On Thu, 06 Aug 2026 15:50:27 -0500, Gaurav Batra wrote:
> In powerPC, if Dynamic DMA Window is big enough, RAM is pre-mapped. To
> determine the size of RAM, a PAPR+ property "ibm,lrdr-capacity" is used.
> This OF property dictates what is the max size of RAM an LPAR can have,
> including DR added memory.
>
> In PowerPC, 16GB pages can be allocated at machine level and then
> assigned to LPARs. These 16GB pages are added to LPAR memory at the time
> of boot. The address range for these 16GB pages is above MAX RAM an LPAR
> can have (ibm,lrdr-capacity). In the current implementation, these 16GB
> pages are being excluded from pre-mapped TCEs. A driver can have DMA
> buffers allocated from 16GB pages. This results in platform to raise an
> EEH when DMA is attempted on buffers in 16GB memory range.
>
> [...]
Applied to powerpc/next.
[1/1] powerpc/pseries/iommu: Add TCEs for 16GB pages when RAM is pre-mapped
https://git.kernel.org/powerpc/c/0b8b0c17a8998709ecb2852d56442ea981102941
cheers
