Commit a9d2f9bb authored by Leonardo Bras's avatar Leonardo Bras Committed by Michael Ellerman
Browse files

powerpc/pseries/iommu: Fix window size for direct mapping with pmem 



As of today, if the DDW is big enough to fit (1 << MAX_PHYSMEM_BITS)
it's possible to use direct DMA mapping even with pmem region.

But, if that happens, the window size (len) is set to (MAX_PHYSMEM_BITS
- page_shift) instead of MAX_PHYSMEM_BITS, causing a pagesize times
smaller DDW to be created, being insufficient for correct usage.

Fix this so the correct window size is used in this case.

Fixes: bf6e2d56 ("powerpc/dma: Fallback to dma_ops when persistent memory present")
Signed-off-by: default avatarLeonardo Bras <leobras.c@gmail.com>
Reviewed-by: default avatarAlexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210420045404.438735-1-leobras.c@gmail.com
parent e4e8bc1d

arch/powerpc/platforms/pseries/iommu.c

+1 −1
Original line number Diff line number Diff line
@@ -1252,7 +1252,7 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn) 
	if (pmem_present) {

		if (query.largest_available_block >=

		    (1ULL << (MAX_PHYSMEM_BITS - page_shift)))

			len = MAX_PHYSMEM_BITS - page_shift;

			len = MAX_PHYSMEM_BITS;

		else

			dev_info(&dev->dev, "Skipping ibm,pmemory");

	}