On Fri, Sep 23, 2022 at 11:36:38AM +0800, Jason Wang wrote:
> On Fri, Sep 23, 2022 at 11:33 AM 陈浩 <[email protected]> wrote:
> >
> >
> > On 2022/9/22 17:56, Michael S. Tsirkin wrote:
> > > On Thu, Sep 22, 2022 at 09:34:41AM +0800, Jason Wang wrote:
> > >> On Thu, Sep 22, 2022 at 1:58 AM Raphael Norwitz
> > >> <[email protected]> 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
> > > I think I agree, we should not overwrite user supplied arguments.
> > > I think the case where we might want to get the mac from VDPA
> > > and use it is when it's been assigned randomly as opposed to coming from 
> > > cli.
> > Yes, when the cli passes in a random mac address that is inconsistent
> > with the vdpa device, qemu still starts the virtual machine as usual,
> > but in this case, the qemu and vdpa environments do not work correctly.
> > So I want to get mac address directly from vdpa device instead of cli.
> 
> Let's teach the management to do that. It has a lot of advantages, more below.


No, making command line friendlier is a good idea.
the random address from cli is just that, random,
so why not take it from backend?


> Not sure for the DPDK case, but kernel vDPA allows the mgmt to
> provision the vDPA with a mac address which could be used in this
> case.
> 
> >
> > Having a sanity check and fail the device initialization if they don't
> > match is a good idea, but it seems more convenient to directly overwrite
> > the cli mac address.
> 
> This will confuse the management where it may do a lot of mac related setups.
> 
> Thanks

i do not think any management relies on the random mac hack.

> > >
> > >
> > >>>
> > >>>
> > >>> 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 <[email protected]>
> > >>>> 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 <[email protected]>
> > >>>> ---
> > >>>> 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
> > >>>
> > >
> >


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