Re: [PATCH v2] hw/virtio/vhost-user: support obtain vdpa device's mac address automatically

[Jason Wang <jasowang@redhat.com>]

On Thu, Sep 22, 2022 at 1:58 AM Raphael Norwitz
<raphael.norwitz@nutanix.com> wrote:
>
> If I read your response on the other thread correctly, this change is intended
>
> to prioritize the MAC address exposed by DPDK over the one provided by the
>
> QEMU command line? Sounds reasonable in principle, but I would get confirmation
>
> from vDPA/vhost-net maintainers.

I think the best way is to (and it seems easier)

1) have the management layer to make sure the mac came from cli
matches the underlayer vDPA
2) having a sanity check and fail the device initialization if they don't match

Thanks

>
>
>
> That said the way you’re hacking the vhost-user code breaks a valuable check for
>
> bad vhost-user-blk backends. I would suggest finding another implementation which
>
> does not regress functionality for other device types.
>
>
>
>
>
> >From: Hao Chen <chenh@yusur.tech>
>
> >
>
> >When use dpdk-vdpa tests vdpa device. You need to specify the mac address to
>
> >start the virtual machine through libvirt or qemu, but now, the libvirt or
>
> >qemu can call dpdk vdpa vendor driver's ops .get_config through vhost_net_get_config
>
> >to get the mac address of the vdpa hardware without manual configuration.
>
> >
>
> >v1->v2:
>
> >Only copy ETH_ALEN data of netcfg for some vdpa device such as
>
> >NVIDIA BLUEFIELD DPU(BF2)'s netcfg->status is not right.
>
> >We only need the mac address and don't care about the status field.
>
> >
>
> >Signed-off-by: Hao Chen <chenh@yusur.tech>
>
> >---
>
> > hw/block/vhost-user-blk.c |  1 -
>
> > hw/net/virtio-net.c       |  7 +++++++
>
> > hw/virtio/vhost-user.c    | 19 -------------------
>
> > 3 files changed, 7 insertions(+), 20 deletions(-)
>
> >
>
> >diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
>
> >index 9117222456..5dca4eab09 100644
>
> >--- a/hw/block/vhost-user-blk.c
>
> >+++ b/hw/block/vhost-user-blk.c
>
> >@@ -337,7 +337,6 @@ static int vhost_user_blk_connect(DeviceState *dev, Error **errp)
>
> >
>
> >     vhost_dev_set_config_notifier(&s->dev, &blk_ops);
>
> >
>
> >-    s->vhost_user.supports_config = true;
>
> >     ret = vhost_dev_init(&s->dev, &s->vhost_user, VHOST_BACKEND_TYPE_USER, 0,
>
> >                          errp);
>
> >     if (ret < 0) {
>
> >diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
>
> >index dd0d056fde..90405083b1 100644
>
> >--- a/hw/net/virtio-net.c
>
> >+++ b/hw/net/virtio-net.c
>
> >@@ -166,6 +166,13 @@ static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config)
>
> >             }
>
> >             memcpy(config, &netcfg, n->config_size);
>
> >         }
>
> >+    } else if (nc->peer && nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_USER) {
>
> >+        ret = vhost_net_get_config(get_vhost_net(nc->peer), (uint8_t *)&netcfg,
>
> >+                                   n->config_size);
>
> >+        if (ret != -1) {
>
> >+               /* Automatically obtain the mac address of the vdpa device
>
> >+                * when using the dpdk vdpa */
>
> >+                memcpy(config, &netcfg, ETH_ALEN);
>
> >     }
>
> > }
>
> >
>
> >diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
>
> >index bd24741be8..8b01078249 100644
>
> >--- a/hw/virtio/vhost-user.c
>
> >+++ b/hw/virtio/vhost-user.c
>
> >@@ -2013,8 +2013,6 @@ static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque,
>
> >     }
>
> >
>
> >     if (virtio_has_feature(features, VHOST_USER_F_PROTOCOL_FEATURES)) {
>
> >-        bool supports_f_config = vus->supports_config ||
>
> >-            (dev->config_ops && dev->config_ops->vhost_dev_config_notifier);
>
> >         uint64_t protocol_features;
>
> >
>
> >         dev->backend_features |= 1ULL << VHOST_USER_F_PROTOCOL_FEATURES;
>
> >@@ -2033,23 +2031,6 @@ static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque,
>
> >          */
>
> >         protocol_features &= VHOST_USER_PROTOCOL_FEATURE_MASK;
>
> >
>
> >-        if (supports_f_config) {
>
> >-            if (!virtio_has_feature(protocol_features,
>
> >-                                    VHOST_USER_PROTOCOL_F_CONFIG)) {
>
> >-                error_setg(errp, "vhost-user device expecting "
>
> >-                           "VHOST_USER_PROTOCOL_F_CONFIG but the vhost-user backend does "
>
> >-                           "not support it.");
>
> >-                return -EPROTO;
>
> >-            }
>
> >-        } else {
>
> >-            if (virtio_has_feature(protocol_features,
>
> >-                                   VHOST_USER_PROTOCOL_F_CONFIG)) {
>
> >-                warn_reportf_err(*errp, "vhost-user backend supports "
>
> >-                                 "VHOST_USER_PROTOCOL_F_CONFIG but QEMU does not.");
>
> >-                protocol_features &= ~(1ULL << VHOST_USER_PROTOCOL_F_CONFIG);
>
> >-            }
>
> >-        }
>
> >-
>
> >         /* final set of protocol features */
>
> >         dev->protocol_features = protocol_features;
>
> >         err = vhost_user_set_protocol_features(dev, dev->protocol_features);
>
> >--
>
> >2.27.0
>
> >
>
>