[PATCH v2 10/10] ARM: p2v: reduce p2v alignment requirement to 2 MiB

[Nicolas Pitre]

On Tue, 22 Sep 2020, Ard Biesheuvel wrote:

> By changing the patchable sequences and the patching logic to carry
> more bits of offset, we can improve this: 11 bits gives us 4 GiB >> 11
> == 2 MiB granularity, and so you never waste more than that amount by
> rounding up the physical start of DRAM to the next multiple of 2 MiB.
> (Note that 2 MiB granularity guarantees that the linear mapping can be
> created efficiently, whereas less than 2 MiB may result in the linear
> mapping needing another level of page tables)

That is IMHO the top argument for limiting it to 2 MiB.
It would be worth making this explicit in the commit log.


Nicolas