| From 5ff6bd6ff1f10e03d9dbb6006e7485bcfb591226 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Tue, 20 Apr 2021 01:54:04 -0300 |
| Subject: powerpc/pseries/iommu: Fix window size for direct mapping with pmem |
| |
| 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 |
| |