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 45CD6C77B76 for ; Sun, 23 Apr 2023 11:10:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229805AbjDWLKi (ORCPT ); Sun, 23 Apr 2023 07:10:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33102 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229478AbjDWLKa (ORCPT ); Sun, 23 Apr 2023 07:10:30 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 34F0D1986 for ; Sun, 23 Apr 2023 04:09:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1682248180; 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: in-reply-to:in-reply-to:references:references; bh=qa5an+pMO/z37xFkKNIb5d1qvmQCeDMySUintGMWRFc=; b=hZyAQxig93D7opNlNrGlV4Jhqzaygjfsz6q5Xby9xzIz0d10eqjwoyZnkCxeQIwxp4ITrq 8n1uaorOvEwg7zudRvc+OyZH1WhQDHFaQSwFU4jEbQxHGDMKnQj3hipmbPl/T5GR4msyde rjjOq/8imvravYahmDO0o6LzRnZRzfA= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-83-SNE_YGByO_28LXI-bAfTUg-1; Sun, 23 Apr 2023 07:09:39 -0400 X-MC-Unique: SNE_YGByO_28LXI-bAfTUg-1 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-3f171d201afso19887425e9.0 for ; Sun, 23 Apr 2023 04:09:38 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1682248178; x=1684840178; h=in-reply-to: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=qa5an+pMO/z37xFkKNIb5d1qvmQCeDMySUintGMWRFc=; b=W1aEnFiOc9bw0L54FZ5Yo+Bzfx/MAgP3LeIhTBA7AbMd7kPEllsrTI3K0x7MzLvHmz eqv4ePKLKgV3W61reP/96v1RSKhoEuqcidweeJj+CPdDCtreYoK2ERy3UYZrhrafHZAO LJSOTbumKE015sWb/J43H5+ziK1aOIxVn0qABFZ29MrA8ldpp2Pd3How08f1K6mweN6J tJp/KeEftFUedW31UAcqkHA4b2hs9IkYsnOEe9hQ86KW23BhoHc0YE9d3MNBdGb3+pzQ DjUvoXeoa3F1KnY16OSstv9sSn7B3UB9J4iafEqlwqxEGn2MdWKaVt3Pq7FFpml5+h6Q TVCA== X-Gm-Message-State: AAQBX9eHZAddVVyLckA9PBL2UIPbRnC/qlNnOFOkp+13IOEdwv9RLIWq JPKltFtiCcdRQSHJ7p6/Fz4x4To7/feDjOvkKfy2gHoFPuO0f2t7ZOetsQ24j2SWHZz3aa54sxG S/cYgPGrNYPeVvu3yEDfu0IHT X-Received: by 2002:a05:6000:1091:b0:2fb:1d3a:93ff with SMTP id y17-20020a056000109100b002fb1d3a93ffmr7134585wrw.61.1682248177956; Sun, 23 Apr 2023 04:09:37 -0700 (PDT) X-Google-Smtp-Source: AKy350aV4IFxLAe3RJ8HQ8N5xqnVRos1U8Sc00vmSPnpomKazzuEb3lleaW1Py4Fcaqvh482tdyrOA== X-Received: by 2002:a05:6000:1091:b0:2fb:1d3a:93ff with SMTP id y17-20020a056000109100b002fb1d3a93ffmr7134574wrw.61.1682248177654; Sun, 23 Apr 2023 04:09:37 -0700 (PDT) Received: from redhat.com ([2.55.61.39]) by smtp.gmail.com with ESMTPSA id bi26-20020a05600c3d9a00b003eddc6aa5fasm9043356wmb.39.2023.04.23.04.09.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 23 Apr 2023 04:09:37 -0700 (PDT) Date: Sun, 23 Apr 2023 07:09:33 -0400 From: "Michael S. Tsirkin" To: Alvaro Karsz Cc: "jasowang@redhat.com" , "davem@davemloft.net" , "edumazet@google.com" , "kuba@kernel.org" , "pabeni@redhat.com" , "virtualization@lists.linux-foundation.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH net] virtio-net: reject small vring sizes Message-ID: <20230423070849-mutt-send-email-mst@kernel.org> References: <20230416074607.292616-1-alvaro.karsz@solid-run.com> <20230416163751-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 17, 2023 at 06:43:39AM +0000, Alvaro Karsz wrote: > > > +static int virtnet_validate_vqs(struct virtnet_info *vi) > > > +{ > > > + u32 i, min_size = roundup_pow_of_two(MAX_SKB_FRAGS + 2); > > > > why power of two? > > The ring size is always a power of 2, Not really, packed rings allow non power of 2. Linux had a bug that it required power of 2 for packed, but we are fixing that finally. > so checking against > MAX_SKB_FRAGS + 2 or against roundup_pow_of_two will result in the > same, and I think that printing the warning with the actual min value > is more helpful. I can check the condition against MAX_SKB_FRAGS + 2, > and print the rounded value in case of an error. >