From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3B58432AADF for ; Tue, 25 Nov 2025 17:57:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764093479; cv=none; b=HSv3Kntpof3I3miKvJUBDvecyQ9r7gXWrfJgZp0It81UV3pjDuZGqEE2SFHZWZ+Hz111Q8Rur/KqbC1P8D3ejAIFysg6Sxf6IXIku+b2XbYWnzrxiGfEDcQ0ro70KhVmLBXKNi985/j+GlNcrxiJnyLyZmfew66xiI3cqd7ikIw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764093479; c=relaxed/simple; bh=Fs83rTTPnZoefNeB88lzRj2Zrxjcng2SgqTDnxbSr4E=; h=Message-ID:Date:MIME-Version:Subject:To:References:Cc:From: In-Reply-To:Content-Type; b=XY+oeAf6CBjapfpdWGo9ftv4HmCTTUukgoUBU6Nyw6OnuUYiNOsJFz1HipdRip2GDzjFileDeUNiUe+6Y7p3Tm71dhLJXQ2CaTjJMAqjOdi98yRPDqJAn9KXxQxfEEMi1Q3ClUwudjlDDM1xt2jxYt1xzYoffZTdRW4JYLK8/DI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Y5bQgufv; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=EBtcRsbk; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Y5bQgufv"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="EBtcRsbk" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1764093475; 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=LBBNljc5iFCuzwl9ZqmN5RW/+AydF/L+sgiYuUnYeUI=; b=Y5bQgufvfS1kc6EJ0PM0Kf+bFHTfgvbivCiAiUYI1dvjYs9grAwQD+XXKnN+RmQ6LIN1jY tHxgklH4NzDkrU1o4K29o7HgYzuERa0njo2SRjQhik6xGIyTDn4bUDrT5i8N69qZ7XYnuq NqFL5ThMH3EkAAUzaYaghBwRJkciDYQ= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-562-wNN36i0FORmQZDrMa1CJOw-1; Tue, 25 Nov 2025 12:57:53 -0500 X-MC-Unique: wNN36i0FORmQZDrMa1CJOw-1 X-Mimecast-MFC-AGG-ID: wNN36i0FORmQZDrMa1CJOw_1764093471 Received: by mail-wr1-f70.google.com with SMTP id ffacd0b85a97d-429cceeeb96so3549606f8f.1 for ; Tue, 25 Nov 2025 09:57:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1764093471; x=1764698271; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:cc:content-language :references:to:subject:user-agent:mime-version:date:message-id:from :to:cc:subject:date:message-id:reply-to; bh=LBBNljc5iFCuzwl9ZqmN5RW/+AydF/L+sgiYuUnYeUI=; b=EBtcRsbkSkCfEefAfNxcybFPpk8rYU7rLgqPv/9EbVWn4U4BgpU1G4F83/5fdJoVsT fGs/+MjFpjroLPBHJcluoAACC0MXzz8/20H3cXlklrATi4M3f32Feb9Ccwea7qZx7j15 x9AgkukFjIvJEvDns4i0v1ydGqwph7VspRUuOm1VVsaj6TMSfI7z33rk2LDT+lRrMmyP hYfmTEAwNY6N69kGDZBaC80ZFGzFaGOFYMqWq8RhT3yls1VBo3b28m8AFeB4OJNJOGKn NYaWoqyvKW4RsLOuoNJyZYB9Kf6wJh87kQxTbVpwSX/eitIv6kPCnzEbYrhomxVDljMd m/KQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1764093471; x=1764698271; h=content-transfer-encoding:in-reply-to:from:cc:content-language :references:to:subject:user-agent:mime-version:date:message-id :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=LBBNljc5iFCuzwl9ZqmN5RW/+AydF/L+sgiYuUnYeUI=; b=URRMEnsm6RnYMUO5vU7pXFMsxFSM6KdrxTkR47gmj6TsSGttquRi4IR9OzpkPGs52U Ak7ChvkPqAn+9B8RoRjLTtbl0PSxRbNE2QHTWSvtZEFn9WMEJJ7dS8byOFKDYp0wjhPI DpcBxeaKvAOLFnffNnkUJdj+TaBQkYzDNt6Vd62sfBPmEH7SbB9y+ERCSCSIgqKFDRx3 AnO06n13Ktl4JMUno3OLNEJlWmf8tJ5P2HfLrjHd8+m8XPFSL2zFBM/L3IRk+2a/VG6k ARr8RKGka5gu/gqxkkZBeDTdOSXOkw6hAe+p7s4zIgZMACNZiZ2DsWvNx2rA8Qv7yiit TXhg== X-Forwarded-Encrypted: i=1; AJvYcCVD/X3Kqd95+zWSprnMG5RxPcPlaig7oY94CdULsfp478LcQQBcScYLzw45jW4kYDCpDRCYv9JLbE2hcPI=@vger.kernel.org X-Gm-Message-State: AOJu0Yw/IuOfAyuEOZh4YKCo4vPa2a+ByQ6LJlZNRQcI0Ob6PYFnp/xo WscWCl8O+4gCnxJA3nRjMH7YD4QHRFfeUls5NU/kSjBBtEuQAcHzO+acFY00fT4HzSsi1KKZW/Y di1EB/zKWP5KK1aY/VDxSMc4S25j5R5GfLuDgS+GxLJdolONcY8yO7kNNtX/JbMMM7w== X-Gm-Gg: ASbGncuOV70giDLsMwu6Y9ydcvB6ivbaE7OgXUFQIOCXWhgo4TAxJoqjtY54OVOjnQA GEC4szZw/zho/Kd8xE1eQpOmEyGopoPHZU4bpSphjc+Amn8QDvZChy5YvaLF2juymeifoa0jRpC 