Re: [RESEND v2] iommu/vt-d: Use passthrough mode for the Intel IPUs

From: Andy Shevchenko
Date: Tue Apr 20 2021 - 06:20:50 EST


On Tue, Apr 20, 2021 at 10:48:33AM +0800, Bingbu Cao wrote:
> Intel IPU(Image Processing Unit) has its own (IO)MMU hardware,
> The IPU driver allocates its own page table that is not mapped
> via the DMA, and thus the Intel IOMMU driver blocks access giving
> this error:
>
> DMAR: DRHD: handling fault status reg 3
> DMAR: [DMA Read] Request device [00:05.0] PASID ffffffff
> fault addr 76406000 [fault reason 06] PTE Read access is not set
>
> As IPU is not an external facing device which is not risky, so use
> IOMMU passthrough mode for Intel IPUs.
>
> Fixes: 26f5689592e2 ("media: staging/intel-ipu3: mmu: Implement driver")
> Signed-off-by: Bingbu Cao <bingbu.cao@xxxxxxxxx>
> ---
> drivers/iommu/intel/iommu.c | 29 +++++++++++++++++++++++++++++

This misses the changelog from v1 followed by the explanation why resent.

--
With Best Regards,
Andy Shevchenko