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=-13.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,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 3E1A6C63777 for ; Thu, 3 Dec 2020 06:50:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 990E320709 for ; Thu, 3 Dec 2020 06:50:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729718AbgLCGuO (ORCPT ); Thu, 3 Dec 2020 01:50:14 -0500 Received: from hqnvemgate25.nvidia.com ([216.228.121.64]:14066 "EHLO hqnvemgate25.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729114AbgLCGuO (ORCPT ); Thu, 3 Dec 2020 01:50:14 -0500 Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Wed, 02 Dec 2020 22:49:33 -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; Thu, 3 Dec 2020 06:49:32 +0000 Date: Thu, 3 Dec 2020 08:49:28 +0200 From: Eli Cohen To: "Michael S. Tsirkin" CC: Jason Wang , Cindy Lu , , Subject: Re: [PATCH] vdpa/mlx5: Use random MAC for the vdpa net instance Message-ID: <20201203064928.GA27404@mtl-vdi-166.wap.labs.mlnx> References: <20201130092759.GB99449@mtl-vdi-166.wap.labs.mlnx> <20201130043050-mutt-send-email-mst@kernel.org> <20201130103142-mutt-send-email-mst@kernel.org>

<20201202055714.GA224423@mtl-vdi-166.wap.labs.mlnx> <20201202041518-mutt-send-email-mst@kernel.org> <3e32ef6d-83c9-5866-30e5-f6eeacd5044d@redhat.com> <20201202165932-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: <20201202165932-mutt-send-email-mst@kernel.org> 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=1606978173; bh=rmEb5eJvsyJwIGz1fgWqF1+e7peJkGRDGkK7Rlu4wwY=; 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=WwOfoU9wXI4yXeZ9Pgo0RiiYXmkSf678T9q3G3u9cjHOHyEq9mNps9v1wDR0iEUOW tY7aeKQJvTaJFcBUSTaHE/2w+nCa0eWiVkLFxW1aA72+vW7xFzuJl9XQvs8T5cbcmw WEk5+M+biScOHPvzXuoE0kE8vcjtEeVF2UJ3DC8XZ9Ufpp1U96ZdWcbFjBKWjqJXt1 vES4M7HTPlUV3uYG5ZDpEHVV7DTVSc5I3Tz2GWBOcgHL2qM1Ewm+4bC2uLjFBlYQoa WGexA2+V3znoYfmP4OJWrXn819D86uuegeD056Mpas2V8lnll+RJ0E4E2CsXni8dss jnLiE8vrmvafg== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 02, 2020 at 05:00:22PM -0500, Michael S. Tsirkin wrote: > On Wed, Dec 02, 2020 at 09:48:25PM +0800, Jason Wang wrote: > >=20 > > On 2020/12/2 =E4=B8=8B=E5=8D=885:23, Michael S. Tsirkin wrote: > > > On Wed, Dec 02, 2020 at 07:57:14AM +0200, Eli Cohen wrote: > > > > On Wed, Dec 02, 2020 at 12:18:36PM +0800, Jason Wang wrote: > > > > > 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 wrote: > > > > > > > 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. Ts= irkin wrote: > > > > > > > > > > > On Mon, Nov 30, 2020 at 08:27:46AM +0200, Eli Cohen w= rote: > > > > > > > > > > > > On Sun, Nov 29, 2020 at 03:08:22PM -0500, Michael S= . Tsirkin wrote: > > > > > > > > > > > > > On Sun, Nov 29, 2020 at 08:43:51AM +0200, Eli Coh= en wrote: > > > > > > > > > > > > > > We should not try to use the VF MAC address as = that is used by the > > > > > > > > > > > > > > regular (e.g. mlx5_core) NIC implementation. In= stead, use a random > > > > > > > > > > > > > > generated MAC address. > > > > > > > > > > > > > >=20 > > > > > > > > > > > > > > Suggested by: Cindy Lu > > > > > > > > > > > > > > Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA drive= r for supported mlx5 devices") > > > > > > > > > > > > > > Signed-off-by: Eli Cohen > > > > > > > > > > > > > I didn't realise it's possible to use VF in two w= ays > > > > > > > > > > > > > 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 p= ossibly create > > > > > > > > > > > > several instances of vdpa net devices and nic net d= evices. > > > > > > > > > > > >=20 > > > > > > > > > > > > > Could you include a bit more description on the f= ailure > > > > > > > > > > > > > mode? > > > > > > > > > > > > Well, using the MAC address of the nic vport is wro= ng 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 problem? > > > > > > > > > > >=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= administering the > > > > > > > > > > > > NIC. This should invoke the set_config callbac= k. Unfortunately this > > > > > > > > > > > > is not implemented yet. > > > > > > > > > > > >=20 > > > > > > > > > > > > 2. Use