6tmovH/iXd+7i2hVNVtnlA7dDGmJuTTCdo2LeZxq7hlblrjRi9i7E+BC8CaQF1RH0kaoiAPAuCr GOqQPvoTSSU5C+mfvJVHNPVU/rqNk7jr8RE2DNqBMgZSwmrc0eRJ0PRPR4kxvbyjAIkp7xbdNO7 8aU84+SqJbHJop3pUkcUd4PMzqcomQF1/MQReJz788+doC5QvDQhtK7u1CPvT/WtN2uOQ9BZigE CEEBYkmFj7YOlFQ== X-Received: by 2002:a05:6000:430a:b0:42b:3246:1681 with SMTP id ffacd0b85a97d-42cc1accdd6mr17107047f8f.18.1764093470972; Tue, 25 Nov 2025 09:57:50 -0800 (PST) X-Google-Smtp-Source: AGHT+IHo3snX1o9Z22+ePohjUgGpFTEU10kI9WW/GDIDglDYteMzSXiD2riD2Rl+m2cCB65iYkPtyg== X-Received: by 2002:a05:6000:430a:b0:42b:3246:1681 with SMTP id ffacd0b85a97d-42cc1accdd6mr17107029f8f.18.1764093470584; Tue, 25 Nov 2025 09:57:50 -0800 (PST) Received: from [192.168.88.32] ([212.105.153.231]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-42cb7fa3a76sm35703266f8f.24.2025.11.25.09.57.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 25 Nov 2025 09:57:50 -0800 (PST) Message-ID: <276828c5-72cb-4f5c-bc6f-7937aa6b6303@redhat.com> Date: Tue, 25 Nov 2025 18:57:49 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next] virtio-net: avoid unnecessary checksum calculation on guest RX To: Jon Kohler , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?Q?Eugenio_P=C3=A9rez?= , virtualization@lists.linux.dev, linux-kernel@vger.kernel.org References: <20251125175117.995179-1-jon@nutanix.com> Content-Language: en-US Cc: "netdev@vger.kernel.org" From: Paolo Abeni In-Reply-To: <20251125175117.995179-1-jon@nutanix.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit CC netdev On 11/25/25 6:51 PM, Jon Kohler wrote: > Commit a2fb4bc4e2a6 ("net: implement virtio helpers to handle UDP > GSO tunneling.") inadvertently altered checksum offload behavior > for guests not using UDP GSO tunneling. > > Before, tun_put_user called tun_vnet_hdr_from_skb, which passed > has_data_valid = true to virtio_net_hdr_from_skb. > > After, tun_put_user began calling tun_vnet_hdr_tnl_from_skb instead, > which passes has_data_valid = false into both call sites. > > This caused virtio hdr flags to not include VIRTIO_NET_HDR_F_DATA_VALID > for SKBs where skb->ip_summed == CHECKSUM_UNNECESSARY. As a result, > guests are forced to recalculate checksums unnecessarily. > > Restore the previous behavior by ensuring has_data_valid = true is > passed in the !tnl_gso_type case. > > Cc: Paolo Abeni > Fixes: a2fb4bc4e2a6 ("net: implement virtio helpers to handle UDP GSO tunneling.") > Signed-off-by: Jon Kohler > --- > include/linux/virtio_net.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h > index b673c31569f3..570c6dd1666d 100644 > --- a/include/linux/virtio_net.h > +++ b/include/linux/virtio_net.h > @@ -394,7 +394,7 @@ virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb, > tnl_gso_type = skb_shinfo(skb)->gso_type & (SKB_GSO_UDP_TUNNEL | > SKB_GSO_UDP_TUNNEL_CSUM); > if (!tnl_gso_type) > - return virtio_net_hdr_from_skb(skb, hdr, little_endian, false, > + return virtio_net_hdr_from_skb(skb, hdr, little_endian, true, > vlan_hlen); > > /* Tunnel support not negotiated but skb ask for it. */ virtio_net_hdr_tnl_from_skb() is used also by the virtio_net driver, which in turn must not use VIRTIO_NET_HDR_F_DATA_VALID on tx. I think you need to add another argument to virtio_net_hdr_tnl_from_skb(), or possibly implement a separate helper to take care of csum offload - the symmetric of virtio_net_handle_csum_offload(). Also you need to CC netdev, otherwise the patch will not be processed by patchwork. /P