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 Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 28F70C77B7C for ; Sun, 7 May 2023 08:59:12 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 9B315610FC; Sun, 7 May 2023 08:59:11 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp3.osuosl.org 9B315610FC Authentication-Results: smtp3.osuosl.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=MlCOsEfk X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id uHTMbi2sq85Z; Sun, 7 May 2023 08:59:10 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp3.osuosl.org (Postfix) with ESMTPS id F099E60F21; Sun, 7 May 2023 08:59:09 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp3.osuosl.org F099E60F21 Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id CD7CEC0037; Sun, 7 May 2023 08:59:09 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id 46138C002A for ; Sun, 7 May 2023 08:59:08 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 0C70181464 for ; Sun, 7 May 2023 08:59:08 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp1.osuosl.org 0C70181464 Authentication-Results: smtp1.osuosl.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=MlCOsEfk X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id NWci6JLBpb_k for ; Sun, 7 May 2023 08:59:07 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp1.osuosl.org 2F7668145C Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by smtp1.osuosl.org (Postfix) with ESMTPS id 2F7668145C for ; Sun, 7 May 2023 08:59:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1683449945; 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=yeeGTjp1K1OeCb3ZIEFft75WO1ELEw08OZwAFoljYwY=; b=MlCOsEfktIlfqWuKVQsf7MPlkA5KlLOAmzkznToc6T7l7a3wAbG7HXbcLVQqLU/KkXspiZ HbBLwnAXkNZJ6iES6y+DM5hKxZBoxUVHz1tCVIWO+/MliC45qtsz9tLCChvpndzct+AMwu ld8Po6og3reXRX8u4akSWwGC0HITbpQ= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-199-ofZN8bYFNUGooyZy7IDDjw-1; Sun, 07 May 2023 04:59:04 -0400 X-MC-Unique: ofZN8bYFNUGooyZy7IDDjw-1 Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-3f21e35dc08so13882275e9.2 for ; Sun, 07 May 2023 01:59:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683449943; x=1686041943; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=yeeGTjp1K1OeCb3ZIEFft75WO1ELEw08OZwAFoljYwY=; b=MeC9AwId0Ttck8kpaaaLVvJJuSfYgoWBAnk0sOu3v7+g01dKYBPxJCjtGS8Kjlo+YA 3CfRc9PAakxPUgugzPi4KcocczTYN+DWuiaeJxfhYGNBSDWEBcc5aaDvP+idnVJlmcri FVpng5hDZLH1ELiXAY8J92Sdcdeuw8f4LgS8NmzpOw8//mgfLOC9ELGUiBFm6denaELn qC6Ol9u881p/51tFyYZ8oZpZr4Z1guGOVY5fRSfDc442rkNkGqW7m67nBkNGHuON27k9 vkUYskQO3P3/v09eSq2P21PPUS9VEbVdOcxDFMMOaD4zICCatRR2tTW6Vx1ln6Li21OS /8eg== X-Gm-Message-State: AC+VfDxSa3SNXGZSrLwPYjFC9+9tRq445jRQjDsuMN6dfRHEI1zdZ012 CaOp6TLvDdojYLrE/qz/n1sGEdPd1pKeBiB1cEOCw9AvDPaKdkg1CcC9G1qogDsaSNIin82YGby NEAiBK63m7FxfK91t9tg1xyEkyxbFRz5Wds3tEkLikg== X-Received: