Messages in this thread | | | Date | Thu, 5 Jan 2023 18:49:09 +0800 | From | Baolu Lu <> | Subject | Re: [RESEND PATCH v3] iommu/vt-d: Use passthrough mode for the Intel IPUs |
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On 2023/1/5 16:28, bingbu.cao@intel.com 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
Do you mind telling why does such DMA fault occur? How does the IPU driver map the fault address 76406000 ?
> As IPU is not an external facing device which is not risky, so use > IOMMU passthrough mode for Intel IPUs.
You can also set the passthrough mode with kernel option iommu=pt (globally) or by writing IDENTITY to
/sys/..path_to_device../iommu_group/type
(per-device).
> Fixes: 26f5689592e2 ("media: staging/intel-ipu3: mmu: Implement driver")
Please don't try to fix any problem in the device driver by adding any hard-coded quirky code in the IOMMU code.
> Signed-off-by: Bingbu Cao<bingbu.cao@intel.com>
-- Best regards, baolu
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