From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 150815490D for ; Thu, 22 Feb 2024 20:02:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708632172; cv=none; b=Ug2VZ01qInUDJG0dyXO18/LE/GGxSuTC/PXhnXZ6E2W9mxTREW6vfEH98nl4DPqbrZhVkTD8YfvdpeO5SoBboinzHTIgG1XDz6z8ymGcdk5RhLdljepDdTmO/RdWMWrHYH/YX0S8BCLJCJa5DZMdzd8+9w3P3qUiJKIp8vraCLQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708632172; c=relaxed/simple; bh=aknFNqqxJry03mMtGqJFoI/wKDCcG2OQaTtQxGeRRpc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: In-Reply-To:Content-Type:Content-Disposition; b=hHncKdrEKr0rFUeyke7+upSXGKFd1jGsmff9AosIZiRaWTuorej1fA6+2cA3X8PhRHMFoJp2jzhE4f+AVIzycbet7kbImawVLhNqJK3pboFweezKkb4mIdSyzaAZ7sVESsBK2pyRNpudWslwiOArvnUEuydLyaI1mus76XTN6e8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none 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=JkIc6wGO; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none 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="JkIc6wGO" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1708632169; 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=Ip/bb26cz2+ipekHalCr5lDscUM2updhLQwbQoyojpM=; b=JkIc6wGOdNyvV00ujFj0cthtQh/iN5Agz5lEUFva0BE+e6EMpkNqtRC2Ep2lwBx15vJp7G weSRGjLjsWF/XCvROCOtpzJ1+bQeUp++KgWKReyWAGhdPvHwBiBm72IkeHnUoK7Wa+fiXi AHak35FxlvlFt4DvLQ+iFL0fjQG89Us= Received: from mail-wm1-f72.google.com (mail-wm1-f72.google.com [209.85.128.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-689-K6Cpy4-bOkiX_SODqi1B-g-1; Thu, 22 Feb 2024 15:02:48 -0500 X-MC-Unique: K6Cpy4-bOkiX_SODqi1B-g-1 Received: by mail-wm1-f72.google.com with SMTP id 5b1f17b1804b1-411dca63c56so413615e9.1 for ; Thu, 22 Feb 2024 12:02:48 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1708632167; x=1709236967; 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=Ip/bb26cz2+ipekHalCr5lDscUM2updhLQwbQoyojpM=; b=DgfvwbjHmhFchIAa8SgMcuURfBm5XDdduiXa+Hz7P3+vlBTE8uJK5sfPtN7nnkRDa6 2hHJy9d1WrMR9ciGRl3Nr//53hj3LanSP5imksWKmxqalG6LnBD3eHKOhX6BeAHLYLM6 zp6aKSAHPdPhQCGvQWethvspD86yHFbQTBh8ZKuGYQuWX6VSs+z3hlhE5M9chpzGtHN5 AUY5j/X1+IAMLIaVevkVUCikX2OyCSRFEfogUsLWc7syKVDgXgnpHIoNjrfN7xw2Wvl2 /VFNPhkbQxbRlQVtE3f5/WIME6s6niYqEmdc1nmewZfSr7Id45cs0+SBEC0Nnpa9sr4z cpYQ== X-Forwarded-Encrypted: i=1; AJvYcCXFVIyo8MnxMC5//HOp4ic/sb1KrQiU2X8kZHrv4MrekWl61twhBsL3E//W1eS3A+aD2xb24NIOeT+IwVbJ2V1DwrrPGS7AN2L5akr6Z68= X-Gm-Message-State: AOJu0YytzhdTkHBbTc0wizjlXOBog5slmEF0qYVm3mLn7Hlx1bD7PqXa N+lNGuFDZ1Sjsp86Yxjm/izp5KDqhKCsTKnyAeJk0r3DPkQNq203+FlvyTL3FUbxcHZzLvYuwqS zQddHkQOChChkJEy81xm3HcOUlbiIqWDHjxqJ7t0LKygeoJkpVUROqiJOyIX+8h1TPtmjbIeT1n k= X-Received: by 2002:a5d:480d:0:b0:33d:9d4a:b28 with SMTP id l13-20020a5d480d000000b0033d9d4a0b28mr114021wrq.18.1708632167122; Thu, 22 Feb 2024 12:02:47 -0800 (PST) X-Google-Smtp-Source: AGHT+IFGY5xEB+oirt/8WYolwR+t/b3r7Lw8iYBr645QsLpjupov8MKzMLmF73APkFMsTjyAiTEk6A== X-Received: by 2002:a5d:480d:0:b0:33d:9d4a:b28 with SMTP id l13-20020a5d480d000000b0033d9d4a0b28mr114007wrq.18.1708632166787; Thu, 22 Feb 2024 12:02:46 -0800 (PST) Received: from redhat.com ([172.93.237.99]) by smtp.gmail.com with ESMTPSA id bi21-20020a05600c3d9500b004128808db91sm3049224wmb.23.2024.02.22.12.02.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Feb 2024 12:02:46 -0800 (PST) Date: Thu, 22 Feb 2024 15:02:39 -0500 From: "Michael S. Tsirkin" To: Andrew Melnychenko Cc: jasowang@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, yuri.benditovich@daynix.com, yan@daynix.com Subject: Re: [PATCH 1/1] vhost: Added pad cleanup if vnet_hdr is not present. Message-ID: <20240222150212-mutt-send-email-mst@kernel.org> References: <20240115194840.1183077-1-andrew@daynix.com> <20240115172837-mutt-send-email-mst@kernel.org> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20240115172837-mutt-send-email-mst@kernel.org> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Jan 15, 2024 at 05:32:25PM -0500, Michael S. Tsirkin wrote: > On Mon, Jan 15, 2024 at 09:48:40PM +0200, Andrew Melnychenko wrote: > > When the Qemu launched with vhost but without tap vnet_hdr, > > vhost tries to copy vnet_hdr from socket iter with size 0 > > to the page that may contain some trash. > > That trash can be interpreted as unpredictable values for > > vnet_hdr. > > That leads to dropping some packets and in some cases to > > stalling vhost routine when the vhost_net tries to process > > packets and fails in a loop. > > > > Qemu options: > > -netdev tap,vhost=on,vnet_hdr=off,... > > > > Signed-off-by: Andrew Melnychenko > > --- > > drivers/vhost/net.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c > > index f2ed7167c848..57411ac2d08b 100644 > > --- a/drivers/vhost/net.c > > +++ b/drivers/vhost/net.c > > @@ -735,6 +735,9 @@ static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq, > > hdr = buf; > > gso = &hdr->gso; > > > > + if (!sock_hlen) > > + memset(buf, 0, pad); > > + > > if ((gso->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && > > vhost16_to_cpu(vq, gso->csum_start) + > > vhost16_to_cpu(vq, gso->csum_offset) + 2 > > > > Hmm need to analyse it to make sure there are no cases where we leak > some data to guest here in case where sock_hlen is set ... Could you post this analysis pls? > > -- > > 2.43.0