Re: [PATCH v4 3/4] vdpa: add vdpa-dev support

[Jason Wang]

On Tue, May 10, 2022 at 8:59 PM Longpeng(Mike) <longpeng2@huawei.com> wrote:
>
> From: Longpeng <longpeng2@huawei.com>
>
> Supports vdpa-dev.
>
> Signed-off-by: Longpeng <longpeng2@huawei.com>
> ---
>  hw/virtio/Kconfig            |   5 +
>  hw/virtio/meson.build        |   1 +
>  hw/virtio/vdpa-dev.c         | 385 +++++++++++++++++++++++++++++++++++
>  include/hw/virtio/vdpa-dev.h |  43 ++++
>  4 files changed, 434 insertions(+)
>  create mode 100644 hw/virtio/vdpa-dev.c
>  create mode 100644 include/hw/virtio/vdpa-dev.h
>
> diff --git a/hw/virtio/Kconfig b/hw/virtio/Kconfig
> index c144d42f9b..2723283382 100644
> --- a/hw/virtio/Kconfig
> +++ b/hw/virtio/Kconfig
> @@ -68,3 +68,8 @@ config VHOST_USER_RNG
>      bool
>      default y
>      depends on VIRTIO && VHOST_USER
> +
> +config VHOST_VDPA_DEV
> +    bool
> +    default y if VIRTIO_PCI

Do we have the plan to add VIRTIO_MMIO support?

> +    depends on VIRTIO && VHOST_VDPA && LINUX
> diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
> index 67dc77e00f..8f6f86db71 100644
> --- a/hw/virtio/meson.build
> +++ b/hw/virtio/meson.build
> @@ -29,6 +29,7 @@ virtio_ss.add(when: 'CONFIG_VHOST_USER_I2C', if_true: 
> files('vhost-user-i2c.c'))
>  virtio_ss.add(when: ['CONFIG_VIRTIO_PCI', 'CONFIG_VHOST_USER_I2C'], if_true: 
> files('vhost-user-i2c-pci.c'))
>  virtio_ss.add(when: 'CONFIG_VHOST_USER_RNG', if_true: 
> files('vhost-user-rng.c'))
>  virtio_ss.add(when: ['CONFIG_VHOST_USER_RNG', 'CONFIG_VIRTIO_PCI'], if_true: 
> files('vhost-user-rng-pci.c'))
> +virtio_ss.add(when: 'CONFIG_VHOST_VDPA_DEV', if_true: files('vdpa-dev.c'))
>
>  virtio_pci_ss = ss.source_set()
>  virtio_pci_ss.add(when: 'CONFIG_VHOST_VSOCK', if_true: 
> files('vhost-vsock-pci.c'))
> diff --git a/hw/virtio/vdpa-dev.c b/hw/virtio/vdpa-dev.c
> new file mode 100644
> index 0000000000..543b5b4b81
> --- /dev/null
> +++ b/hw/virtio/vdpa-dev.c
> @@ -0,0 +1,385 @@
> +/*
> + * Vhost Vdpa Device
> + *
> + * Copyright (c) Huawei Technologies Co., Ltd. 2022. All Rights Reserved.
> + *
> + * Authors:
> + *   Longpeng <longpeng2@huawei.com>
> + *
> + * Largely based on the "vhost-user-blk-pci.c" and "vhost-user-blk.c" 
> implemented by:
> + *   Changpeng Liu <changpeng.liu@intel.com>
> + *
> + * 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 <sys/ioctl.h>
> +#include <linux/vhost.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/virtio.h"
> +#include "hw/virtio/virtio-bus.h"
> +#include "hw/virtio/virtio-access.h"
> +#include "hw/virtio/vdpa-dev.h"
> +#include "sysemu/sysemu.h"
> +#include "sysemu/runstate.h"
> +
> +static void
> +vhost_vdpa_device_dummy_handle_output(VirtIODevice *vdev, VirtQueue *vq)
> +{
> +    /* Nothing to do */
> +}
> +
> +static uint32_t
> +vhost_vdpa_device_get_u32(int fd, unsigned long int cmd, Error **errp)
> +{
> +    uint32_t val = (uint32_t)-1;
> +
> +    if (ioctl(fd, cmd, &val) < 0) {
> +        error_setg(errp, "vhost-vdpa-device: cmd 0x%lx failed: %s",
> +                   cmd, strerror(errno));
> +    }
> +
> +    return val;
> +}
> +
> +static void vhost_vdpa_device_realize(DeviceState *dev, Error **errp)
> +{
> +    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> +    VhostVdpaDevice *v = VHOST_VDPA_DEVICE(vdev);
> +    uint16_t max_queue_size;
> +    struct vhost_virtqueue *vqs;
> +    int i, ret;
> +
> +    if (!v->vhostdev && v->vhostfd == -1) {
> +        error_setg(errp, "both vhostdev and vhostfd are missing");
> +        return;
> +    }
> +
> +    if (v->vhostdev && v->vhostfd != -1) {
> +        error_setg(errp, "both vhostdev and vhostfd are set");
> +        return;
> +    }
> +
> +    if (v->vhostfd == -1) {
> +        v->vhostfd = qemu_open(v->vhostdev, O_RDWR, errp);
> +        if (*errp) {

