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If not, how in the world is the OS supposed to = know > these memory ranges are _not_ for general use? I feel like there is > something missing here... > Maybe I am miss understanding something here , but if BIOS/UEFI will reserv= e this pages=20 They will be "out of kernel" which will work for propriety driver but this = memory will not=20 be useable for generic driver which will attempt to pin this memory with ge= t_user_pages() . so we can go and try to fix that (not sure this is the right way) . another option here is to use some kernel infrastructure which from one s= ide reserve the memory from general use on the other hand kernel will be aware of this pages so get_user_pages() w= ill work on this memory . from what we saw CMA infrastructure can support such requirements. Please let me know if you think I missing here something . Thanks , and sorry for format mess . > thanks, >=20 > greg k-h