by 2002:a05:600c:b4b:b0:3f2:73a:32fc with SMTP id k11-20020a05600c0b4b00b003f2073a32fcmr4521786wmr.32.1683449943590; Sun, 07 May 2023 01:59:03 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ7a9eutfAfd8aF4Cg4js80tavVGTVSzB9sy+7qygN//4rj17mi5XdK64Z91HAiqV/PL3Wlj8A== X-Received: by 2002:a05:600c:b4b:b0:3f2:73a:32fc with SMTP id k11-20020a05600c0b4b00b003f2073a32fcmr4521773wmr.32.1683449943324; Sun, 07 May 2023 01:59:03 -0700 (PDT) Received: from redhat.com ([2.52.158.28]) by smtp.gmail.com with ESMTPSA id e19-20020a05600c219300b003f173419e7asm12993148wme.43.2023.05.07.01.59.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 07 May 2023 01:59:02 -0700 (PDT) Date: Sun, 7 May 2023 04:58:58 -0400 From: "Michael S. Tsirkin" To: Hao Chen Subject: Re: [PATCH] virtio_net: set default mtu to 1500 when 'Device maximum MTU' bigger than 1500 Message-ID: <20230507045627-mutt-send-email-mst@kernel.org> References: <20230506021529.396812-1-chenh@yusur.tech> <1683341417.0965195-4-xuanzhuo@linux.alibaba.com> <07b6b325-9a15-222f-e618-d149b57cbac2@yusur.tech> MIME-Version: 1.0 In-Reply-To: <07b6b325-9a15-222f-e618-d149b57cbac2@yusur.tech> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Cc: Xuan Zhuo , zy@yusur.tech, "open list:NETWORKING DRIVERS" , open list , "open list:VIRTIO CORE AND NET DRIVERS" , Eric Dumazet , huangml@yusur.tech, Jakub Kicinski , Paolo Abeni , "David S. Miller" X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" T24gU2F0LCBNYXkgMDYsIDIwMjMgYXQgMDQ6NTY6MzVQTSArMDgwMCwgSGFvIENoZW4gd3JvdGU6 Cj4gCj4gCj4g5ZyoIDIwMjMvNS82IDEwOjUwLCBYdWFuIFpodW8g5YaZ6YGTOgo+ID4gT24gU2F0 LCAgNiBNYXkgMjAyMyAxMDoxNToyOSArMDgwMCwgSGFvIENoZW4gPGNoZW5oQHl1c3VyLnRlY2g+ IHdyb3RlOgo+ID4gPiBXaGVuIFZJUlRJT19ORVRfRl9NVFUoMykgRGV2aWNlIG1heGltdW0gTVRV IHJlcG9ydGluZyBpcyBzdXBwb3J0ZWQuCj4gPiA+IElmIG9mZmVyZWQgYnkgdGhlIGRldmljZSwg ZGV2aWNlIGFkdmlzZXMgZHJpdmVyIGFib3V0IHRoZSB2YWx1ZSBvZiBpdHMKPiA+ID4gbWF4aW11 bSBNVFUuIElmIG5lZ290aWF0ZWQsIHRoZSBkcml2ZXIgdXNlcyBtdHUgYXMgdGhlIG1heGltdW0K PiA+ID4gTVRVIHZhbHVlLiBCdXQgdGhlcmUgdGhlIGRyaXZlciBhbHNvIHVzZXMgaXQgYXMgZGVm YXVsdCBtdHUsCj4gPiA+IHNvbWUgZGV2aWNlcyBtYXkgaGF2ZSBhIG1heGltdW0gTVRVIGdyZWF0 ZXIgdGhhbiAxNTAwLCB0aGlzIG1heQo+ID4gPiBjYXVzZSBzb21lIGxhcmdlIHBhY2thZ2VzIHRv IGJlIGRpc2NhcmRlZCwKPiA+IAo+ID4gWW91IG1lYW4gdHggcGFja2V0Pwo+IFllcy4KPiA+IAo+ ID4gSWYgeWVzLCBJIGRvIG5vdCB0aGluayB0aGlzIGlzIHRoZSBwcm9ibGVtIG9mIGRyaXZlci4K PiA+IAo+ID4gTWF5YmUgeW91IHNob3VsZCBnaXZlIG1vcmUgZGV0YWlscyBhYm91dCB0aGUgZGlz Y2FyZC4KPiA+IAo+IEluIHRoZSBjdXJyZW50IGNvZGUsIGlmIHRoZSBtYXhpbXVtIE1UVSBzdXBw b3J0ZWQgYnkgdGhlIHZpcnRpbyBuZXQgaGFyZHdhcmUKPiBpcyA5MDAwLCB0aGUgZGVmYXVsdCBN VFUgb2YgdGhlIHZpcnRpbyBuZXQgZHJpdmVyIHdpbGwgYWxzbyBiZSBzZXQgdG8gOTAwMC4KPiBX aGVuIHNlbmRpbmcgcGFja2V0cyB0aHJvdWdoICJwaW5nIC1zIDUwMDAiLCBpZiB0aGUgcGVlciBy