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=-12.2 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 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 CCCAEC64E8A for ; Thu, 3 Dec 2020 12:17:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5F4C920663 for ; Thu, 3 Dec 2020 12:17:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730349AbgLCMRO (ORCPT ); Thu, 3 Dec 2020 07:17:14 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:23508 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726148AbgLCMRN (ORCPT ); Thu, 3 Dec 2020 07:17:13 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1606997745; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Dv989P1CZtRRl41OCLQYNKxYCvCFS0Q8rKdLF2QSMic=; b=bpY6vC4B3MfGZ73tytJAlBjS/x/8x/mxr8EmrPy9gL/9kiw216F3/2PPxNKS6popfdkfXp CVfD8g12hvhrMsae2zoQQdfpecZsWtxcbXq0i4a++omzr0tXokC3zeFRPGRWsRoyqyTAow /VTvVavLCzjb9HtQ1rjmeu8BQGiZ5xI= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-281-FRhzakcSMY65FDYtDDEvhQ-1; Thu, 03 Dec 2020 07:15:42 -0500 X-MC-Unique: FRhzakcSMY65FDYtDDEvhQ-1 Received: by mail-wr1-f72.google.com with SMTP id p18so1156171wro.9 for ; Thu, 03 Dec 2020 04:15:42 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=Dv989P1CZtRRl41OCLQYNKxYCvCFS0Q8rKdLF2QSMic=; b=BCU5jIi02PD7/JpgdqcyrQOV4nVFepMCBAkEtlDw8JcYRchvs10xJKqlya4KQAGbLA HGJzSvUl7e7upSqbyhS6tBOihGzVFKiGM8s0kEL/VqEQ7DrSh5+btAcECQF4Fal40s0v cXVWGun3FzT63YpUEYMaur9KOwojODxVQVqC9g9DbZyqDBhsLQ+hVAvbSJINkQBmJLv0 zi82tiE+yZjAWhGgYLSLxq+6ROJVIWUOM4fuj/+0A/OsU2dc9qQLrpMqtiEvnSKeq1NZ i8xE3KBBpfNTh8oTwQwmr3A/jDQOGKLd7RC3Kh4uEsppdf1TkxHDcggbBuxsxY6C11Mo EdFQ== X-Gm-Message-State: AOAM530CSNHcWqiRfrPL76nPPquhI2vh2R93/CGLmvI4L9/hkVh00Ags GrUsvUpJF3RjZGTTMG1jVlU2FHGBdtZMAoWaP7bvyscau9WrfaZl6LI4wsyOKbO6+CRvitnQaRG sYSA2StwGJArKLNOQCrN+IPJj X-Received: by 2002:a1c:810c:: with SMTP id c12mr3086994wmd.96.1606997741059; Thu, 03 Dec 2020 04:15:41 -0800 (PST) X-Google-Smtp-Source: ABdhPJza8hZZny/iCFLZbf13T7T+/P5rfHVgXHh/cSBZIhWZH/GIMCPPSCrnXcxv5ZGQg4++jJf31Q== X-Received: by 2002:a1c:810c:: with SMTP id c12mr3086964wmd.96.1606997740737; Thu, 03 Dec 2020 04:15:40 -0800 (PST) Received: from redhat.com (bzq-79-176-44-197.red.bezeqint.net. [79.176.44.197]) by smtp.gmail.com with ESMTPSA id t184sm1377556wmt.13.2020.12.03.04.15.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Dec 2020 04:15:39 -0800 (PST) Date: Thu, 3 Dec 2020 07:15:37 -0500 From: "Michael S. Tsirkin" To: Eli Cohen Cc: Jason Wang , Cindy Lu , virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] vdpa/mlx5: Use random MAC for the vdpa net instance Message-ID: <20201203071414-mutt-send-email-mst@kernel.org> 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> <20201203120929.GA38007@mtl-vdi-166.wap.labs.mlnx> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20201203120929.GA38007@mtl-vdi-166.wap.labs.mlnx> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 03, 2020 at 02:09:29PM +0200, Eli Cohen wrote: > 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: > > > > > > > > > > On 2020/12/2 下午5:23, 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 下午5:23, 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. Tsirkin wrote: > > > > > > > > > > > > > > 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. 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. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Suggested by: Cindy Lu > > > > > > > > > > > > > > > > > Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported 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. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 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 problem? > > > > > > > > > > > > > > > > > > > > > > > > > > > This call is wrong: mlx5_query_nic_vport_mac_address() > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 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 callback. Unfortunately this > > > > > > > > > > > > > > > is not implemented yet. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 2. Use a random MAC address. This is OK since if (1) is implemented it > > > > > > > > > > > > > > > can always override this random configuration. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > It looks like changing a MAC could break some guests, > > > > > > > > > > > > > > > > can it not? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 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 other patches on > > > > > > > > > > > > > > > which they depend will be merged. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > https://patchwork.ozlabs.org/project/netdev/patch/20201120230339.651609-12-saeedm@nvidia.com/ > > > > > > > > > > > > > > Could you be more explicit on the following points: > > > > > > > > > > > > > > - which configuration is broken ATM (as in, two device 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 appropriate if it's a > > > > > > > > > > > > dependency of a new feature. > > > > > > > > > > > > > > > > > > > > > > > > > > - why won't device MAC change from guest point of view? > > > > > > > > > > > > > > > > > > > > > > > > > > > It's lack of implementation in qemu as far as I know. > > > > > > > > > > > > Sorry not sure I understand. What's not implemented in QEMU? > > > > > > > > > > > > > > > > > > > > > > > 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 guest > > > > > > > > > > use a random value ... > > > > > > > > I'm not sure this can work for all types of vDPA (e.g it could not be a > > > > > > > > learning bridge in the swtich). > > > > > > > > > > > > > > > > > > > > > > > > > hi Michael， > > > > > > > > > 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, > > > > > > > > This looks a bug in qemu, in guest driver we had: > > > > > > > > > > > > > > > >     /* Configuration may specify what MAC to use.  Otherwise random. */ > > > > > > > >     if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) > > > > > > > >         virtio_cread_bytes(vdev, > > > > > > > >                    offsetof(struct virtio_net_config, mac), > > > > > > > >                    dev->dev_addr, dev->addr_len); > > > > > > > >     else > > > > > > > >         eth_hw_addr_random(dev); > > > > > > > > > > > > > > > > > > > > > > > > > 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 > > > > > > > > > > > > > > > > > > So for my understanding there are several method to fix this problem > > > > > > > > > > > > > > > > > > 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 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 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. > > > > > > 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: > > > > > > > > > > > > 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. > > > > > > > > > > > > > > > Consider VIRTIO_NET_CTRL_MAC_ADDR_SET is not supported now. What Eli > > > > > proposed here should work? > > > > > > > > > > Thanks > > > > > > > > > > > > > We can have management set a MAC address. Randomizing it in kernel > > > > does not seem like a reasonable policy to me ... > > > > > > > > > > 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. > > > > IIUC in this model devices are created by this tool, right? > > Why not require the MAC when device is created? > > > > It is mentioned in Parav's patchset that this will be coming in a > subsequent patch to his vdpa tool. So I think kernel has two options: - require a mac when device is created, we supply it to guest - allow guest to set a mac it's ok to support both ... > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >