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

From	Matt Fleming <matt@codeblueprint.co.uk>
Newsgroups	linux.kernel
Subject	Re: [PATCH v5 17/32] x86/mm: Add support to access boot related data in the clear
Date	2017-05-18 22:00 +0200
Message-ID	<tIzKy-7VB-13@gated-at.bofh.it> (permalink)
References	<txTMB-1zl-13@gated-at.bofh.it> <tHt4t-3gB-19@gated-at.bofh.it> <tHt4t-3gB-17@gated-at.bofh.it>
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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().

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Re: [PATCH v5 17/32] x86/mm: Add support to access boot related data  in the clear Borislav Petkov <bp@alien8.de> - 2017-05-15 20:40 +0200
  Re: [PATCH v5 17/32] x86/mm: Add support to access boot related data  in the clear Borislav Petkov <bp@alien8.de> - 2017-05-18 11:10 +0200
    Re: [PATCH v5 17/32] x86/mm: Add support to access boot related data  in the clear Borislav Petkov <bp@alien8.de> - 2017-05-21 09:20 +0200
  Re: [PATCH v5 17/32] x86/mm: Add support to access boot related data  in the clear Matt Fleming <matt@codeblueprint.co.uk> - 2017-05-18 22:00 +0200

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