Is this better to set error messages for all the possible failures
during realization?

> +            return;
> +        }
> +    }
> +    v->vdpa.device_fd = v->vhostfd;
> +
> +    v->vdev_id = vhost_vdpa_device_get_u32(v->vhostfd,
> +                                           VHOST_VDPA_GET_DEVICE_ID, errp);
> +    if (*errp) {
> +        goto out;
> +    }
> +
> +    max_queue_size = vhost_vdpa_device_get_u32(v->vhostfd,
> +                                               VHOST_VDPA_GET_VRING_NUM, 
> errp);
> +    if (*errp) {
> +        goto out;
> +    }
> +
> +    if (v->queue_size > max_queue_size) {
> +        error_setg(errp, "vhost-vdpa-device: invalid queue_size: %u 
> (max:%u)",
> +                   v->queue_size, max_queue_size);
> +        goto out;
> +    } else if (!v->queue_size) {
> +        v->queue_size = max_queue_size;
> +    }
> +
> +    v->num_queues = vhost_vdpa_device_get_u32(v->vhostfd,
> +                                              VHOST_VDPA_GET_VQS_COUNT, 
> errp);
> +    if (*errp) {
> +        goto out;
> +    }
> +
> +    if (!v->num_queues || v->num_queues > VIRTIO_QUEUE_MAX) {
> +        error_setg(errp, "invalid number of virtqueues: %u (max:%u)",
> +                   v->num_queues, VIRTIO_QUEUE_MAX);
> +        goto out;
> +    }
> +
> +    v->dev.nvqs = v->num_queues;
> +    vqs = g_new0(struct vhost_virtqueue, v->dev.nvqs);
> +    v->dev.vqs = vqs;
> +    v->dev.vq_index = 0;
> +    v->dev.vq_index_end = v->dev.nvqs;
> +    v->dev.backend_features = 0;
> +    v->started = false;
> +
> +    ret = vhost_dev_init(&v->dev, &v->vdpa, VHOST_BACKEND_TYPE_VDPA, 0, 
> NULL);
> +    if (ret < 0) {
> +        error_setg(errp, "vhost-vdpa-device: vhost initialization failed: 
> %s",
> +                   strerror(-ret));
> +        goto free_vqs;
> +    }
> +
> +    v->config_size = vhost_vdpa_device_get_u32(v->vhostfd,
> +                                               VHOST_VDPA_GET_CONFIG_SIZE, 
> errp);
> +    if (*errp) {
> +        goto vhost_cleanup;
> +    }
> +
> +    if (v->post_init && v->post_init(v, errp) < 0) {
> +        goto free_virtio;
> +    }
> +
> +    v->config = g_malloc0(v->config_size);
> +
> +    ret = vhost_dev_get_config(&v->dev, v->config, v->config_size, NULL);
> +    if (ret < 0) {
> +        error_setg(errp, "vhost-vdpa-device: get config failed");
> +        goto free_config;
> +    }
> +
> +    virtio_init(vdev, "vhost-vdpa", v->vdev_id, v->config_size);
> +
> +    v->virtqs = g_new0(VirtQueue *, v->dev.nvqs);
> +    for (i = 0; i < v->dev.nvqs; i++) {
> +        v->virtqs[i] = virtio_add_queue(vdev, v->queue_size,
> +                                        
> vhost_vdpa_device_dummy_handle_output);
> +    }
> +
> +    return;
> +
> +free_virtio:
> +    for (i = 0; i < v->num_queues; i++) {
> +        virtio_delete_queue(v->virtqs[i]);
> +    }
> +    g_free(v->virtqs);
> +    virtio_cleanup(vdev);
> +free_config:
> +    g_free(v->config);
> +vhost_cleanup:
> +    vhost_dev_cleanup(&v->dev);
> +free_vqs:
> +    g_free(vqs);
> +out:
> +    qemu_close(v->vhostfd);
> +    v->vhostfd = -1;
> +}
> +
> +static void vhost_vdpa_device_unrealize(DeviceState *dev)
> +{
> +    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> +    VhostVdpaDevice *s = VHOST_VDPA_DEVICE(vdev);
> +    int i;
> +
> +    virtio_set_status(vdev, 0);
> +
> +    for (i = 0; i < s->num_queues; i++) {
> +        virtio_delete_queue(s->virtqs[i]);
> +    }
> +    g_free(s->virtqs);
> +    virtio_cleanup(vdev);
> +
> +    g_free(s->config);
> +    g_free(s->dev.vqs);
> +    vhost_dev_cleanup(&s->dev);
> +    qemu_close(s->vhostfd);
> +    s->vhostfd = -1;
> +}
> +
> +static void