a random MAC address. This is OK since if (1= ) is implemented it > > > > > > > > > > > > can always override this random configuration. > > > > > > > > > > > >=20 > > > > > > > > > > > > > It looks like changing a MAC could break some gue= sts, > > > > > > > > > > > > > can it not? > > > > > > > > > > > > >=20 > > > > > > > > > > > > No, it will not. The current version of mlx5 VDPA d= oes not allow regular > > > > > > > > > > > > NIC driver and VDPA to co-exist. I have patches rea= dy that enable that > > > > > > > > > > > > from steering point of view. I will post them here = once other patches on > > > > > > > > > > > > which they depend will be merged. > > > > > > > > > > > >=20 > > > > > > > > > > > > https://patchwork.ozlabs.org/project/netdev/patch/2= 0201120230339.651609-12-saeedm@nvidia.com/ > > > > > > > > > > > Could you be more explicit on the following points: > > > > > > > > > > > - which configuration is broken ATM (as in, two devic= e have identical > > > > > > > > > > > macs? any other issues)? > > > > > > > > > > The only wrong thing is the call to mlx5_query_nic_vpo= rt_mac_address(). > > > > > > > > > > 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 appropriat= e if it's a > > > > > > > > > dependency of a new feature. > > > > > > > > >=20 > > > > > > > > > > > - why won't device MAC change from guest point of vie= w? > > > > > > > > > > >=20 > > > > > > > > > > It's lack of implementation in qemu as far as I know. > > > > > > > > > Sorry not sure I understand. What's not implemented in QE= MU? > > > > > > > > >=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 traffic down. > > > > > > > Hmm the patch description says VF mac address, not 0 address.= Confused. > > > > > > > If there's no mac we can clear VIRTIO_NET_F_MAC and have gues= t > > > > > > > use a random value ... > > > > > I'm not sure this can work for all types of vDPA (e.g it could no= t be a > > > > > learning bridge in the swtich). > > > > >=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 overwr= ite the > > > > > > default address in VM, > > > > > 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 Otherwise 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 m= ac > > > > > > address with all 0--> > > > > > > qemu will not check this mac address and use it --> overwrite t= he mac > > > > > > address in qemu > > > > > >=20 > > > > > > So for my understanding there are several method to fix this pr= oblem > > > > > >=20 > > > > > > 1, qemu check the mac address, if the mac address is all 0, qem= u will > > > > > > ignore it and set the random mac address to mlx driver. > > > > > 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 did: > > > > 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 MA= C 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 c= an > > > > kidnap traffic that was not destined to it. > > > >=20 > > > > In addition, when VIRTIO_NET_F_MAC is published, attempts to change= the > > > > MAC address from the VM should result in error. > > > That is not what the spec says though. > > > VIRTIO_NET_F_MAC only says whether mac is valid in the config space. > > > Whether guest can control that depends on VIRTIO_NET_F_CTRL_MAC_ADDR: > > >=20 > > > The VIRTIO_NET_CTRL_MAC_ADDR_SET command is used to set the default = MAC address which rx > > > filtering accepts (and if VIRTIO_NET_F_MAC_ADDR has been negotiated,= this will be reflected in mac in > > > config space). > > > The command-specific-data for VIRTIO_NET_CTRL_MAC_ADDR_SET is the 6-= byte MAC address. > >=20 > >=20 > > Consider VIRTIO_NET_CTRL_MAC_ADDR_SET is not supported now. What Eli > > proposed here should work? > >=20 > > Thanks > >=20 >=20 > We can have management set a MAC address. Randomizing it in kernel > does not seem like a reasonable policy to me ... >=20 This manangement should be the VDPA tool that Parav is pushing. We can use it to set a MAC chosen by the user. The mlx5 vdpa driver can then use that MAC instead of randomizing a value. If no admin value is given we can use a random MAC. >=20 > > >=20 > > >=20 > > >=20 > > >=20 >=20