Re: [SeaBIOS] [RFC 2/3] Transitions to and from 64 bits

[Gerd Hoffmann]

Hi,
> +/****************************************************************
> Page table
> ****************************************************************/
>
> +void *gen_identity_page_table(u64 max_addr)
> +{
> /* Map directly all the addresses */
> u32 pt_entries = (max_addr + 0xFFF) >> 12;
> u32 pdt_entries = (pt_entries + 0x1FF) >> 9;
> u32 pdpt_entries = (pdt_entries + 0x1FF) >> 9;
> u32 pml4_entries = (pdpt_entries + 0x1FF) >> 9;

You can use hugepages.  Then you'll need _alot_ less memory for the
pagetables, and the copying probably goes faster too.

You might consider mapping the nvdimm below 4G instead of entering long
mode.

cheers,
  Gerd