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=0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MISSING_SUBJECT,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 2DBF2C4BA0B for ; Wed, 26 Feb 2020 09:37:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0161A20732 for ; Wed, 26 Feb 2020 09:37:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="FvhgbXTb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727888AbgBZJhD (ORCPT ); Wed, 26 Feb 2020 04:37:03 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:44745 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727377AbgBZJhD (ORCPT ); Wed, 26 Feb 2020 04:37:03 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582709821; h=from:from:reply-to:subject:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type; bh=05Q/qlazrQBQgStNZTgqIbMF3rU50l1dnIw6ldFHuqo=; b=FvhgbXTbaALL87p60TlQeMIKqelJId3Rpd8FHKn2knNOndWIZKUbpikEtNer8DYM1VSZyE H5NahyM+LEu1U+tXN1tT1r2HfAlOdSL1rZjkuDdH3kusNGbNdW5tQUBxM8He3+nnflCeCQ 0w3eeUmCNN4kx43hb/IPrRQ8UgJ2Yj8= Received: from mail-qk1-f197.google.com (mail-qk1-f197.google.com [209.85.222.197]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-19-0c0GoxjWM-2d9MU2N1NjaA-1; Wed, 26 Feb 2020 04:33:35 -0500 X-MC-Unique: 0c0GoxjWM-2d9MU2N1NjaA-1 Received: by mail-qk1-f197.google.com with SMTP id c66so3346565qkb.13 for ; Wed, 26 Feb 2020 01:33:35 -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:message-id:mime-version :content-disposition; bh=05Q/qlazrQBQgStNZTgqIbMF3rU50l1dnIw6ldFHuqo=; b=kPh1FVRUClbYfEi7cZLZbeu6zLuSIRoEcgGtpl9g64dM9VU76fmSgZ9PKItimdtsq3 B4ianvdfGV93C+1W4rZiJ4cggacgvn/8CxPgirTAqpxXEsXnh/j5k1j6T5ZBzFwoAp4x PdaEsh3xKDRkTrySEopEQTHrjE2pqzteSmpJU/IL/u1/SJK24rMREicd0/kmEoQnhfxq 3tug5XkC/8KUx/DX183nWjRMFaPWqHOnB6uWhL7vFGVlHXlGFdirRxLEEk9+Az+6zFlZ vNoPFJWDIKQXQyPx8C+9ubuxeU3lIo5IELMrKnWSOy+35Ea17uziKZAjNv7pPY4lX+Qh uFJQ== X-Gm-Message-State: APjAAAVRIdsGAHeeXSfOjfn8+gMBNP+9hloE3c5t8NGYv00ppFTx6xBU Elt+QsAB91O1v6ptHNP+r+WaqOfTw5v5j8RzdGU0HPqS1V/BcwRhRId0bGTCVer6r5okd7J1UKc /774PPqT675Gj/6vO X-Received: by 2002:aed:2ac5:: with SMTP id t63mr3770159qtd.315.1582709614767; Wed, 26 Feb 2020 01:33:34 -0800 (PST) X-Google-Smtp-Source: APXvYqxhSm+8kGUuG7I8PAOwYtVo9vMvCK3WLApUZUDftOhMv3ipbXs6XgACJ2Ya8Vhko7yAhKwqNw== X-Received: by 2002:aed:2ac5:: with SMTP id t63mr3770130qtd.315.1582709614464; Wed, 26 Feb 2020 01:33:34 -0800 (PST) Received: from redhat.com (bzq-79-178-2-214.red.bezeqint.net. [79.178.2.214]) by smtp.gmail.com with ESMTPSA id w2sm793255qtd.97.2020.02.26.01.33.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Feb 2020 01:33:33 -0800 (PST) Date: Wed, 26 Feb 2020 04:33:30 -0500 From: "Michael S. Tsirkin" To: David Ahern Cc: Jason Wang , "netdev@vger.kernel.org" , Toke =?iso-8859-1?Q?H=F8iland-J=F8rgensen?= Message-ID: <20200226093330.GA711395@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Bcc: Subject: Re: virtio_net: can change MTU after installing program Message-ID: <20200226043257-mutt-send-email-mst@kernel.org> Reply-To: In-Reply-To: <7df5bb7f-ea69-7673-642b-f174e45a1e64@digitalocean.com> On Tue, Feb 25, 2020 at 08:32:14PM -0700, David Ahern wrote: > Another issue is that virtio_net checks the MTU when a program is > installed, but does not restrict an MTU change after: > > # ip li sh dev eth0 > 2: eth0: mtu 1500 xdp qdisc fq_codel > state UP mode DEFAULT group default qlen 1000 > link/ether 5a:39:e6:01:a5:36 brd ff:ff:ff:ff:ff:ff > prog/xdp id 13 tag c5595e4590d58063 jited > > # ip li set dev eth0 mtu 8192 > > # ip li sh dev eth0 > 2: eth0: mtu 8192 xdp qdisc fq_codel > state UP mode DEFAULT group default qlen 1000 > > Cc Toke who has tested this on other cards and has some input. -- MST