> +vhost_vdpa_device_get_config(VirtIODevice *vdev, uint8_t *config)
> +{
> +    VhostVdpaDevice *s = VHOST_VDPA_DEVICE(vdev);
> +
> +    memcpy(config, s->config, s->config_size);
> +}
> +
> +static void
> +vhost_vdpa_device_set_config(VirtIODevice *vdev, const uint8_t *config)
> +{
> +    VhostVdpaDevice *s = VHOST_VDPA_DEVICE(vdev);
> +    int ret;
> +
> +    ret = vhost_dev_set_config(&s->dev, s->config, 0, s->config_size,
> +                               VHOST_SET_CONFIG_TYPE_MASTER);
> +    if (ret) {
> +        error_report("set device config space failed");
> +        return;
> +    }
> +}
> +
> +static uint64_t vhost_vdpa_device_get_features(VirtIODevice *vdev,
> +                                               uint64_t features,
> +                                               Error **errp)
> +{
> +    VhostVdpaDevice *s = VHOST_VDPA_DEVICE(vdev);
> +    uint64_t backend_features = s->dev.features;
> +
> +    if (!virtio_has_feature(features, VIRTIO_F_IOMMU_PLATFORM)) {
> +        virtio_clear_feature(&backend_features, VIRTIO_F_IOMMU_PLATFORM);
> +    }
> +
> +    return backend_features;
> +}
> +
> +static int vhost_vdpa_device_start(VirtIODevice *vdev, Error **errp)
> +{
> +    VhostVdpaDevice *s = VHOST_VDPA_DEVICE(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_setg(errp, "binding does not support guest notifiers");
> +        return -ENOSYS;
> +    }
> +
> +    ret = vhost_dev_enable_notifiers(&s->dev, vdev);
> +    if (ret < 0) {
> +        error_setg_errno(errp, -ret, "Error enabling host notifiers");
> +        return ret;
> +    }
> +
> +    ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, true);
> +    if (ret < 0) {
> +        error_setg_errno(errp, -ret, "Error binding guest notifier");
> +        goto err_host_notifiers;
> +    }
> +
> +    s->dev.acked_features = vdev->guest_features;
> +
> +    ret = vhost_dev_start(&s->dev, vdev);
> +    if (ret < 0) {
> +        error_setg_errno(errp, -ret, "Error starting vhost");
> +        goto err_guest_notifiers;
> +    }
> +    s->started = true;
> +
> +    /*
> +     * 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 ret;
> +
> +err_guest_notifiers:
> +    k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
> +err_host_notifiers:
> +    vhost_dev_disable_notifiers(&s->dev, vdev);
> +    return ret;
> +}
> +
> +static void vhost_vdpa_device_stop(VirtIODevice *vdev)
> +{
> +    VhostVdpaDevice *s = VHOST_VDPA_DEVICE(vdev);
> +    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> +    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> +    int ret;
> +
> +    if (!s->started) {
> +        return;
> +    }
> +    s->started = false;
> +
> +    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_vdpa_device_set_status(VirtIODevice *vdev, uint8_t status)
> +{
> +    VhostVdpaDevice *s = VHOST_VDPA_DEVICE(vdev);
> +    bool should_start = virtio_device_started(vdev, status);
> +    Error *local_err = NULL;
> +    int ret;
> +
> +    if (!vdev->vm_running) {
> +        should_start = false;
> +    }
> +
> +    if (s->started == should_start) {
> +        return;
> +    }
> +
> +    if (should_start) {
> +        ret = vhost_vdpa_device_start(vdev, &local_err);
> +        if (ret < 0) {
> +            error_reportf_err(local_err, "vhost-vdpa-device: start failed: 
> ");
> +        }
> +    } else {
> +        vhost_vdpa_device_stop(vdev);
> +    }
> +}
> +
> +static Property vhost_vdpa_device_properties[] = {
> +    DEFINE_PROP_STRING("vhostdev", VhostVdpaDevice, vhostdev),
> +    DEFINE_PROP_INT32("vhostfd", VhostVdpaDevice, vhostfd, -1),

This is probably not needed since we can "abuse" /dev/fd/X for vhostdev.

