All of lore.kernel.org
 help / color / mirror / Atom feed
From: longpeng2--- via <qemu-devel@nongnu.org>
To: Stefano Garzarella <sgarzare@redhat.com>
Cc: <stefanha@redhat.com>, <mst@redhat.com>, <jasowang@redhat.com>,
	<cohuck@redhat.com>, <pbonzini@redhat.com>,
	<arei.gonglei@huawei.com>, <yechuan@huawei.com>,
	<huangzhichao@huawei.com>, <qemu-devel@nongnu.org>
Subject: Re: [PATCH v5 3/4] vdpa: add vdpa-dev support
Date: Fri, 13 May 2022 10:17:41 +0800	[thread overview]
Message-ID: <a040df92-00f6-4e02-5a83-04b8c6ed5cef@huawei.com> (raw)
In-Reply-To: <20220512143601.dujcnth2rbrxgsbx@sgarzare-redhat>



在 2022/5/12 22:36, Stefano Garzarella 写道:
> On Thu, May 12, 2022 at 02:21:02PM +0800, Longpeng(Mike) wrote:
>> From: Longpeng <longpeng2@huawei.com>
>>
>> Supports vdpa-dev, we can use the deivce directly:
>>
>> -M microvm -m 512m -smp 2 -kernel ... -initrd ... -device \
>> vhost-vdpa-device,vhostdev=/dev/vhost-vdpa-x
>>
>> Signed-off-by: Longpeng <longpeng2@huawei.com>
>> ---
>> hw/virtio/Kconfig            |   5 +
>> hw/virtio/meson.build        |   1 +
>> hw/virtio/vdpa-dev.c         | 377 +++++++++++++++++++++++++++++++++++
>> include/hw/virtio/vdpa-dev.h |  43 ++++
>> 4 files changed, 426 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..724eb58a32 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
>> +    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..56597c881a
>> --- /dev/null
>> +++ b/hw/virtio/vdpa-dev.c
>> @@ -0,0 +1,377 @@
>> +/*
>> + * 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) {
>> +        error_setg(errp, "vhost-vdpa-device: vhostdev are missing");
>> +        return;
>> +    }
>> +
>> +    v->vhostfd = qemu_open(v->vhostdev, O_RDWR, errp);
>> +    if (*errp) {
>> +        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;
> 
> This goto seems wrong.
> 
> Either we use the `vhost_cleanup` label or we move this block just 
> before return as it seems to me was in v3.
>

Good catch. We should use 'vhost_cleanup' label here.

> Out of curiosity, is there a reason for this change from v3 or was a 
> simple mistake as a consequence of patch reorganization?
> 

We should invoke .post_init() before calling virtio_init() which would 
use the fields of VirtIOPCIProxy.

> Since I think v6 is needed, checkpatch has some warnings for exceeding 
> 80 characters, maybe some of them can be easily fixed.
> 

OK, I'll fix them.

> The rest LGTM, I think we are in a good shape :-)
> 
> Thanks,
> Stefano
> 
>> +    }
>> +
>> +    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_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
>>
> 
> .


  reply	other threads:[~2022-05-13  2:18 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-12  6:20 [PATCH v5 0/4] add generic vDPA device support Longpeng(Mike) via
2022-05-12  6:21 ` [PATCH v5 1/4] linux-headers: Update headers to Linux 5.18-rc6 Longpeng(Mike) via
2022-05-12  6:21 ` [PATCH v5 2/4] virtio: get class_id and pci device id by the virtio id Longpeng(Mike) via
2022-05-12  6:56   ` Michael S. Tsirkin
2022-05-13  3:17     ` longpeng2--- via
2022-05-12  6:21 ` [PATCH v5 3/4] vdpa: add vdpa-dev support Longpeng(Mike) via
2022-05-12 14:36   ` Stefano Garzarella
2022-05-13  2:17     ` longpeng2--- via [this message]
2022-05-13  6:34       ` Stefano Garzarella
2022-05-12  6:21 ` [PATCH v5 4/4] vdpa: add vdpa-dev-pci support Longpeng(Mike) via
2022-05-12 14:49   ` Stefano Garzarella

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=a040df92-00f6-4e02-5a83-04b8c6ed5cef@huawei.com \
    --to=qemu-devel@nongnu.org \
    --cc=arei.gonglei@huawei.com \
    --cc=cohuck@redhat.com \
    --cc=huangzhichao@huawei.com \
    --cc=jasowang@redhat.com \
    --cc=longpeng2@huawei.com \
    --cc=mst@redhat.com \
    --cc=pbonzini@redhat.com \
    --cc=sgarzare@redhat.com \
    --cc=stefanha@redhat.com \
    --cc=yechuan@huawei.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.