From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 773F9C64E7C for ; Wed, 2 Dec 2020 05:58:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0F994221FE for ; Wed, 2 Dec 2020 05:58:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728504AbgLBF6B (ORCPT ); Wed, 2 Dec 2020 00:58:01 -0500 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:18567 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726981AbgLBF6A (ORCPT ); Wed, 2 Dec 2020 00:58:00 -0500 Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Tue, 01 Dec 2020 21:57:20 -0800 Received: from mtl-vdi-166.wap.labs.mlnx (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 2 Dec 2020 05:57:18 +0000 Date: Wed, 2 Dec 2020 07:57:14 +0200 From: Eli Cohen To: Jason Wang CC: Cindy Lu , "Michael S. Tsirkin" , , Subject: Re: [PATCH] vdpa/mlx5: Use random MAC for the vdpa net instance Message-ID: <20201202055714.GA224423@mtl-vdi-166.wap.labs.mlnx> References: <20201129064351.63618-1-elic@nvidia.com> <20201129150505-mutt-send-email-mst@kernel.org> <20201130062746.GA99449@mtl-vdi-166.wap.labs.mlnx> <20201130035147-mutt-send-email-mst@kernel.org> <20201130092759.GB99449@mtl-vdi-166.wap.labs.mlnx> <20201130043050-mutt-send-email-mst@kernel.org> <20201130103142-mutt-send-email-mst@kernel.org>

MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: User-Agent: Mutt/1.9.5 (bf161cf53efb) (2018-04-13) X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL105.nvidia.com (172.20.187.12) To HQMAIL107.nvidia.com (172.20.187.13) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1606888640; bh=S/I3nyXsabZgTsPwG212nfh812Q6Bj5OdbYCvgzL54o=; h=Date:From:To:CC:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:Content-Transfer-Encoding: In-Reply-To:User-Agent:X-Originating-IP:X-ClientProxiedBy; b=IcRYpFi0stHxwtxOoFzrz2nS8c7zYT3qWwdUZzLndGhVgBEhudWzgRzbdSS7R80Op 5rKPpBxWuXKIlo1k476iOPCKMafGx68/tROiwfZyLfwdpU/AHFvi6J3fLIGIrGhTGR CM9hfvP8q28tijfckW+31D48CW49oe7K45M6niwTNmcXYM5flFNsSNxt54+Un8nQ/T iyaAk7s9/9niah+fAsCIpaE7nheVxy54CnHhjlWOA58xFlGHOjuxIjyn2HVJ3ZqANe 7/yjFvgoPDJTBUl+6+sFz8sqN32C4J0aEYuv9p1WZmwdIH5veJfXHoHE3HDSgm7BfZ JON0eu//OpoDw== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 02, 2020 at 12:18:36PM +0800, Jason Wang wrote: >=20 > On 2020/12/1 =E4=B8=8B=E5=8D=885:23, Cindy Lu wrote: > > On Mon, Nov 30, 2020 at 11:33 PM Michael S. Tsirkin wr= ote: > > > On Mon, Nov 30, 2020 at 06:41:45PM +0800, Cindy Lu wrote: > > > > On Mon, Nov 30, 2020 at 5:33 PM Michael S. Tsirkin = wrote: > > > > > On Mon, Nov 30, 2020 at 11:27:59AM +0200, Eli Cohen wrote: > > > > > > On Mon, Nov 30, 2020 at 04:00:51AM -0500, Michael S. Tsirkin wr= ote: > > > > > > > On Mon, Nov 30, 2020 at 08:27:46AM +0200, Eli Cohen wrote: > > > > > > > > On Sun, Nov 29, 2020 at 03:08:22PM -0500, Michael S. Tsirki= n wrote: > > > > > > > > > On Sun, Nov 29, 2020 at 08:43:51AM +0200, Eli Cohen wrote= : > > > > > > > > > > We should not try to use the VF MAC address as that is = used by the > > > > > > > > > > regular (e.g. mlx5_core) NIC implementation. Instead, u= se a random > > > > > > > > > > generated MAC address. > > > > > > > > > >=20 > > > > > > > > > > Suggested by: Cindy Lu > > > > > > > > > > Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for su= pported mlx5 devices") > > > > > > > > > > Signed-off-by: Eli Cohen > > > > > > > > > I didn't realise it's possible to use VF in two ways > > > > > > > > > with and without vdpa. > > > > > > > > Using a VF you can create quite a few resources, e.g. send = queues > > > > > > > > recieve queues, virtio_net queues etc. So you