[dpdk-dev,01/21] Revert "vhost: workaround MQ fails to startup"

  This reverts commit 04d81227960b5c1cf2f11f492100979ead20c526.

As agreed when this workaround was introduced, it can be reverted
as Qemu v2.10 that fixes the issue is now out.

The reply-ack feature is required for vhost-user IOMMU support.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 lib/librte_vhost/vhost_user.h | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)
  

On Thu, Aug 31, 2017 at 11:50:03AM +0200, Maxime Coquelin wrote:
> This reverts commit 04d81227960b5c1cf2f11f492100979ead20c526.
> 
> As agreed when this workaround was introduced, it can be reverted
> as Qemu v2.10 that fixes the issue is now out.

First of all, I'm very sorry for being so late on review!

I didn't quite remember we have come an agreement on that. I think my
old concern still counts: how do you handle the combo like DPDK v17.11
and QEMU v2.7-2.9 (assume we take this patch in DPDK v17.11) ?

Note that it's not a trivial bug, it's a fatal bug that freezes QEMU,
IIRC.

	--yliu

> The reply-ack feature is required for vhost-user IOMMU support.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
  

Hi Yuanhan,

On 09/07/2017 01:54 PM, Yuanhan Liu wrote:
> On Thu, Aug 31, 2017 at 11:50:03AM +0200, Maxime Coquelin wrote:
>> This reverts commit 04d81227960b5c1cf2f11f492100979ead20c526.
>>
>> As agreed when this workaround was introduced, it can be reverted
>> as Qemu v2.10 that fixes the issue is now out.
> 
> First of all, I'm very sorry for being so late on review!
> 
> I didn't quite remember we have come an agreement on that. 


> I think my
> old concern still counts: how do you handle the combo like DPDK v17.11
> and QEMU v2.7-2.9 (assume we take this patch in DPDK v17.11) ?
> 
> Note that it's not a trivial bug, it's a fatal bug that freezes QEMU,
> IIRC
IIRC, I also raised the concern initially but after having listed the
possible solutions, I thought we agreed there were no trivial way to
detect the bug in Qemu and so we would re-enable it once upstream Qemu
got fixed.

Note that we're talking about upstream here, which should not be used in
production. Distro's Qemu v2.7/v2.9 should be fixed, as RHEL-7.4 has been.

Any thougths?

Maxime

> 	--yliu
> 
>> The reply-ack feature is required for vhost-user IOMMU support.
>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
  

On 09/07/2017 02:59 PM, Maxime Coquelin wrote:
> Hi Yuanhan,
> 
> On 09/07/2017 01:54 PM, Yuanhan Liu wrote:
>> On Thu, Aug 31, 2017 at 11:50:03AM +0200, Maxime Coquelin wrote:
>>> This reverts commit 04d81227960b5c1cf2f11f492100979ead20c526.
>>>
>>> As agreed when this workaround was introduced, it can be reverted
>>> as Qemu v2.10 that fixes the issue is now out.
>>
>> First of all, I'm very sorry for being so late on review!
>>
>> I didn't quite remember we have come an agreement on that. 
> 
> 
>> I think my
>> old concern still counts: how do you handle the combo like DPDK v17.11
>> and QEMU v2.7-2.9 (assume we take this patch in DPDK v17.11) ?
>>
>> Note that it's not a trivial bug, it's a fatal bug that freezes QEMU,
>> IIRC
> IIRC, I also raised the concern initially but after having listed the
> possible solutions, I thought we agreed there were no trivial way to
> detect the bug in Qemu and so we would re-enable it once upstream Qemu
> got fixed.
> 
> Note that we're talking about upstream here, which should not be used in
> production. Distro's Qemu v2.7/v2.9 should be fixed, as RHEL-7.4 has been.
> 
> Any thougths?

Actually, stable v2.9.1 contains the fix, so only v2.7 and v2.8 are
impacted.

This is a good news, however it prevents to detect vulnerable Qemu
versions based on new features bit introduced in v2.10.

Maxime
> Maxime
> 
>>     --yliu
>>
>>> The reply-ack feature is required for vhost-user IOMMU support.
>>>
>>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>