Re: [PATCH v5 17/32] x86/mm: Add support to access boot related data in the clear

Matt Fleming
2017-05-18T19:51:00Z

On Mon, 15 May, at 08:35:17PM, Borislav Petkov wrote:
> On Tue, Apr 18, 2017 at 04:19:21PM -0500, Tom Lendacky wrote:
>
> > + paddr = boot_params.efi_info.efi_memmap_hi;
> > + paddr <<= 32;
> > + paddr |= boot_params.efi_info.efi_memmap;
> > + if (phys_addr == paddr)
> > + return true;
> > +
> > + paddr = boot_params.efi_info.efi_systab_hi;
> > + paddr <<= 32;
> > + paddr |= boot_params.efi_info.efi_systab;
>
> So those two above look like could be two global vars which are
> initialized somewhere in the EFI init path:
>
> efi_memmap_phys and efi_systab_phys or so.
>
> Matt ?
>
> And then you won't need to create that paddr each time on the fly. I
> mean, it's not a lot of instructions but still...

We should already have the physical memmap address available in
'efi.memmap.phys_map'.

And the physical address of the system table should be in
'efi_phys.systab'. See efi_init().