Re: [dpdk-dev] [PATCH] doc: Clarify IOMMU usage with "uio-pci" kernel module

["Tone Zhang (Arm Technology China)" <Tone.Zhang@arm.com>]

-----Original Message-----
From: Stephen Hemminger <stephen@networkplumber.org> 
Sent: Wednesday, September 5, 2018 5:22 PM
To: Tone Zhang (Arm Technology China) <Tone.Zhang@arm.com>
Cc: Rami Rosen <roszenrami@gmail.com>; dev@dpdk.org; nd <nd@arm.com>
Subject: Re: [dpdk-dev] [PATCH] doc: Clarify IOMMU usage with "uio-pci" kernel module

On Wed, 5 Sep 2018 00:20:29 +0000
"Tone Zhang (Arm Technology China)" <Tone.Zhang@arm.com> wrote:

> Hi Rami,
> 
> Yes, I mean “uio_pci_generic” kernel module.
> 
> I will update the change accordingly.
> 
> Thanks.
> 
> Br,
> Tone
> 
> From: Rami Rosen <roszenrami@gmail.com>
> Sent: Wednesday, September 5, 2018 3:55 AM
> To: Tone Zhang (Arm Technology China) <Tone.Zhang@arm.com>
> Cc: dev@dpdk.org; nd <nd@arm.com>
> Subject: Re: [dpdk-dev] [PATCH] doc: Clarify IOMMU usage with "uio-pci" kernel module
> 
> Hi Tone,
> >if the devices for used DPDK bound to the ``uio-pci`` kernel module, please make  
> 
> The three kernel modules which can be used for DPDK binding are vfio-pci, uio_pci_generic and igb_uio. Don't you mean here uio_pci_generic ?
> 
> Regards,
> Rami Rosen
> 
> 
> בתאריך יום ג׳, 4 בספט׳ 2018, 11:59, מאת tone.z
> When binding the devices used by DPDK to the "uio-pci" kernel module,
> the IOMMU should be disabled in order not to break the
> because of the virtual / physical address mapping.
> 
> The patch clarifies the IOMMU configuration on both x86_64 and arm64
> systems.
> 
> Signed-off-by: tone.zhang <tone.zhang@arm.com<mailto:tone.zhang@arm.com>>
> ---
>  doc/guides/linux_gsg/linux_drivers.rst | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/doc/guides/linux_gsg/linux_drivers.rst b/doc/guides/linux_gsg/linux_drivers.rst
> index 371a817..8f9ec8f 100644
> --- a/doc/guides/linux_gsg/linux_drivers.rst
> +++ b/doc/guides/linux_gsg/linux_drivers.rst
> @@ -48,6 +48,13 @@ be loaded as shown below:
>     ``vfio-pci``
> 2.7.4

Also, it would be good if documentation was clear in recommending using VFIO
instead if IOMMU is present.

Hi Stephen,

Yes, according to the description of the "UIO" and "VFIO" in the document, I believe that VFIO is recommended.

BTW, I have update the change to V3 (https://patches.dpdk.org/patch/44295/). Please have a review.

Thanks a lot!

Br,
Tone