index 0000000000..d5cbbbba10
>>> --- /dev/null
>>> +++ b/hw/block/vhost-vdpa-blk.c
>>> @@ -0,0 +1,227 @@
>>> +/*
>>> + * vhost-vdpa-blk host device
>>> + *
>>> + * Copyright (C) 2021 Bytedance Inc. and/or its affiliates. All rights reserved.
>>> + *
>>> + * Author:
>>> + *   Xie Yongji <xieyongji@bytedance.com>
>>> + *
>>> + * This work is licensed under the terms of the GNU GPL, version 2.  See
>>> + * the COPYING file in the top-level directory.
>>> + *
>>> + */
>>> +
>>> +#include "qemu/osdep.h"
>>> +#include "qapi/error.h"
>>> +#include "qemu/error-report.h"
>>> +#include "qemu/cutils.h"
>>> +#include "hw/qdev-core.h"
>>> +#include "hw/qdev-properties.h"
>>> +#include "hw/qdev-properties-system.h"
>>> +#include "hw/virtio/vhost.h"
>>> +#include "hw/virtio/vhost-vdpa-blk.h"
>>> +#include "hw/virtio/virtio.h"
>>> +#include "hw/virtio/virtio-bus.h"
>>> +#include "hw/virtio/virtio-access.h"
>>> +#include "sysemu/sysemu.h"
>>> +#include "sysemu/runstate.h"
>>> +
>>> +static const int vdpa_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_MQ,
>>> +    VIRTIO_BLK_F_RO,
>>> +    VIRTIO_BLK_F_FLUSH,
>>> +    VIRTIO_BLK_F_CONFIG_WCE,
>>> +    VIRTIO_BLK_F_DISCARD,
>>> +    VIRTIO_BLK_F_WRITE_ZEROES,
>>> +    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_vdpa_blk_set_status(VirtIODevice *vdev, uint8_t status)
>>> +{
>>> +    VHostVdpaBlk *s = VHOST_VDPA_BLK(vdev);
>>> +    VHostBlkCommon *vbc = VHOST_BLK_COMMON(s);
>>> +    bool should_start = virtio_device_started(vdev, status);
>>> +    int ret;
>>> +
>>> +    if (!vdev->vm_running) {
>>> +        should_start = false;
>>> +    }
>>> +
>>> +    if (vbc->dev.started == should_start) {
>>> +        return;
>>> +    }
>>> +
>>> +    if (should_start) {
>>> +        ret = vhost_blk_common_start(vbc);
>>> +        if (ret < 0) {
>>> +            error_report("vhost-vdpa-blk: vhost start failed: %s",
>>> +                         strerror(-ret));
>>> +        }
>>> +    } else {
>>> +        vhost_blk_common_stop(vbc);
>>> +    }
>>> +
>>> +}
>>> +
>>> +static void vhost_vdpa_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
>>> +{
>>> +    VHostVdpaBlk *s = VHOST_VDPA_BLK(vdev);
>>> +    VHostBlkCommon *vbc = VHOST_BLK_COMMON(s);
>>> +    int i, ret;
>>
>> I believe we should never reach here, the backend should poll the
>> notifier and trigger vq handler there after DRIVER_OK?
>>
> Some legacy virtio-blk driver (virtio 0.9) will do that. Kick before
> set DRIVER_OK.


Ok, I see, but any reason:

1) we need start vhost-blk
2) the relay is not done per vq but per device?


