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[23.128.96.18]) by mx.google.com with ESMTP id y23si191102edu.173.2020.11.30.03.55.51; Mon, 30 Nov 2020 03:56:13 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@nvidia.com header.s=n1 header.b="CyW/2lnh"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=nvidia.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729014AbgK3Lvw (ORCPT + 99 others); Mon, 30 Nov 2020 06:51:52 -0500 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:16985 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726197AbgK3Lvw (ORCPT ); Mon, 30 Nov 2020 06:51:52 -0500 Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Mon, 30 Nov 2020 03:51:20 -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; Mon, 30 Nov 2020 11:51:10 +0000 Date: Mon, 30 Nov 2020 13:51:06 +0200 From: Eli Cohen To: "Michael S. Tsirkin" CC: , , , Subject: Re: [PATCH] vdpa/mlx5: Use random MAC for the vdpa net instance Message-ID: <20201130115106.GC99449@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> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20201130043050-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: HQMAIL111.nvidia.com (172.20.187.18) To HQMAIL107.nvidia.com (172.20.187.13) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1606737080; bh=3Yjm2rXCYlzW1B54g8g6dZvWZtd9aaatA3YiUa/pRD8=; h=Date:From:To:CC:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To:User-Agent: X-Originating-IP:X-ClientProxiedBy; b=CyW/2lnhXTVaFPN4wgHeQVVFEfwTaybHzWlrbm2nyyF8j1PnCB0UgGxb3hbXTJ9LN 4s35cGBRJz0nlnahh77YIj89nQPqOGM8e15o4vC2otzEssKQH0qm4NG7AqAGt/zjlB zeuOVhtZPkE4xSMWW4O80upiB89k8P6xCjVeCPHEK0puFpoNqNWD0Q1I5teA3yHY4F uIC34f08MLTnCKgMWf08sJwD3a5dxHrvm0EYpTENc6UGay3girXBqWw5M78lyIWZre ndFRwsdcnp/F14BFaV/kGD0EcPZTCZVqjX/c9FM/Z1hlh8QO4lFrCzuKZ/rcRJpK+V cH3NhSiugTxvA== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 30, 2020 at 04:33:09AM -0500, 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. > OK, let's leave it for now. I will push along with the steering patches. The meaning is the the VDPA net device instance is create with a MAC of all zeros which also mean the link is down. You can set a MAC which will let the link come up. The vdpa driver will not get a callback as I stated but since current mode of steering directs all traffic to the vdpa instance it will work. In the future this must be fixed. > > > - 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? > vdpa config operation set_config() should be called whenever the MAC is changed, e.g. when administrator of the vdpa net device changes the mac. This does not happen which is a bug. > > > > > > > > > --- > > > > > > drivers/vdpa/mlx5/net/mlx5_vnet.c | 5 +---- > > > > > > 1 file changed, 1 insertion(+), 4 deletions(-) > > > > > > > > > > > > diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/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 mlx5_core_dev *mdev) > > > > > > if (err) > > > > > > goto err_mtu; > > > > > > > > > > > > - err = 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 = mdev->device; > > > > > > err = mlx5_vdpa_alloc_resources(&ndev->mvdev); > > > > > > if (err) > > > > > > -- > > > > > > 2.26.2 > > > > > > > > >