On Fri, Jan 8, 2021 at 2:15 AM Florian Fainelli <f.fainelli@xxxxxxxxx> wrote: > > 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. Will add in the next version. > -- > Florian
