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 6B7ABC63777 for ; Thu, 3 Dec 2020 12:10:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 056EA22203 for ; Thu, 3 Dec 2020 12:10:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388687AbgLCMKQ (ORCPT ); Thu, 3 Dec 2020 07:10:16 -0500 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:8075 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387983AbgLCMKP (ORCPT ); Thu, 3 Dec 2020 07:10:15 -0500 Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Thu, 03 Dec 2020 04:09:35 -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 12:09:33 +0000 Date: Thu, 3 Dec 2020 14:09:29 +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: <20201203120929.GA38007@mtl-vdi-166.wap.labs.mlnx> References: <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> <20201203064928.GA27404@mtl-vdi-166.wap.labs.mlnx> <20201203054330-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: <20201203054330-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=1606997375; bh=pVqN5SNT846fKrKSf6t+/xOvyhCYYlNVhd8b5CxCMAo=; 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=hpZBK7VfTsHmRNmL4oAl6UhRpQlzuOixtc/4KXcAef4iaFv5ldVqz4MJuNGWx95aW W74achJEB7QHxGoL/7djGuVMREZmOcTQFOhuVQIUkys5awhJOnWW/nRhcrIkrHTqzA ArHmVModb1Z61Abu0K18o/KLUPu6N7X8PuMlgLpuQHZpbX2ggyHxnkyFaySOqXMy74 IS7rH26Z0E/s7Ee0wXwgA0c2vp6miMvqvnmRh2Rtv9vOdsFTl25ZCjqq+nKVAYfMqK dOudw8ndD1Fg3Np5zMUL/jgr0i67nK08kq5ZCsrd8O3iZGGTEjqITDJGFuEhoq6fgy IBufh2XAEWp2w== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 03, 2020 at 05:44:17AM -0500, Michael S. Tsirkin wrote: > On Thu, Dec 03, 2020 at 08:49:28AM +0200, Eli Cohen wrote: > > 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 w= rote: > > > > > > > > > > > > On Mon, Nov 30, 2020 at 04:00:51AM -0500, Michael S= . Tsirkin wrote: > > > > > > > > > > > > > On Mon, Nov 30, 2020 at 08:27:46AM +0200, Eli Coh= en wrote: > > > > > > > > > > > > > > On Sun, Nov 29, 2020 at 03:08:22PM -0500, Micha= el S. Tsirkin 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, use a random > > > > > > > > > > > > > > > > generated MAC address. > > > > > > > > > > > > > > > >=20 > > > > > > > > > > > > > > > > Suggested by: Cindy Lu > > > > > > > > > > > > > > > > Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA d= river for supported mlx5 devices") > > > > > > > > > > > > > > > > Signed-off-by: Eli Cohen > > > > > > > > > > > > > > > I didn't realise it's possible to use VF in t= wo 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 c= an possibly create > > > > > > > > > > > > > > several instances of vdpa net devices and nic n= et devices. > > > > > > > > > > > > > >=20 > > > > > > > > > > > > > > > Could you include a bit more description on t= he 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_c= ore. > > > > > > > > > > > > > Right but ATM it doesn't coexist with vdpa so wha= t's the problem? > > > > > > > > > > > > >=20 > > > > > > > > > > > > This call is wrong: mlx5_query_nic_vport_mac_addre= ss() > > > > > > > > > > > >=20 > > > > > > > > > > > > > > > Is switching to a random mac for such an unus= ual > > > > > > > > > > > > > > > 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 cal= lback. Unfortunately this > > > > > > > > > > > > > > is not implemented yet. > > > > > > > > > > > > > >=20 > > > > > > > > > > > > > > 2. Use a random MAC address. This is OK since i= f (1) is implemented it > > > > > > > > > > > > > > can always override this random configurat= ion. > > > > > > > > > > > > > >=20 > > > > > > > > > > > > > > > It looks like changing a MAC could break some= guests, > > > > > > > > > > > > > > > can it not? > > > > > > > > > > > > > > >=20 > > > > > > > > > > > > > > No, it will not. The current version of mlx5 VD= PA 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 h= ere once other patches on > > > > > > > > > > > > > > which they depend will be merged. > > > > > > > > > > > > > >=20 > > > > > > > > > > > > > > https://patchwork.ozlabs.org/project/netdev/pat= ch/20201120230339.651609-12-saeedm@nvidia.com/ > > > > > > > > > > > > > Could you be more explicit on the following point= s: > > > > > > > > > > > > > - which configuration is broken ATM (as in, two d= evice have identical > > > > > > > > > > > > > macs? any other issues)? > > > > > > > > > > > > The only wrong thing is the call to mlx5_query_nic= _vport_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 approp= riate 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 kno= w. > > > > > > > > > > > Sorry not sure I understand. What's not implemented i= n QEMU? > > > > > > > > > > >=20 > > > > > > > > > > HI Michael, there are some bug in qemu to set_config, t= his will fix in future, > > > > > > > > > > But this patch is still needed, because without this pa= tch 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 addr= ess. Confused. > > > > > > > > > If there's no mac we can clear VIRTIO_NET_F_MAC and have = guest > > > > > > > > > use a random value ... > > > > > > > I'm not sure this can work for all types of vDPA (e.g it coul= d not 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 ov= erwrite 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(vde= v, > > > > > > > =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 --> overwri= te the mac > > > > > > > > address in qemu > > > > > > > >=20 > > > > > > > > So for my understanding there are several method to fix thi= s 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. > > > > > > > So my understanding is that, if mac address is all 0, vDPA pa= rent should not > > > > > > > advertise VIRTIO_NET_F_MAC. And qemu should emulate this feat= ure 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 th= e MAC can > > > > > > be either randomly generated value by mlx5_vdpa or by a managem= ent 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 a= nd can > > > > > > kidnap traffic that was not destined to it. > > > > > >=20 > > > > > > In addition, when VIRTIO_NET_F_MAC is published, attempts to ch= ange 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 spa= ce. > > > > > Whether guest can control that depends on VIRTIO_NET_F_CTRL_MAC_A= DDR: > > > > >=20 > > > > > The VIRTIO_NET_CTRL_MAC_ADDR_SET command is used to set the defa= ult MAC address which rx > > > > > filtering accepts (and if VIRTIO_NET_F_MAC_ADDR has been negotia= ted, this will be reflected in mac in > > > > > config space). > > > > > The command-specific-data for VIRTIO_NET_CTRL_MAC_ADDR_SET is th= e 6-byte MAC address. > > > >=20 > > > >=20 > > > > Consider VIRTIO_NET_CTRL_MAC_ADDR_SET is not supported now. What El= i > > > > 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 > >=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 > IIUC in this model devices are created by this tool, right? > Why not require the MAC when device is created? >=20 It is mentioned in Parav's patchset that this will be coming in a subsequent patch to his vdpa tool.=20 > > >=20 > > > > >=20 > > > > >=20 > > > > >=20 > > > > >=20 > > >=20 >=20