>
>>> +
>>> +    if (!vdev->start_on_kick) {
>>> +        return;
>>> +    }
>>> +
>>> +    if (vbc->dev.started) {
>>> +        return;
>>> +    }
>>> +
>>> +    ret = vhost_blk_common_start(vbc);
>>> +    if (ret < 0) {
>>> +        error_report("vhost-vdpa-blk: vhost start failed: %s",
>>> +                     strerror(-ret));
>>> +        return;
>>> +    }
>>> +
>>> +    /* Kick right away to begin processing requests already in vring */
>>> +    for (i = 0; i < vbc->dev.nvqs; i++) {
>>> +        VirtQueue *kick_vq = virtio_get_queue(vdev, i);
>>> +
>>> +        if (!virtio_queue_get_desc_addr(vdev, i)) {
>>> +            continue;
>>> +        }
>>> +        event_notifier_set(virtio_queue_get_host_notifier(kick_vq));
>>> +    }
>>> +}
>>> +
>>> +static void vhost_vdpa_blk_device_realize(DeviceState *dev, Error **errp)
>>> +{
>>> +    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
>>> +    VHostVdpaBlk *s = VHOST_VDPA_BLK(vdev);
>>> +    VHostBlkCommon *vbc = VHOST_BLK_COMMON(s);
>>> +    Error *err = NULL;
>>> +    int ret;
>>> +
>>> +    s->vdpa.device_fd = qemu_open_old(s->vdpa_dev, O_RDWR);
>>> +    if (s->vdpa.device_fd == -1) {
>>> +        error_setg(errp, "vhost-vdpa-blk: open %s failed: %s",
>>> +                   s->vdpa_dev, strerror(errno));
>>> +        return;
>>> +    }
>>> +
>>> +    vhost_blk_common_realize(vbc, vhost_vdpa_blk_handle_output, &err);
>>> +    if (err != NULL) {
>>> +        error_propagate(errp, err);
>>> +        goto blk_err;
>>> +    }
>>> +
>>> +    vbc->vhost_vqs = g_new0(struct vhost_virtqueue, vbc->num_queues);
>>> +    vbc->dev.nvqs = vbc->num_queues;
>>> +    vbc->dev.vqs = vbc->vhost_vqs;
>>> +    vbc->dev.vq_index = 0;
>>> +    vbc->dev.backend_features = 0;
>>> +    vbc->started = false;
>>> +
>>> +    vhost_dev_set_config_notifier(&vbc->dev, &blk_ops);
>>> +
>>> +    ret = vhost_dev_init(&vbc->dev, &s->vdpa, VHOST_BACKEND_TYPE_VDPA, 0);
>>> +    if (ret < 0) {
>>> +        error_setg(errp, "vhost-vdpa-blk: vhost initialization failed: %s",
>>> +                   strerror(-ret));
>>> +        goto init_err;
>>> +    }
>>> +
>>> +    ret = vhost_dev_get_config(&vbc->dev, (uint8_t *)&vbc->blkcfg,
>>> +                               sizeof(struct virtio_blk_config));
>>> +    if (ret < 0) {
>>> +        error_setg(errp, "vhost-vdpa-blk: get block config failed");
>>> +        goto config_err;
>>> +    }
>>> +
>>> +    return;
>>> +config_err:
>>> +    vhost_dev_cleanup(&vbc->dev);
>>> +init_err:
>>> +    vhost_blk_common_unrealize(vbc);
>>> +blk_err:
>>> +    close(s->vdpa.device_fd);
>>> +}
>>> +
>>> +static void vhost_vdpa_blk_device_unrealize(DeviceState *dev)
>>> +{
>>> +    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
>>> +    VHostVdpaBlk *s = VHOST_VDPA_BLK(dev);
>>> +    VHostBlkCommon *vbc = VHOST_BLK_COMMON(s);
>>> +
>>> +    virtio_set_status(vdev, 0);
>>> +    vhost_dev_cleanup(&vbc->dev);
>>> +    vhost_blk_common_unrealize(vbc);
>>> +    close(s->vdpa.device_fd);
>>> +}
>>> +
>>> +static void vhost_vdpa_blk_instance_init(Object *obj)
>>> +{
>>> +    VHostBlkCommon *vbc = VHOST_BLK_COMMON(obj);
