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 relaxes the check by rounding up the value returned by memory_hotplug_max(). 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> --- arch/powerpc/platforms/powernv/pci-ioda.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c index 269f119e4b3c..4c62162da181 100644 --- a/arch/powerpc/platforms/powernv/pci-ioda.c +++ b/arch/powerpc/platforms/powernv/pci-ioda.c @@ -2769,7 +2769,8 @@ 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 ((window_size > roundup_pow_of_two(memory_hotplug_max())) || + !is_power_of_2(window_size)) return -EINVAL; /* Adjust direct table size from window_size and levels */ -- 2.11.0