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From: Ferruh Yigit <ferruh.yigit@intel.com>
To: Alejandro Lucero <alejandro.lucero@netronome.com>, dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH] igb_uio: map dummy dma forcing iommu domain attachment
Date: Tue, 7 Feb 2017 15:59:20 +0000	[thread overview]
Message-ID: <67a9fd3b-b7f5-c641-9f59-590155cbd30b@intel.com> (raw)
In-Reply-To: <1484742475-41005-1-git-send-email-alejandro.lucero@netronome.com>

Hi Alejandro,

On 1/18/2017 12:27 PM, Alejandro Lucero wrote:
> For using a DPDK app when iommu is enabled, it requires to
> add iommu=pt to the kernel command line. But using igb_uio driver
> makes DMAR errors because the device has not an IOMMU domain.

Please help to understand the scope of the problem,

1- How can you re-produce the problem?

2- What happens get DMAR errors, is it prevents device work or some
annoying error messages?

3- Can you please share the error messages?


> 
> Since kernel 3.15, iommu=pt requires to use the internal kernel
> DMA API for attaching the device to the IOMMU 1:1 mapping, aka
> si_domain. Previous versions did attach the device to that
> domain when intel iommu notifier was called.

Again, what is not working since 3.15?

> 
> This is not a problem if the driver does later some call to the
> DMA API because the mapping can be done then. But DPDK apps do
> not use that DMA API at all.

Is this same/similar with: http://dpdk.org/dev/patchwork/patch/12654/

> 
> Doing this dma map and unmap is harmless even when iommu is not
> enabled at all.
> 
> Signed-off-by: Alejandro Lucero <alejandro.lucero@netronome.com>
<...>

Thanks,
ferruh

next prev parent reply	other threads:[~2017-02-07 15:59 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-18 12:27 Alejandro Lucero
2017-02-07 15:59 ` Ferruh Yigit [this message]
2017-02-08 11:54   ` Alejandro Lucero
2017-02-10 19:03     ` Ferruh Yigit
2017-02-10 19:06       ` Ferruh Yigit
2017-02-13 13:38         ` Alejandro Lucero
2017-02-13 15:54           ` Ferruh Yigit
2017-02-13 13:31       ` Alejandro Lucero
2017-02-17 12:29 ` Ferruh Yigit
2017-03-30 20:20   ` Thomas Monjalon

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