From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 74AF435C1AE; Fri, 27 Mar 2026 03:20:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774581628; cv=none; b=MfFh3smtz0sAl/lbVuWSAE6czwKzpXT82n1Lgb3FKy0BJbV9iuOeBxJ4PQuK5+qcS5z0PrQJDujsNXoCYsp/9vPrEHzhXosWcaA1DVr+kp4w+RDzLncnby52LQpeLz9BuYE+h3W1NCCDXqO48qr1QBZqPkaHVIQTV9x2wWntP5c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774581628; c=relaxed/simple; bh=NMNqDhrPaal3Yltv8RJLavSk/i9ysKkz0fwPnx3hNL8=; h=Content-Type:MIME-Version:Subject:From:Message-Id:Date:References: In-Reply-To:To:Cc; b=oPH9k4chNlHxH0cOIM1/Sxjlwnpmo+EbXdiJBeTCtigAIcq9D7QqSIZCty51v66t9gy8FDJ8wD+FBa/2DEgre5oogb9wXKU7FsPW/fAgC0ZQnyceM8pb8TSei/qatS5eWC/ANWvkFj0ysdNHeoJr9VzwYwPVH3vQJdFgsPuG9eg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Y2+LoeQW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Y2+LoeQW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09145C116C6; Fri, 27 Mar 2026 03:20:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774581628; bh=NMNqDhrPaal3Yltv8RJLavSk/i9ysKkz0fwPnx3hNL8=; h=Subject:From:Date:References:In-Reply-To:To:Cc:From; b=Y2+LoeQWsCDZA0zXQ7ruhPWgwkMRKNPKXe9mreuJvEQbHpG29Mq9RM43y4GEMC+pq JpdvMSxLpvF5VCr4HRpd8ms+3F4ZgadhTgXUceyi7DHtb8jRwPUExBRXVPT65BDJDR BTdjJTjVxc2mfqnbyvsVYZyc3BRi1tPSuMrPUdS74yhVppFjaP4LOiTqJ0X6qxMxPQ dKffPS/6g4vuAZN9aSoYf7wtKzK0jKq9TL02mHKdvAptSMm6c3Puhc73r0E6SCWTZN 3ijD/lmKlo0kUshCo1Rao/T/c/kpyRH6XXszPfEwXZZ0TRiWsGYZGGfx1DNz0sN+bN da8UEhhWHDF/Q== Received: from [10.30.226.235] (localhost [IPv6:::1]) by aws-us-west-2-korg-oddjob-rhel9-1.codeaurora.org (Postfix) with ESMTP id 7CFEC3809A0B; Fri, 27 Mar 2026 03:20:15 +0000 (UTC) Content-Type: text/plain; charset="utf-8" Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: Re: [PATCH net-next] virtio_net: sync RX buffer before reading the header From: patchwork-bot+netdevbpf@kernel.org Message-Id: <177458161428.3283168.99448398733931105.git-patchwork-notify@kernel.org> Date: Fri, 27 Mar 2026 03:20:14 +0000 References: In-Reply-To: To: Michael S. Tsirkin Cc: linux-kernel@vger.kernel.org, oelghoul@linux.ibm.com, sraithal@amd.com, jasowang@redhat.com, xuanzhuo@linux.alibaba.com, eperezma@redhat.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com, sdf@fomichev.me, vishs@meta.com, netdev@vger.kernel.org, virtualization@lists.linux.dev, bpf@vger.kernel.org Hello: This patch was applied to netdev/net-next.git (main) by Jakub Kicinski : On Tue, 24 Mar 2026 11:15:54 -0400 you wrote: > receive_buf() reads the virtio header through buf before > page_pool_dma_sync_for_cpu() runs in receive_small() or > receive_mergeable(). The header buffer is thus unsynchronized at the > point where flags and, for mergeable buffers, num_buffers are consumed. > > Omar Elghoul reported that on s390x Secure Execution this showed up as > greatly reduced virtio-net performance together with "bad gso" and > "bad csum" messages in dmesg. This is because with SE sync actually > copies data, so the header is uninitialized. > > [...] Here is the summary with links: - [net-next] virtio_net: sync RX buffer before reading the header https://git.kernel.org/netdev/net-next/c/fe3e54253f0b You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html