diff options
author | Alexey Kardashevskiy <aik@ozlabs.ru> | 2021-11-08 15:03:19 +1100 |
---|---|---|
committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-11-15 15:46:46 +1100 |
commit | ad3976025b311cdeb822ad3e7a7554018cb0f83f (patch) | |
tree | 75a1a9376f33b0093b371381c9865bcd863c4198 /arch/powerpc | |
parent | fb4ee2b30cd09e95524640149e4ee0d7f22c3e7b (diff) |
powerpc/pseries/ddw: Do not try direct mapping with persistent memory and one window
There is a possibility of having just one DMA window available with
a limited capacity which the existing code does not handle that well.
If the window is big enough for the system RAM but less than
MAX_PHYSMEM_BITS (which we want when persistent memory is present),
we create 1:1 window and leave persistent memory without DMA.
This disables 1:1 mapping entirely if there is persistent memory and
either:
- the huge DMA window does not cover the entire address space;
- the default DMA window is removed.
This relies on reverted 54fc3c681ded
("powerpc/pseries/ddw: Extend upper limit for huge DMA window for persistent memory")
to return the actual amount RAM in ddw_memory_hotplug_max() (posted
separately).
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211108040320.3857636-4-aik@ozlabs.ru
Diffstat (limited to 'arch/powerpc')
-rw-r--r-- | arch/powerpc/platforms/pseries/iommu.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c index 301fa5b3d528..8f998e55735b 100644 --- a/arch/powerpc/platforms/pseries/iommu.c +++ b/arch/powerpc/platforms/pseries/iommu.c @@ -1356,8 +1356,10 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn) len = order_base_2(query.largest_available_block << page_shift); win_name = DMA64_PROPNAME; } else { - direct_mapping = true; - win_name = DIRECT64_PROPNAME; + direct_mapping = !default_win_removed || + (len == MAX_PHYSMEM_BITS) || + (!pmem_present && (len == max_ram_len)); + win_name = direct_mapping ? DIRECT64_PROPNAME : DMA64_PROPNAME; } ret = create_ddw(dev, ddw_avail, &create, page_shift, len); |