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

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Sep 23, 2022 at 12:05:40PM +0800, Jason Wang wrote:
> On Fri, Sep 23, 2022 at 11:55 AM houyl@yusur.tech <houyl@yusur.tech> wrote:
> >
> > On Thu, 22 Sep 2022 09:34:41 +0800 Jason Wang<jasowang@redhat.com>  wrote:
> >
> >
> > >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
> >
> >  Agreed, that's no problem.

Actually, if we start failing here, won't it break working designs
in which vhost user does not really have a valid mac?

I am not sure we can start changing things so easily.
Let's add a protocol feature?


> > >2) having a sanity check and fail the device initialization if they don't match
> >
> > However, one MAC address for integrity check is from the cli, and the other MAC address is from the vDPA device,
> > How to get it?
> 
> VHOST_USER_GET_CONFIG?
> 
> Thanks
> 
> >
> > The current situation is if MAC came from cli don't match the underlayer vDPA, the virtual machine can still start without any hints.
> >
> > Thanks
> >
> >
> > >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
> > >>
> > >> >
> > >>
> > >>
> >