can possibly = create > > > > > > > > several instances of vdpa net devices and nic net devices. > > > > > > > >=20 > > > > > > > > > Could you include a bit more description on the failure > > > > > > > > > mode? > > > > > > > > Well, using the MAC address of the nic vport is wrong since= that is the > > > > > > > > MAC of the regular NIC implementation of mlx5_core. > > > > > > > Right but ATM it doesn't coexist with vdpa so what's the prob= lem? > > > > > > >=20 > > > > > > This call is wrong: mlx5_query_nic_vport_mac_address() > > > > > >=20 > > > > > > > > > Is switching to a random mac for such an unusual > > > > > > > > > configuration really justified? > > > > > > > > Since I can't use the NIC's MAC address, I have two options= : > > > > > > > > 1. To get the MAC address as was chosen by the user adminis= tering the > > > > > > > > NIC. This should invoke the set_config callback. Unfort= unately this > > > > > > > > is not implemented yet. > > > > > > > >=20 > > > > > > > > 2. Use a random MAC address. This is OK since if (1) is imp= lemented it > > > > > > > > can always override this random configuration. > > > > > > > >=20 > > > > > > > > > It looks like changing a MAC could break some guests, > > > > > > > > > can it not? > > > > > > > > >=20 > > > > > > > > No, it will not. The current version of mlx5 VDPA does not = allow regular > > > > > > > > NIC driver and VDPA to co-exist. I have patches ready that = enable that > > > > > > > > from steering point of view. I will post them here once oth= er patches on > > > > > > > > which they depend will be merged. > > > > > > > >=20 > > > > > > > > https://patchwork.ozlabs.org/project/netdev/patch/202011202= 30339.651609-12-saeedm@nvidia.com/ > > > > > > > Could you be more explicit on the following points: > > > > > > > - which configuration is broken ATM (as in, two device have i= dentical > > > > > > > macs? any other issues)? > > > > > > The only wrong thing is the call to mlx5_query_nic_vport_mac_a= ddress(). > > > > > > It's not breaking anything yet is wrong. The random MAC address= setting > > > > > > is required for the steering patches. > > > > > Okay so I'm not sure the Fixes tag at least is appropriate if it'= s a > > > > > dependency of a new feature. > > > > >=20 > > > > > > > - why won't device MAC change from guest point of view? > > > > > > >=20 > > > > > > It's lack of implementation in qemu as far as I know. > > > > > Sorry not sure I understand. What's not implemented in QEMU? > > > > >=20 > > > > HI Michael, there are some bug in qemu to set_config, this will fix= in future, > > > > But this patch is still needed, because without this patch the mlx > > > > driver will give an 0 mac address to qemu > > > > and qemu will overwrite the default mac address. This will cause t= raffic down. > > > Hmm the patch description says VF mac address, not 0 address. Confuse= d. > > > If there's no mac we can clear VIRTIO_NET_F_MAC and have guest > > > use a random value ... >=20 >=20 > I'm not sure this can work for all types of vDPA (e.g it could not be a > learning bridge in the swtich). >=20 >=20 > > >=20 > > hi Michael=EF=BC=8C > > I have tried as your suggestion, seems even remove the > > VIRTIO_NET_F_MAC the qemu will still call get_cinfig and overwrite the > > default address in VM, >=20 >=20 > This looks a bug in qemu, in guest driver we had: >=20 > =C2=A0=C2=A0=C2=A0 /* Configuration may specify what MAC to use.