b3V0ZXIgZG9lcyBub3QKPiBzdXBwb3J0IG5lZ290aWF0aW5nIGEgcGF0aCBNVFUgdGhyb3VnaCBJ Q01QIHBhY2tldHMsIHRoZSBwYWNrZXRzIHdpbGwgYmUKPiBkaXNjYXJkZWQuIElmIHRoZSBwZWVy IHJvdXRlciBzdXBwb3J0cyBuZWdvdGlhdGluZyBwYXRoIG10dSB0aHJvdWdoIElDTVAKPiBwYWNr ZXRzLCB0aGUgaG9zdCBzaWRlIHdpbGwgcGVyZm9ybSBwYWNrZXQgc2hhcmRpbmcgcHJvY2Vzc2lu ZyBiYXNlZCBvbiB0aGUKPiBuZWdvdGlhdGVkIHBhdGggbXR1LCB3aGljaCBpcyBnZW5lcmFsbHkg d2l0aGluIDE1MDAuCj4gVGhpcyBpcyBub3QgYSBidWdmaXggcGF0Y2gsIEkgdGhpbmsgc2V0dGlu ZyB0aGUgZGVmYXVsdCBtdHUgdG8gd2l0aGluIDE1MDAKPiB3b3VsZCBiZSBtb3JlIHN1aXRhYmxl IGhlcmUuVGhhbmtzLgoKSSBkb24ndCB0aGluayBWSVJUSU9fTkVUX0ZfTVRVIGlzIGFwcHJvcHJp YXRlIGZvciBzdXBwb3J0IGZvciBqdW1ibyBwYWNrZXRzLgpUaGUgc3BlYyBzYXlzOgoJVGhlIGRl dmljZSBNVVNUIGZvcndhcmQgdHJhbnNtaXR0ZWQgcGFja2V0cyBvZiB1cCB0byBtdHUgKHBsdXMg bG93IGxldmVsIGV0aGVybmV0IGhlYWRlciBsZW5ndGgpIHNpemUgd2l0aAoJZ3NvX3R5cGUgTk9O RSBvciBFQ04sIGFuZCBkbyBzbyB3aXRob3V0IGZyYWdtZW50YXRpb24sIGFmdGVyIFZJUlRJT19O RVRfRl9NVFUgaGFzIGJlZW4gc3VjY2Vzcy0KCWZ1bGx5IG5lZ290aWF0ZWQuClZJUlRJT19ORVRf Rl9NVFUgaGFzIGJlZW4gZGVzaWduZWQgZm9yIGFsbCBraW5kIG9mIHR1bm5lbGluZyBkZXZpY2Vz LAphbmQgdGhpcyBpcyB3aHkgd2Ugc2V0IG10dSB0byBtYXggYnkgZGVmYXVsdC4KCkZvciB0aGlu Z3MgbGlrZSBqdW1ibyBmcmFtZXMgd2hlcmUgTVRVIG1pZ2h0IG9yIG1pZ2h0IG5vdCBiZSBhdmFp bGFibGUsCmEgbmV3IGZlYXR1cmUgd291bGQgYmUgbW9yZSBhcHByb3ByaWF0ZS4KCj4gPiA+IHNv IEkgY2hhbmdlZCB0aGUgTVRVIHRvIGEgbW9yZQo+ID4gPiBnZW5lcmFsIDE1MDAgd2hlbiAnRGV2 aWNlIG1heGltdW0gTVRVJyBiaWdnZXIgdGhhbiAxNTAwLgo+ID4gPiAKPiA+ID4gU2lnbmVkLW9m Zi1ieTogSGFvIENoZW4gPGNoZW5oQHl1c3VyLnRlY2g+Cj4gPiA+IC0tLQo+ID4gPiAgIGRyaXZl cnMvbmV0L3ZpcnRpb19uZXQuYyB8IDUgKysrKy0KPiA+ID4gICAxIGZpbGUgY2hhbmdlZCwgNCBp bnNlcnRpb25zKCspLCAxIGRlbGV0aW9uKC0pCj4gPiA+IAo+ID4gPiBkaWZmIC0tZ2l0IGEvZHJp dmVycy9uZXQvdmlydGlvX25ldC5jIGIvZHJpdmVycy9uZXQvdmlydGlvX25ldC5jCj4gPiA+IGlu ZGV4IDhkODAzODUzOGZjNC4uZTcxYzdkMWI1ZjI5IDEwMDY0NAo+ID4gPiAtLS0gYS9kcml2ZXJz L25ldC92aXJ0aW9fbmV0LmMKPiA+ID4gKysrIGIvZHJpdmVycy9uZXQvdmlydGlvX25ldC5jCj4g PiA+IEBAIC00MDQwLDcgKzQwNDAsMTAgQEAgc3RhdGljIGludCB2aXJ0bmV0X3Byb2JlKHN0cnVj dCB2aXJ0aW9fZGV2aWNlICp2ZGV2KQo+ID4gPiAgIAkJCWdvdG8gZnJlZTsKPiA+ID4gICAJCX0K PiA+ID4gCj4gPiA+IC0JCWRldi0+bXR1ID0gbXR1Owo+ID4gPiArCQlpZiAobXR1ID4gMTUwMCkK PiA+IAo+ID4gcy8xNTAwL0VUSF9EQVRBX0xFTi8KPiA+IAo+ID4gVGhhbmtzLgo+ID4gCj4gPiA+ ICsJCQlkZXYtPm10dSA9IDE1MDA7Cj4gPiA+ICsJCWVsc2UKPiA+ID4gKwkJCWRldi0+bXR1ID0g bXR1Owo+ID4gPiAgIAkJZGV2LT5tYXhfbXR1ID0gbXR1Owo+ID4gPiAgIAl9Cj4gPiA+IAo+ID4g PiAtLQo+ID4gPiAyLjI3LjAKPiA+ID4gCgpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fXwpWaXJ0dWFsaXphdGlvbiBtYWlsaW5nIGxpc3QKVmlydHVhbGl6YXRp b25AbGlzdHMubGludXgtZm91bmRhdGlvbi5vcmcKaHR0cHM6Ly9saXN0cy5saW51eGZvdW5kYXRp b24ub3JnL21haWxtYW4vbGlzdGluZm8vdmlydHVhbGl6YXRpb24= 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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E7AD8C77B75 for ; Sun, 7 May 2023 08:59:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230090AbjEGI7z (ORCPT ); Sun, 7 May 2023 04:59:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38210 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229757AbjEGI7x (ORCPT ); Sun, 7 May 2023 04:59:53 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A59151161F for ; Sun, 7 May 2023 01:59:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1683449945; 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=yeeGTjp1K1OeCb3ZIEFft75WO1ELEw08OZwAFoljYwY=; b=MlCOsEfktIlfqWuKVQsf7MPlkA5KlLOAmzkznToc6T7l7a3wAbG7HXbcLVQqLU/KkXspiZ HbBLwnAXkNZJ6iES6y+DM5hKxZBoxUVHz1tCVIWO+/MliC45qtsz9tLCChvpndzct+AMwu ld8Po6og3reXRX8u4akSWwGC0HITbpQ= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-80-lYGFP4NHMlKtWt6oUASxOw-1; Sun, 07 May 2023 04:59:04 -0400 X-MC-Unique: lYGFP4NHMlKtWt6oUASxOw-1 Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-3f21e35dc08so13882305e9.2 for ; Sun, 07 May 2023 01:59:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683449943; x=1686041943; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=yeeGTjp1K1OeCb3ZIEFft75WO1ELEw08OZwAFoljYwY=; b=Gcu+15tKrKvGMeFsc02B0kvtNJVZJzrrmz9SO2flukx/tyQs3kxaMcvrbWTzUoRJOg 7JfkGB7QsWGcIUVW0jAFkkVeqFhbs95UcPH1fpucUoyEJcyvzmWJ6ubzDC7XnusqdXUG nT6Pz/2PkBHnuUDtR6fd8s4bjXZ3gAVi8vtLUB1gMIhM9VcysRiVb9KJ312vfUFuX53V BI0cuicExMYu2SX6Vu1sCbfDDLd43ltsg2aZ9k+IPWLWCaq6fIDIybIuL8Hn4UHNYBiK /MvkIRG1tBZ2AnZjvrvjlCedHJ2eX9YkS7cyNcNPGzN+dOM6QFMKasL3owUkH5epwUh6 1geA== X-Gm-Message-State: AC+VfDzaXJOk5Op8uEskAgmBNFUOnRkIe736NfYTrhr/puNbZbj0XLna HtEpUyYrcDe5XKqzzTyapMNHZKBhsj1e0vzGxAropfwkiVIwbxY3XGUSMUrlkvAISfKFZcOXxsl Q27T9++0DvsGgigFB4i34NnYT X-Received: by 2002:a05:600c:b4b:b0:3f2:73a:32fc with SMTP id k11-20020a05600c0b4b00b003f2073a32fcmr4521784wmr.32.1683449943589; Sun, 07 May 2023 01:59:03 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ7a9eutfAfd8aF4Cg4js80tavVGTVSzB9sy+7qygN//4rj17mi5XdK64Z91HAiqV/PL3Wlj8A== X-Received: by 2002:a05:600c:b4b:b0:3f2:73a:32fc with SMTP id k11-20020a05600c0b4b00b003f2073a32fcmr4521773wmr.32.1683449943324; Sun, 07 May 2023 01:59:03 -0700 (PDT) Received: from redhat.com ([2.52.158.28]) by smtp.gmail.com with ESMTPSA id e19-20020a05600c219300b003f173419e7asm12993148wme.43.2023.05.07.01.59.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 07 May 2023 01:59:02 -0700 (PDT) Date: Sun, 7 May 2023 04:58:58 -0400 From: "Michael S. Tsirkin" To: Hao Chen Cc: Xuan Zhuo , huangml@yusur.tech, zy@yusur.tech, Jason Wang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , "open list:VIRTIO CORE AND NET DRIVERS" , "open list:NETWORKING DRIVERS" , open list Subject: Re: [PATCH] virtio_net: set default mtu to 1500 when 'Device maximum MTU' bigger than 1500 Message-ID: <20230507045627-mutt-send-email-mst@kernel.org> References: <20230506021529.396812-1-chenh@yusur.tech> <1683341417.0965195-4-xuanzhuo@linux.alibaba.com> <07b6b325-9a15-222f-e618-d149b57cbac2@yusur.tech> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <07b6b325-9a15-222f-e618-d149b57cbac2@yusur.tech> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 06, 2023 at 04:56:35PM +0800, Hao Chen wrote: > > > 在 2023/5/6 10:50, Xuan Zhuo 写道: > > On Sat, 6 May 2023 10:15:29 +0800, Hao Chen wrote: > > > When VIRTIO_NET_F_MTU(3) Device maximum MTU reporting is supported. > > > If offered by the device, device advises driver about the value of its > > > maximum MTU. If negotiated, the driver uses mtu as the maximum > > > MTU value. But there the driver also uses it as default mtu, > > > some devices may have a maximum MTU greater than 1500, this may > > > cause some large packages to be discarded, > > > > You mean tx packet? > Yes. > > > > If yes, I do not think this is the problem of driver. > > > > Maybe you should give more details about the discard. > > > In the current code, if the maximum MTU supported by the virtio net hardware > is 9000, the default MTU of the virtio net driver will also be set to 9000. > When sending packets through "ping -s 5000", if the peer router does not > support negotiating a path MTU through ICMP packets, the packets will be > discarded. If the peer router supports negotiating path mtu through ICMP > packets, the host side will perform packet sharding processing based on the > negotiated path mtu, which is generally within 1500. > This is not a bugfix patch, I think setting the default mtu to within 1500 > would be more suitable here.Thanks. I don't think VIRTIO_NET_F_MTU is appropriate for support for jumbo packets. The spec says: The device MUST forward transmitted packets of up to mtu (plus low level ethernet header length) size with gso_type NONE or ECN, and do so without fragmentation, after VIRTIO_NET_F_MTU has been success- fully negotiated. VIRTIO_NET_F_MTU has been designed for all kind of tunneling devices, and this is why we set mtu to max by default. For things like jumbo frames where MTU might or might not be available, a new feature would be more appropriate. > > > so I changed the MTU to a more > > > general 1500 when 'Device maximum MTU' bigger than 1500. > > > > > > Signed-off-by: Hao Chen > > > --- > > > drivers/net/virtio_net.c | 5 ++++- > > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > > index 8d8038538fc4..e71c7d1b5f29 100644 > > > --- a/drivers/net/virtio_net.c > > > +++ b/drivers/net/virtio_net.c > > > @@ -4040,7 +4040,10 @@ static int virtnet_probe(struct virtio_device *vdev) > > > goto free; > > > } > > > > > > - dev->mtu = mtu; > > > + if (mtu > 1500) > > > > s/1500/ETH_DATA_LEN/ > > > > Thanks. > > > > > + dev->mtu = 1500; > > > + else > > > + dev->mtu = mtu; > > > dev->max_mtu = mtu; > > > } > > > > > > -- > > > 2.27.0 > > >