Re: [PATCH v2 0/3] vhost: disable iommu support by default

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 11/07/2017 12:25 PM, Kevin Traynor wrote:
> On 11/07/2017 10:56 AM, Kavanagh, Mark B wrote:
>>> From: Maxime Coquelin [mailto:maxime.coquelin@redhat.com]
>>> Sent: Monday, November 6, 2017 8:38 PM
>>> To: dev@dpdk.org; yliu@fridaylinux.org; Kavanagh, Mark B
>>> <mark.b.kavanagh@intel.com>; thomas@monjalon.net; ktraynor@redhat.com
>>> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
>>> Subject: [PATCH v2 0/3] vhost: disable iommu support by default
>>>
>>> This series disables IOMMU feature by default, and introduce
>>> a new flag passed at vhost device registration time to enable
>>> it explicitly.
>>>
>>> When disabled, patch 1 also disables reply-ack protocol feature
>>> to avoid Qemu v2.7.0-v2.9.0 reply-ack bug with multiqueue.
>>>
>>> Last patch adds a Vhost PMD "iommu-support" parameter to enable
>>> the IOMMU feature.
>>

Hi Kevin,

> Hi Maxime - OVS-DPDK does not use the vhost pmd, so that means that
> iommu could not be used with OVS-DPDK at present. Did I get that right?

No :)

This is supported both with and without using Vhost PMD.

When using the Vhost lib directly, you just have to pass
RTE_VHOST_USER_IOMMU_SUPPORT flag to rte_vhost_driver_register(),
this is patch 1.

When using Vhost PMD, passing the iommu-support=1 option to the vdev
cmdline will set this flag, this is patch 2.

Thanks,
Maxime

> Ciara proposed patches for vhost pmd in OVS-DPDK but it is quite an
> intrusive change and has been postponed multiple times due to various
> issues.
>
> thanks,
> Kevin.
> 
>> Hi Maxime,
>>
>> I'm happy to confirm that this patchset resolves the vhost user mutltiq issue for OvS-DPDK, with QEMU v2.7.1.
>>
>> Additionally, all of the individual patches look good - thanks for all of your efforts on this!
>>
>> Tested-by: Mark Kavanagh <mark.b.kavanagh@intel.com>
>> Acked-by: Mark Kavanagh <mark.b.kavanagh@intel.com>
>>
>> Cheers,
>> Mark
>>
>>>
>>> Maxime Coquelin (3):
>>>   vhost: disable reply-ack protocol feature if iommu feature disabled
>>>   vhost: add flag to enable iommu support
>>>   net: vhost: add iommu-support parameter to enable IOMMU feature
>>>
>>> doc/guides/nics/vhost.rst              |  5 +++++
>>> doc/guides/prog_guide/vhost_lib.rst    | 14 ++++++++++++++
>>> doc/guides/rel_notes/release_17_11.rst |  3 ++-
>>> drivers/net/vhost/rte_eth_vhost.c      | 13 +++++++++++++
>>> lib/librte_vhost/rte_vhost.h           |  1 +
>>> lib/librte_vhost/socket.c              |  6 ++++++
>>> lib/librte_vhost/vhost_user.c          | 24 ++++++++++++++++++++++--
>>> 7 files changed, 63 insertions(+), 3 deletions(-)
>>>
>>> --
>>> 2.13.6
>>
>