Messages in this thread | | | Date | Fri, 25 Jun 2021 15:18:58 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH v2 0/3] iommu: Enable non-strict DMA on QCom SD/MMC |
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Hi Douglas,
On Thu, Jun 24, 2021 at 10:17:56AM -0700, Douglas Anderson wrote: > The goal of this patch series is to get better SD/MMC performance on > Qualcomm eMMC controllers and in generally nudge us forward on the > path of allowing some devices to be in strict mode and others to be in > non-strict mode.
So if I understand it right, this patch-set wants a per-device decision about setting dma-mode to strict vs. non-strict.
I think we should get to the reason why strict mode is used by default first. Is the default on ARM platforms to use iommu-strict mode by default and if so, why?
The x86 IOMMUs use non-strict mode by default (yes, it is a security trade-off).
Regards,
Joerg
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