Re: [RFC PATCH v2 11/20] mm: Access BOOT related data in the clear

[Tom Lendacky <thomas.lendacky@amd.com>]

On 09/12/2016 11:55 AM, Andy Lutomirski wrote:
> On Aug 22, 2016 6:53 PM, "Tom Lendacky" <thomas.lendacky@amd.com> wrote:
>>
>> BOOT data (such as EFI related data) is not encyrpted when the system is
>> booted and needs to be accessed as non-encrypted.  Add support to the
>> early_memremap API to identify the type of data being accessed so that
>> the proper encryption attribute can be applied.  Currently, two types
>> of data are defined, KERNEL_DATA and BOOT_DATA.
> 
> What happens when you memremap boot services data outside of early
> boot?  Matt just added code that does this.
> 
> IMO this API is not so great.  It scatters a specialized consideration
> all over the place.  Could early_memremap not look up the PA to figure
> out what to do?

Yes, I could see if the PA falls outside of the kernel usable area and,
if so, remove the memory encryption attribute from the mapping (for both
early_memremap and memremap).

Let me look into that, I would prefer something along that line over
this change.

Thanks,
Tom

> 
> --Andy
>