DMA windows can only have a size of power of two on IODA2 hardware and
using memory_hotplug_max() to determine the upper limit won't work
correcly if it returns not power of two value.
This removes the check as the platform code does this check in
pnv_pci_ioda2_setup_default_config() anyway; the other client is VFIO
and that thing checks against locked_vm limit which prevents the userspace
from locking too much memory.
It is expected to impact DPDK on machines with non-power-of-two RAM size,
mostly. KVM guests are less likely to be affected as usually guests get
less than half of hosts RAM.
Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
---
Changes:
v2:
* instead of relaxing the check, this simply removes it
---
arch/powerpc/platforms/powernv/pci-ioda.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c
b/arch/powerpc/platforms/powernv/pci-ioda.c
index 1de94fb..433cf84 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -2776,7 +2776,7 @@ static long pnv_pci_ioda2_table_alloc_pages(int nid,
__u64 bus_offset,
if (!levels || (levels > POWERNV_IOMMU_MAX_LEVELS))
return -EINVAL;
- if ((window_size > memory_hotplug_max()) || !is_power_of_2(window_size))
+ if (!is_power_of_2(window_size))
return -EINVAL;
/* Adjust direct table size from window_size and levels */
--
2.11.0
