From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: Yuanhan Liu <yliu@fridaylinux.org>,
Thomas Monjalon <thomas@monjalon.net>
Cc: "Kavanagh, Mark B" <mark.b.kavanagh@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>,
"Horton, Remy" <remy.horton@intel.com>,
"Bie, Tiwei" <tiwei.bie@intel.com>,
"mst@redhat.com" <mst@redhat.com>,
"jfreiman@redhat.com" <jfreiman@redhat.com>,
"vkaplans@redhat.com" <vkaplans@redhat.com>,
"jasowang@redhat.com" <jasowang@redhat.com>,
"Mcnamara, John" <john.mcnamara@intel.com>,
"Loftus, Ciara" <ciara.loftus@intel.com>,
"Stokes, Ian" <ian.stokes@intel.com>
Subject: Re: [dpdk-dev] [PATCH v3 01/19] Revert "vhost: workaround MQ fails to startup"
Date: Mon, 6 Nov 2017 13:50:35 +0100 [thread overview]
Message-ID: <d79764f2-cd0b-c2fa-02d9-66ea62345295@redhat.com> (raw)
In-Reply-To: <20171106122457.GG12931@yliu-home>
On 11/06/2017 01:24 PM, Yuanhan Liu wrote:
> On Mon, Nov 06, 2017 at 01:07:15PM +0100, Maxime Coquelin wrote:
>>
>>
>> On 11/06/2017 01:00 PM, Yuanhan Liu wrote:
>>> 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.
>>
>> Actually, I have posted a different patch, so that we don't have API
>> change for this. Upstream OVS can disable IOMMU feature, which will in
>> turn disable REPLY-ACK protocol feature if they want to.
>
> Sorry I missed that. So the REPLY-ACK will still be enabled by default and
> you leave the choice to the users to disable it, explicitly? This doesn't
> sound the best to me. We now know that it breaks OVS, but other users may
> hit the same issue again without any awareness.
>
> Also, I know this feature brings good benefits on security. But IIRC, you
> mentioned that it became barely un-usable with Linux kernel virtio-net
> driver.
>
> From the two points, I think let's make it be disable by default now?
What concerns me is that hasn't been replied yet is when will we
consider Qemu 2.7.0-Qemu v2.9.0 (Qemu v2.9.1 being fixed) old enough
to enable it by default? Knowing that Qemu 2.7.x/2.8.x are already
end of life uptream.
Maxime
> --yliu
>
next prev parent reply other threads:[~2017-11-06 12:50 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-05 8:36 [dpdk-dev] [PATCH v3 00/19] Vhost-user: Implement device IOTLB support Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 01/19] Revert "vhost: workaround MQ fails to startup" Maxime Coquelin
2017-11-01 17:11 ` Kavanagh, Mark B
2017-11-02 9:40 ` Maxime Coquelin
2017-11-03 13:05 ` Yuanhan Liu
2017-11-03 14:28 ` Maxime Coquelin
2017-11-06 12:00 ` Yuanhan Liu
2017-11-06 12:07 ` Maxime Coquelin
2017-11-06 12:24 ` Yuanhan Liu
2017-11-06 12:50 ` Maxime Coquelin [this message]
2017-11-06 13:36 ` Yuanhan Liu
2017-11-03 15:34 ` Thomas Monjalon
2017-11-03 16:31 ` Kavanagh, Mark B
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 02/19] vhost: make error handling consistent in rx path Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 03/19] vhost: prepare send_vhost_message() to slave requests Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 04/19] vhost: add support to slave requests channel Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 05/19] vhost: declare missing IOMMU-related definitions for old kernels Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 06/19] vhost: add iotlb helper functions Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 07/19] vhost: iotlb: add pending miss request list and helpers Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 08/19] vhost-user: add support to IOTLB miss slave requests Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 09/19] vhost: initialize vrings IOTLB caches Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 10/19] vhost-user: handle IOTLB update and invalidate requests Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 11/19] vhost: introduce guest IOVA to backend VA helper Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 12/19] vhost: use the guest IOVA to host " Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 13/19] vhost: enable rings at the right time Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 14/19] vhost: don't dereference invalid dev pointer after its reallocation Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 15/19] vhost: postpone rings addresses translation Maxime Coquelin
2017-10-13 1:47 ` Yao, Lei A
2017-10-13 7:32 ` Maxime Coquelin
2017-10-13 7:55 ` Yao, Lei A
2017-10-13 7:56 ` Maxime Coquelin
2017-10-16 5:59 ` Yao, Lei A
2017-10-16 6:23 ` Yao, Lei A
2017-10-16 9:47 ` Maxime Coquelin
2017-10-16 10:47 ` Maxime Coquelin
2017-10-17 1:24 ` Yao, Lei A
2017-10-17 8:06 ` Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 16/19] vhost-user: translate ring addresses when IOMMU enabled Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 17/19] vhost-user: iommu: postpone device creation until ring are mapped Maxime Coquelin
2017-11-02 7:21 ` Yao, Lei A
2017-11-02 8:21 ` Maxime Coquelin
2017-11-02 16:02 ` Maxime Coquelin
2017-11-03 8:25 ` Maxime Coquelin
2017-11-03 15:15 ` Michael S. Tsirkin
2017-11-03 15:54 ` Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 18/19] vhost: iommu: Invalidate vring in case of matching IOTLB invalidate Maxime Coquelin
2017-10-05 8:36 ` [dpdk-dev] [PATCH v3 19/19] vhost: enable IOMMU support Maxime Coquelin
2017-10-06 6:24 ` [dpdk-dev] [PATCH v3 00/19] Vhost-user: Implement device IOTLB support Yuanhan Liu
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