=C2=A0 Ot= herwise random. */ > =C2=A0=C2=A0=C2=A0 if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) > =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 virtio_cread_bytes(vdev, > =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2= =A0 =C2=A0=C2=A0 offsetof(struct virtio_net_config, mac), > =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2= =A0 =C2=A0=C2=A0 dev->dev_addr, dev->addr_len); > =C2=A0=C2=A0=C2=A0 else > =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 eth_hw_addr_random(dev); >=20 >=20 > > this process is like > > vdpa _init -->qemu call get_config ->mlx driver will give an mac > > address with all 0--> > > qemu will not check this mac address and use it --> overwrite the mac > > address in qemu > >=20 > > So for my understanding there are several method to fix this problem > >=20 > > 1, qemu check the mac address, if the mac address is all 0, qemu will > > ignore it and set the random mac address to mlx driver. >=20 >=20 > So my understanding is that, if mac address is all 0, vDPA parent should = not > advertise VIRTIO_NET_F_MAC. And qemu should emulate this feature as you d= id: Thinking it over, at least in mlx5, I should always advertise VIRTIO_NET_F_MAC and set a non zero MAC value. The source of the MAC can be either randomly generated value by mlx5_vdpa or by a management tool. This is important becauase we should not let the VM modify the MAC. If we do it can set a MAC value identical to the mlx5 NIC driver and can kidnap traffic that was not destined to it. In addition, when VIRTIO_NET_F_MAC is published, attempts to change the MAC address from the VM should result in error. >=20 > 1) get a random mac > 2) advertise VIRTIO_NET_F_MAC > 3) set the random mac to vDPA through set_config > 4) advertise the random mac to emulated config to guest >=20 >=20 > > 2. mlx driver checks the mac address and if this mac is 0, return fail > > to qemu, but this need to change the UAPI. >=20 >=20 > uAPI is probably fine since ioctl can fail.=C2=A0 We can change the to al= low the > set_config to fail but virito spec doesn't have a way to advertise the er= ror > in this case. Anyway, the driver only risk itself for setting a wrong val= ue, > so we're probably fine. >=20 > Thanks >=20 >=20 > > 3. mlx driver it shelf should get an correct mac address while it init. > > 4. add check in qemu get_config function , if there is not F_MAC Then > > ignore the mac address from mlx driver > >=20 > > not sure which method is more suitable ? > >=20 > > Thanks > > Cindy > >=20 > >=20 > >=20 > > > > > > > > > > --- > > > > > > > > > > drivers/vdpa/mlx5/net/mlx5_vnet.c | 5 +---- > > > > > > > > > > 1 file changed, 1 insertion(+), 4 deletions(-) > > > > > > > > > >=20 > > > > > > > > > > diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/driver= s/vdpa/mlx5/net/mlx5_vnet.c > > > > > > > > > > index 1fa6fcac8299..80d06d958b8b 100644 > > > > > > > > > > --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c > > > > > > > > > > +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c > > > > > > > > > > @@ -1955,10 +1955,7 @@ void *mlx5_vdpa_add_dev(struct m= lx5_core_dev *mdev) > > > > > > > > > > if (err) > > > > > > > > > > goto err_mtu; > > > > > > > > > >=20 > > > > > > > > > > - err =3D mlx5_query_nic_vport_mac_address(mdev, 0,= 0, config->mac); > > > > > > > > > > - if (err) > > > > > > > > > > - goto err_mtu; > > > > > > > > > > - > > > > > > > > > > + eth_random_addr(config->mac); > > > > > > > > > > mvdev->vdev.dma_dev =3D mdev->device; > > > > > > > > > > err =3D mlx5_vdpa_alloc_resources(&ndev->mvdev); > > > > > > > > > > if (err) > > > > > > > > > > -- > > > > > > > > > > 2.26.2 >=20