>>> +
>>> +    vbc->feature_bits = vdpa_feature_bits;
>>> +
>>> +    device_add_bootindex_property(obj, &vbc->bootindex, "bootindex",
>>> +                                  "/disk@0,0", DEVICE(obj));
>>> +}
>>> +
>>> +static const VMStateDescription vmstate_vhost_vdpa_blk = {
>>> +    .name = "vhost-vdpa-blk",
>>> +    .minimum_version_id = 1,
>>> +    .version_id = 1,
>>> +    .fields = (VMStateField[]) {
>>> +        VMSTATE_VIRTIO_DEVICE,
>>> +        VMSTATE_END_OF_LIST()
>>> +    },
>>> +};
>>> +
>>> +static Property vhost_vdpa_blk_properties[] = {
>>> +    DEFINE_PROP_STRING("vdpa-dev", VHostVdpaBlk, vdpa_dev),
>>> +    DEFINE_PROP_UINT16("num-queues", VHostBlkCommon, num_queues,
>>> +                       VHOST_BLK_AUTO_NUM_QUEUES),
>>> +    DEFINE_PROP_UINT32("queue-size", VHostBlkCommon, queue_size, 256),
>>> +    DEFINE_PROP_BIT("config-wce", VHostBlkCommon, config_wce, 0, true),
>>> +    DEFINE_PROP_END_OF_LIST(),
>>> +};
>>> +
>>> +static void vhost_vdpa_blk_class_init(ObjectClass *klass, void *data)
>>> +{
>>> +    DeviceClass *dc = DEVICE_CLASS(klass);
>>> +    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
>>> +
>>> +    device_class_set_props(dc, vhost_vdpa_blk_properties);
>>> +    dc->vmsd = &vmstate_vhost_vdpa_blk;
>>> +    set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
>>> +    vdc->realize = vhost_vdpa_blk_device_realize;
>>> +    vdc->unrealize = vhost_vdpa_blk_device_unrealize;
>>> +    vdc->set_status = vhost_vdpa_blk_set_status;
>>> +}
>>> +
>>> +static const TypeInfo vhost_vdpa_blk_info = {
>>> +    .name = TYPE_VHOST_VDPA_BLK,
>>> +    .parent = TYPE_VHOST_BLK_COMMON,
>>> +    .instance_size = sizeof(VHostVdpaBlk),
>>> +    .instance_init = vhost_vdpa_blk_instance_init,
>>> +    .class_init = vhost_vdpa_blk_class_init,
>>> +};
>>> +
>>> +static void virtio_register_types(void)
>>> +{
>>> +    type_register_static(&vhost_vdpa_blk_info);
>>> +}
>>> +
>>> +type_init(virtio_register_types)
>>> diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
>>> index fbff9bc9d4..f02bea65a2 100644
>>> --- a/hw/virtio/meson.build
>>> +++ b/hw/virtio/meson.build
>>> @@ -30,6 +30,7 @@ virtio_pci_ss = ss.source_set()
>>>    virtio_pci_ss.add(when: 'CONFIG_VHOST_VSOCK', if_true: files('vhost-vsock-pci.c'))
>>>    virtio_pci_ss.add(when: 'CONFIG_VHOST_USER_VSOCK', if_true: files('vhost-user-vsock-pci.c'))
>>>    virtio_pci_ss.add(when: 'CONFIG_VHOST_USER_BLK', if_true: files('vhost-user-blk-pci.c'))
>>> +virtio_pci_ss.add(when: 'CONFIG_VHOST_VDPA_BLK', if_true: files('vhost-vdpa-blk-pci.c'))
>>>    virtio_pci_ss.add(when: 'CONFIG_VHOST_USER_INPUT', if_true: files('vhost-user-input-pci.c'))
>>>    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'))
>>> diff --git a/hw/virtio/vhost-vdpa-blk-pci.c b/hw/virtio/vhost-vdpa-blk-pci.c
>>> new file mode 100644
>>> index 0000000000..976c47fb4f
>>> --- /dev/null
>>> +++ b/hw/virtio/vhost-vdpa-blk-pci.c
>>> @@ -0,0 +1,101 @@
>>> +/*
>>> + * vhost-vdpa-blk PCI Bindings
>>> + *
>>> + * Copyright (C) 2021 Bytedance Inc. and/or its affiliates. All rights reserved.
