From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from new2-smtp.messagingengine.com (new2-smtp.messagingengine.com [66.111.4.224]) by dpdk.org (Postfix) with ESMTP id DC8671B2AE for ; Mon, 6 Nov 2017 13:00:54 +0100 (CET) Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailnew.nyi.internal (Postfix) with ESMTP id 526891069; Mon, 6 Nov 2017 07:00:54 -0500 (EST) Received: from frontend2 ([10.202.2.161]) by compute1.internal (MEProxy); Mon, 06 Nov 2017 07:00:54 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fridaylinux.org; h=cc:content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to:x-me-sender:x-me-sender:x-sasl-enc; s= fm1; bh=pkGXgDbE5/OVly7Z5NUWpordPCXBf8zWlqSV5rwxc7w=; b=dvaH9V5H bzQy+wkhKyciT/cfMvMP1lX/UcOzNiCfYPyP3Q6B9BwvXiZZbd3BKSYCgKETLGD7 iYnQp/lT+HTP6fkwyUP3wGWIfN9fs9nZLzR7Q3Ljel5uJFtqE4oT7zGyH0vupZ5x geWepkjPYuisy6q1c2WvzZvbdQVzdkJtS5uVkl+NUfLuXUTT02dvrGmrGEq9DmWQ dVqdynStNBmkne2xN8A8OY1LHmV/tiJZrlxirgxNYDiZJbP2dqQfGeORpkCTnh4b TcvkSXDQaneiOf0Soz7I3ArxrsjSVd4cMbZBoK3rK2qR5oltpmYV5s+tKh5LPg4w YBxtYyob3jRnzg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-sender :x-me-sender:x-sasl-enc; s=fm1; bh=pkGXgDbE5/OVly7Z5NUWpordPCXBf 8zWlqSV5rwxc7w=; b=FOpSSRbq2+GZp0hjLKqrahon7uAPfrcZpTTGSRturXYxY +TwJZ8E6cF9k4R3P8hFqKmsTKaArAi/NFfKUnVHDnLkT+KZl3y4LwZC1kl4YUIhB 8wSgIRiExkfeeY2n3/rOstlbP8zJK6H+AIFwlL8s8xc7qs+sacVSYln/BC3IgvLW aa5tJMo1NBBqavFXwXGg8KDVu+mnNyqy/wgGHGM+27MN+mAek4FMOI+syIliYD69 rjHkzOVOUfDTNqiF16Hn8WDZG0mGyDthvgHv/D0uu+Di581AGIwv9RPNDvc3IBg5 RiwwIE7UliwRFfe0kLK63HGUj8n8b2YZnxX1Kgb0w== X-ME-Sender: Received: from yliu-home (unknown [222.64.173.197]) by mail.messagingengine.com (Postfix) with ESMTPA id 78ADF242CF; Mon, 6 Nov 2017 07:00:50 -0500 (EST) Date: Mon, 6 Nov 2017 20:00:43 +0800 From: Yuanhan Liu To: Maxime Coquelin Cc: "Kavanagh, Mark B" , "dev@dpdk.org" , "Horton, Remy" , "Bie, Tiwei" , "mst@redhat.com" , "jfreiman@redhat.com" , "vkaplans@redhat.com" , "jasowang@redhat.com" , "Mcnamara, John" , "Loftus, Ciara" , "Stokes, Ian" , Thomas Monjalon Message-ID: <20171106120043.GE12931@yliu-home> References: <20171005083627.27828-1-maxime.coquelin@redhat.com> <20171005083627.27828-2-maxime.coquelin@redhat.com> <20171103130510.GB12931@yliu-home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Subject: Re: [dpdk-dev] [PATCH v3 01/19] Revert "vhost: workaround MQ fails to startup" X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 06 Nov 2017 12:00:55 -0000 On Fri, Nov 03, 2017 at 03:28:36PM +0100, Maxime Coquelin wrote: > > > On 11/03/2017 02:05 PM, Yuanhan Liu wrote: > >On Thu, Nov 02, 2017 at 10:40:26AM +0100, Maxime Coquelin wrote: > >>>Moving from QEMU v2.7.0 to v2.10.0 resolves the issue. However, herein lies the issue: QEMU v2.10.0 was only released in August of this year; anecdotally, we know that many OvS-DPDK customers use older versions of QEMU (typically, v2.7.0), and are likely un[able|willing] to move. With this patch, a hard dependency on QEMU v2.10 is created for users who want to use the vHU multiq feature in DPDK v17.11 (and subsequently, the upcoming OvS v2.9.0), which IMO will likely be unacceptable for many. > >> > >>Do you mean that upstream Qemu v2.7.0 is used in production? > >>I would expect the customers to use a distro Qemu which should contain > >>relevant fixes, or follow upstream's stable branches. > >> > >>FYI, Qemu v2.9.1 contains a backport of the fix. > >> > >>>One potential solution to this problem is to introduce a compile-time option that would allow the user to [dis|en]able the VHOST_USER_PROTOCOL_F_REPLY_ACK feature - is that something that would be acceptable to you Maxime? > >> > >>Yes, that's one option, but: > >>1. VHOST_USER_PROTOCOL_F_REPLY_ACK enabled should be the default > >>2. VHOST_USER_PROTOCOL_F_REPLY_ACK disabled will be less extensively > >>tested. > >> > >>Yuanhan, what do you think? > > > >My suggestion is to still disable it by default. Qemu 2.7 - 2.9 (inclusive) > >is a pretty big range, that I think quite many people would hit this issue > Ok, then what about adding a new flag to rte_vhost_driver_register(), as > done for tx zero copy to enable IOMMU feature? > If flag is unset, then we mask out both IOMMU virtio feature flag and > REPLY_ACK protocol feature flag. > > For a while this flag will be unset by default, not to break these > deprecated and unmaintained Qemu versions. But I think at some point > we should make it enabled by default, as it would be sad not to benefit > from this security feature. This sounds good to me. --yliu > > This change will have an impact on OVS, as it will need a new vhost-user > port option to enable IOMMU feature. Thing that is transparent to OVS > currently. > > Mark, Yuanhan, does that sound good to you? > > Maxime > > --yliu > >