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 65E0DC433FE for ; Thu, 12 May 2022 05:57:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350048AbiELF5c (ORCPT ); Thu, 12 May 2022 01:57:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46546 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229575AbiELF5a (ORCPT ); Thu, 12 May 2022 01:57:30 -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 ESMTP id A088A24588 for ; Wed, 11 May 2022 22:57:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1652335047; 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=t0bDFb/tAAbguC+IHzTExFsJLrZiV0YVZh8GFZSOhC8=; b=fbQOa0cBLXisj8omCSSa4ehkiRuak1D7ivcAesdzCwyPCkjIpFVBDhbxqOg7VUuPmhAfZ6 octWV/1UHItnQOxUgU1TekOyCt/8d7Z3wC0QJzE1nU3bHpD8HMhrqygk6yEYzM+JQIHF3Q Xv63KST+A4DJ34yey/QX7nFIrmTt+RM= Received: from mail-ej1-f69.google.com (mail-ej1-f69.google.com [209.85.218.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-121-rHSAyJ5yNo-8U_8a8UXqrw-1; Thu, 12 May 2022 01:57:26 -0400 X-MC-Unique: rHSAyJ5yNo-8U_8a8UXqrw-1 Received: by mail-ej1-f69.google.com with SMTP id ga27-20020a1709070c1b00b006f43c161da4so2270624ejc.7 for ; Wed, 11 May 2022 22:57:26 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=t0bDFb/tAAbguC+IHzTExFsJLrZiV0YVZh8GFZSOhC8=; b=WgdkfyXmufa+iNqPt14gWCzk+Qi6HkDxZn97p0Tb0AWfxlIxbsEaQHUl2PESQ+txsc X/aLu4/FMRYQgnSDlWux4yz5eC2Pf2pz4bpYiN6BxcNaKv0UfBQXOSYOkqc/cxTUevpp QTR+eQ86nJmdbH1jWXGWurCW6+CeQZTNtB9L7vACUaJJVBrmk9JFhreKpdcocTd35B1q NWOAxwZvcSaECvS4vzNk74T8YN9MI16y6w9yCWOcouRp7qQTg6eKcsl/gHYObM9aV7Kw 8ZfuFbk0FcKii7Epydd4gIriIM0iPEEeu0lul+KmIJn558B0lxGsq1qLU/MIRWpFXEzw wXww== X-Gm-Message-State: AOAM531+rxyVmHUIHg7owoFeXbamXFBemR1dWVxQj9oBn90YK0wgODQa 7cntrhPJB2TL3cwVtwdtsnbCAGB9jpk18za/KV2aCe2uTa/sNYeasQxtd6NkzojPBPOhJ2k1NUx Zo3hzZpiKzvbd0rvsw9qe2bCh X-Received: by 2002:a05:6402:5188:b0:428:e77:b55b with SMTP id q8-20020a056402518800b004280e77b55bmr33524671edd.82.1652335044998; Wed, 11 May 2022 22:57:24 -0700 (PDT) X-Google-Smtp-Source: ABdhPJweg8gy0e+6m0LjjDG+u4kpvwZO9qOgpH3UsJkCBifxEoBTksWtM9DNoFbA6rp3Rsn/gvanVw== X-Received: by 2002:a05:6402:5188:b0:428:e77:b55b with SMTP id q8-20020a056402518800b004280e77b55bmr33524656edd.82.1652335044755; Wed, 11 May 2022 22:57:24 -0700 (PDT) Received: from redhat.com ([2.55.42.2]) by smtp.gmail.com with ESMTPSA id t5-20020a170906608500b006f4512e7bc8sm1716477ejj.60.2022.05.11.22.57.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 May 2022 22:57:24 -0700 (PDT) Date: Thu, 12 May 2022 01:57:20 -0400 From: "Michael S. Tsirkin" To: Eli Cohen Cc: jasowang@redhat.com, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, si-wei.liu@oracle.com Subject: Re: [PATCH v1] vdpa: Warn if MTU configured is too low Message-ID: <20220512014128-mutt-send-email-mst@kernel.org> References: <20220511105642.124806-1-elic@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220511105642.124806-1-elic@nvidia.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 11, 2022 at 01:56:42PM +0300, Eli Cohen wrote: > Following the recommendation in virio spec 1.1, a device offering > VIRTIO_NET_F_MTU should set the mtu to at least 1280 bytes. > > Print a warning if this recommendation is not met. > > Signed-off-by: Eli Cohen > --- > v0 -> v1: > chage pr_warn to netlink warning to userspace > > drivers/vdpa/vdpa.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c > index 91f4c13c7c7c..0fb4a615f267 100644 > --- a/drivers/vdpa/vdpa.c > +++ b/drivers/vdpa/vdpa.c > @@ -583,6 +583,9 @@ vdpa_nl_cmd_mgmtdev_get_dumpit(struct sk_buff *msg, struct netlink_callback *cb) > BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU) | \ > BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP)) > > +/* Recommended virtio spec 1.1 section 5.1.4.1 */ I'd add name of section here too. > +#define VIRTIO_MIN_PREFERRED_MTU 1280 > + Preferred is kind of confusing here. I guess you are trying to say it's not mandatory but I don't think this conveys this information. Recommended (matching text below)? > static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *info) > { > struct vdpa_dev_set_config config = {}; > @@ -634,6 +637,10 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *i > err = PTR_ERR(mdev); > goto err; > } > + if ((mdev->supported_features & BIT_ULL(VIRTIO_NET_F_MTU)) && > + (config.mask & BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU) && > + config.net.mtu < VIRTIO_MIN_PREFERRED_MTU)) > + NL_SET_ERR_MSG_MOD(info->extack, "MTU is below recommended value\n"); > if ((config.mask & mdev->config_attr_mask) != config.mask) { > NL_SET_ERR_MSG_MOD(info->extack, > "All provided attributes are not supported"); Pity we can't include the actual value here, but oh well. At least let's include the recommended value, we can do that: "MTU is below recommended value of " __stringify(VIRTIO_MIN_PREFERRED_MTU) "\n" > @@ -1135,7 +1142,7 @@ static const struct nla_policy vdpa_nl_policy[VDPA_ATTR_MAX + 1] = { > [VDPA_ATTR_DEV_NAME] = { .type = NLA_STRING }, > [VDPA_ATTR_DEV_NET_CFG_MACADDR] = NLA_POLICY_ETH_ADDR, > /* virtio spec 1.1 section 5.1.4.1 for valid MTU range */ > - [VDPA_ATTR_DEV_NET_CFG_MTU] = NLA_POLICY_MIN(NLA_U16, 68), > + [VDPA_ATTR_DEV_NET_CFG_MTU] = NLA_POLICY_MIN(NLA_U16, ETH_MIN_MTU), > }; > > static const struct genl_ops vdpa_nl_ops[] = { > -- > 2.35.1