>>> + *
>>> + * Author:
>>> + *   Xie Yongji <xieyongji@bytedance.com>
>>> + *
>>> + * This work is licensed under the terms of the GNU GPL, version 2.  See
>>> + * the COPYING 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-vdpa-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 "virtio-pci.h"
>>> +#include "qom/object.h"
>>> +
>>> +typedef struct VHostVdpaBlkPCI VHostVdpaBlkPCI;
>>> +
>>> +#define TYPE_VHOST_VDPA_BLK_PCI "vhost-vdpa-blk-pci-base"
>>> +DECLARE_INSTANCE_CHECKER(VHostVdpaBlkPCI, VHOST_VDPA_BLK_PCI,
>>> +                         TYPE_VHOST_VDPA_BLK_PCI)
>>> +
>>> +struct VHostVdpaBlkPCI {
>>> +    VirtIOPCIProxy parent_obj;
>>> +    VHostVdpaBlk vdev;
>>> +};
>>> +
>>> +static Property vhost_vdpa_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_vdpa_blk_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
>>> +{
>>> +    VHostVdpaBlkPCI *dev = VHOST_VDPA_BLK_PCI(vpci_dev);
>>> +    DeviceState *vdev = DEVICE(&dev->vdev);
>>> +    VHostBlkCommon *vbc = VHOST_BLK_COMMON(&dev->vdev);
>>> +
>>> +    if (vbc->num_queues == VHOST_BLK_AUTO_NUM_QUEUES) {
>>> +        vbc->num_queues = virtio_pci_optimal_num_queues(0);
>>> +    }
>>> +
>>> +    if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
>>> +        vpci_dev->nvectors = vbc->num_queues + 1;
>>> +    }
>>> +
>>> +    qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
>>> +}
>>> +
>>> +static void vhost_vdpa_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_vdpa_blk_pci_properties);
>>> +    k->realize = vhost_vdpa_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_vdpa_blk_pci_instance_init(Object *obj)
>>> +{
>>> +    VHostVdpaBlkPCI *dev = VHOST_VDPA_BLK_PCI(obj);
>>> +
>>> +    virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
>>> +                                TYPE_VHOST_VDPA_BLK);
>>> +    object_property_add_alias(obj, "bootindex", OBJECT(&dev->vdev),
>>> +                              "bootindex");
>>> +}
>>> +
>>> +static const VirtioPCIDeviceTypeInfo vhost_vdpa_blk_pci_info = {
>>> +    .base_name               = TYPE_VHOST_VDPA_BLK_PCI,
>>> +    .generic_name            = "vhost-vdpa-blk-pci",
>>> +    .transitional_name       = "vhost-vdpa-blk-pci-transitional",
>>> +    .non_transitional_name   = "vhost-vdpa-blk-pci-non-transitional",
>>> +    .instance_size  = sizeof(VHostVdpaBlkPCI),
>>> +    .instance_init  = vhost_vdpa_blk_pci_instance_init,
>>> +    .class_init     = vhost_vdpa_blk_pci_class_init,
>>> +};
>>> +
>>> +static void vhost_vdpa_blk_pci_register(void)
>>> +{
>>> +    virtio_pci_types_register(&vhost_vdpa_blk_pci_info);
>>> +}
>>
>> I wonder how could we use virtio-mmio for vDPA block here.
>>
> Use something like:
>
> -device vhost-vdpa-blk,vdpa-dev=/dev/vhost-vdpa-0 ?


Something like this, making vDPA indepedent for a specific bus is a 
great advantage.

Thanks


>
> Thanks,
> Yongji
>