Re: [dpdk-dev] [PATCH 2/2] net: enable IOVA mode for PMDs

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

Hi Jianfeng,

On 10/11/2017 12:33 PM, Jianfeng Tan wrote:
> If we want to enable IOVA mode, introduced by
> commit 93878cf0255e ("eal: introduce helper API for IOVA mode"),
> we need PMDs (for PCI devices) to expose this flag.
> 
> Signed-off-by: Jianfeng Tan<jianfeng.tan@intel.com>
> ---
>   drivers/net/e1000/em_ethdev.c     | 3 ++-
>   drivers/net/e1000/igb_ethdev.c    | 5 +++--
>   drivers/net/fm10k/fm10k_ethdev.c  | 3 ++-
>   drivers/net/i40e/i40e_ethdev.c    | 3 ++-
>   drivers/net/i40e/i40e_ethdev_vf.c | 2 +-
>   drivers/net/ixgbe/ixgbe_ethdev.c  | 5 +++--
>   6 files changed, 13 insertions(+), 8 deletions(-)

This patch introduces a regression when doing device assignment in
guest, because current VT-d emulation only supports 39bits guest address
width [0].

In the Bz, Peter suggest we could have an IOVA allocator algorithm,
which could start to allocate IOVAs from 0. I think it could solve the
--no-huge case your series address, do you agree?

But it would be a long term solution, we need to fix this in stable.

Is the --no-huge option used in production, or is it only for testing?
If the latter do you think we could revert your patch while we find a
solution that makes all cases to work?

Ferruh, I see you also faced problems with KNI, how did you solved it?

Thanks,
Maxime

[0]: https://bugzilla.redhat.com/show_bug.cgi?id=1530957#c3