Re: [PATCH v2] x86/mm/KASLR: EFI region is mistakenly included into KASLR VA space for randomization

[Ard Biesheuvel]

On 24 March 2017 at 09:40, Borislav Petkov <bp@xxxxxxxxx> wrote:
> On Fri, Mar 24, 2017 at 09:37:36AM +0000, Ard Biesheuvel wrote:
>> No. It is the firmware's EFI code, and the virtual translation applied
>> by the OS is made known to the firmware by means of a call into the
>> runtime service SetVirtualAddressMap().
>
> We can still randomize within those 64G before calling
> SetVirtualAddressMap(). The question is, do we want to or need to, even?
>

That is a different matter. If the regions are only mapped while
runtime services invocations are in progress (as we do on ARM), I am
not sure if it matters that much, given how rarely that occurs in
normal use.