Thanks

> +    DEFINE_PROP_UINT16("queue-size", VhostVdpaDevice, queue_size, 0),
> +    DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static const VMStateDescription vmstate_vhost_vdpa_device = {
> +    .name = "vhost-vdpa-device",
> +    .unmigratable = 1,
> +    .minimum_version_id = 1,
> +    .version_id = 1,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_VIRTIO_DEVICE,
> +        VMSTATE_END_OF_LIST()
> +    },
> +};
> +
> +static void vhost_vdpa_device_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
> +
> +    device_class_set_props(dc, vhost_vdpa_device_properties);
> +    dc->desc = "VDPA-based generic device assignment";
> +    dc->vmsd = &vmstate_vhost_vdpa_device;
> +    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
> +    vdc->realize = vhost_vdpa_device_realize;
> +    vdc->unrealize = vhost_vdpa_device_unrealize;
> +    vdc->get_config = vhost_vdpa_device_get_config;
> +    vdc->set_config = vhost_vdpa_device_set_config;
> +    vdc->get_features = vhost_vdpa_device_get_features;
> +    vdc->set_status = vhost_vdpa_device_set_status;
> +}
> +
> +static void vhost_vdpa_device_instance_init(Object *obj)
> +{
> +    VhostVdpaDevice *s = VHOST_VDPA_DEVICE(obj);
> +
> +    device_add_bootindex_property(obj, &s->bootindex, "bootindex",
> +                                  NULL, DEVICE(obj));
> +}
> +
> +static const TypeInfo vhost_vdpa_device_info = {
> +    .name = TYPE_VHOST_VDPA_DEVICE,
> +    .parent = TYPE_VIRTIO_DEVICE,
> +    .instance_size = sizeof(VhostVdpaDevice),
> +    .class_init = vhost_vdpa_device_class_init,
> +    .instance_init = vhost_vdpa_device_instance_init,
> +};
> +
> +static void register_vhost_vdpa_device_type(void)
> +{
> +    type_register_static(&vhost_vdpa_device_info);
> +}
> +
> +type_init(register_vhost_vdpa_device_type);
> diff --git a/include/hw/virtio/vdpa-dev.h b/include/hw/virtio/vdpa-dev.h
> new file mode 100644
> index 0000000000..4dbf98195c
> --- /dev/null
> +++ b/include/hw/virtio/vdpa-dev.h
> @@ -0,0 +1,43 @@
> +/*
> + * Vhost Vdpa Device
> + *
> + * Copyright (c) Huawei Technologies Co., Ltd. 2022. All Rights Reserved.
> + *
> + * Authors:
> + *   Longpeng <longpeng2@huawei.com>
> + *
> + * Largely based on the "vhost-user-blk.h" implemented by:
> + *   Changpeng Liu <changpeng.liu@intel.com>
> + *
> + * 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_VDPA_DEVICE_H
> +#define _VHOST_VDPA_DEVICE_H
> +
> +#include "hw/virtio/vhost.h"
> +#include "hw/virtio/vhost-vdpa.h"
> +#include "qom/object.h"
> +
> +
> +#define TYPE_VHOST_VDPA_DEVICE "vhost-vdpa-device"
> +OBJECT_DECLARE_SIMPLE_TYPE(VhostVdpaDevice, VHOST_VDPA_DEVICE)
> +
> +struct VhostVdpaDevice {
> +    VirtIODevice parent_obj;
> +    char *vhostdev;
> +    int vhostfd;
> +    int32_t bootindex;
> +    uint32_t vdev_id;
> +    uint32_t num_queues;
> +    struct vhost_dev dev;
> +    struct vhost_vdpa vdpa;
> +    VirtQueue **virtqs;
> +    uint8_t *config;
> +    int config_size;
> +    uint16_t queue_size;
> +    bool started;
> +    int (*post_init)(VhostVdpaDevice *v, Error **errp);
> +};
> +
> +#endif
> --
> 2.23.0
>