[PATCH 5.11 544/601] powerpc/pseries/iommu: Fix window size for direct mapping with pmem

Greg Kroah-Hartman
2021-05-12T17:56:49Z

From: Leonardo Bras <leobras.c@gmail.com>

[ Upstream commit a9d2f9bb225fd2a764aef57738ab6c7f38d782ae ]

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: bf6e2d562bbc4 ("powerpc/dma: Fallback to dma_ops when persistent memory present")
Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210420045404.438735-1-leobras.c@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/platforms/pseries/iommu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 9fc5217f0c8e..836cbbe0ecc5 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -1229,7 +1229,7 @@ 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");
}
--
2.30.2