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Alexey Kardashevskiy authored
Unlike normal memory ("memory" compatible type in the FDT), the persistent memory ("ibm,pmemory" in the FDT) can be mapped anywhere in the guest physical space and it can be used for DMA. In order to maintain 1:1 mapping via the huge DMA window, we need to know the maximum physical address at the time of the window setup. So far we've been looking at "memory" nodes but "ibm,pmemory" does not have fixed addresses and the persistent memory may be mapped afterwards. Since the persistent memory is still backed with page structs, use MAX_PHYSMEM_BITS as the upper limit. This effectively disables huge DMA window in LPAR under pHyp if persistent memory is present but this is the best we can do for the moment. Signed-off-by:
Alexey Kardashevskiy <aik@ozlabs.ru> Tested-by: Wen Xiong<wenxiong@linux.vnet.ibm.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200331012338.23773-1-aik@ozlabs.ru
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