Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [RFC PATCH v3 5/6] dt-bindings: of: Add restricted DMA pool | From | Florian Fainelli <> | Date | Thu, 7 Jan 2021 10:14:50 -0800 |
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On 1/7/21 10:00 AM, Konrad Rzeszutek Wilk wrote: >>> >>> >>> - Nothing stops the physical device from bypassing the SWIOTLB buffer. >>> That is if an errant device screwed up the length or DMA address, the >>> SWIOTLB would gladly do what the device told it do? >> >> So the system needs to provide a way to lock down the memory access, e.g. MPU. > > OK! Would it be prudent to have this in the description above perhaps?
Yes this is something that must be documented as a requirement for the restricted DMA pool users, otherwise attempting to do restricted DMA pool is no different than say, using a device private CMA region. Without the enforcement, this is just a best effort. -- Florian
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