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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 D6DA2C3F2C2 for ; Thu, 27 Feb 2020 21:37:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8B9524690 for ; Thu, 27 Feb 2020 21:37:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=digitalocean.com header.i=@digitalocean.com header.b="YAQh2d+L" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729831AbgB0Vh2 (ORCPT ); Thu, 27 Feb 2020 16:37:28 -0500 Received: from mail-qk1-f169.google.com ([209.85.222.169]:42892 "EHLO mail-qk1-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729726AbgB0Vh2 (ORCPT ); Thu, 27 Feb 2020 16:37:28 -0500 Received: by mail-qk1-f169.google.com with SMTP id o28so983958qkj.9 for ; Thu, 27 Feb 2020 13:37:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=digitalocean.com; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=u9MU1m+iz8JAHrcyaPeyXeuYCFzczILJ1w8YtSbL4JM=; b=YAQh2d+LsAxiqBASmp2Sp2+ivQHQ0jS3c7MKFQHokvkJXS29fNOP5TBOa6bZQnZqOv VQJ1VEmAXV5tHwwM8BfDnnpMVtEX0mmFzuuh85h6y11dFhQKfHQ0l1J1wxswosKFCL9o l6nyITe91Q5OU/9IPY0kNOtu4G/Ww/Ph1K3M8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=u9MU1m+iz8JAHrcyaPeyXeuYCFzczILJ1w8YtSbL4JM=; b=SCuMJfbqWSDfEl5pvQZQpU7+1CYw47bpnICF4u5H3CASctsSl5KKVQfEf5TtI2ix5q TktssBmy10OE+VDtltpUUo8qb2fy8PXZCCiXNQ3WKK55D+EGeWf/TDJCia3ys5olu5zM 1bGIxwb53FjCNGZOKagddBJytMuJyuDr2gVLFqiv/xEGEYFVhrLvXOe5R6AQPhUKmZfj xIdKSSjaemeTPh+DEVY1BVrL2c2f+pxe2eiPspMI9ul9Ys2NsWuNg4s7qaGPK5Lh9xP4 oergbGgGk92cij++N9hKapOLs2thna8lT6cYT4m3220N0eAV7Ti65xDdS0RfLz0b78Ul fFfw== X-Gm-Message-State: APjAAAW62UVkoAbY6mMOouW5f0/+jDlXupVythqDO9L3bXYW7MQ+JGzL aGsAiPKDMVlQiEXEf5c/acJHXQ== X-Google-Smtp-Source: APXvYqwQdvyu0bVGafUsE/LzhfnKUsnOBO96G4vT1yFM9D862b6nwrzDN8EXg78FJkLz891qGHGBgg== X-Received: by 2002:a37:e0d:: with SMTP id 13mr1520845qko.145.1582839447769; Thu, 27 Feb 2020 13:37:27 -0800 (PST) Received: from ?IPv6:2601:282:803:7700:a58e:e5e0:4900:6bcd? ([2601:282:803:7700:a58e:e5e0:4900:6bcd]) by smtp.gmail.com with ESMTPSA id z27sm3834617qtv.11.2020.02.27.13.37.26 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 27 Feb 2020 13:37:26 -0800 (PST) Subject: Re: virtio_net: can change MTU after installing program To: Michael Chan , Jakub Kicinski Cc: "Michael S. Tsirkin" , =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , Jason Wang , "netdev@vger.kernel.org" , Andy Gospodarek References: <20200226093330.GA711395@redhat.com> <87lfopznfe.fsf@toke.dk> <0b446fc3-01ed-4dc1-81f0-ef0e1e2cadb0@digitalocean.com> <20200226115258-mutt-send-email-mst@kernel.org> <20200226120142-mutt-send-email-mst@kernel.org> <20200226173751.0b078185@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> From: David Ahern Message-ID: <7c00848a-51b0-254e-31f7-65fc3741227f@digitalocean.com> Date: Thu, 27 Feb 2020 14:37:25 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.4.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2/27/20 12:26 PM, Michael Chan wrote: > > The Broadcom bnxt_en driver should not allow the MTU to be changed to > an invalid value after an XDP program is attached. We set the > netdev->max_mtu to a smaller value and dev_validate_mtu() should > reject MTUs that are not supported in XDP mode. > That's what I proposed for virtio_net. Simplest option and since max mtu is now dumped with device details very easy for a user to determine why a particular MTU fails.