Re: [PATCH -v2 0/4] EFI 1:1 mapping

Matthew Garrett
2013-06-19T16:21:23Z

On Wed, Jun 19, 2013 at 06:18:27PM +0200, Borislav Petkov wrote:
> On Wed, Jun 19, 2013 at 05:08:04PM +0100, Matthew Garrett wrote:
> > But, as always, the only reliable thing to do here is to behave as
> > much like Windows as possible. Which means performing the 1:1 mapping
> > but maintaining the high mapping, and passing the high values via
> > SetVirtualAddressMap.
>
> We can't pass the high values via SetVirtualAddressMap and have EFI
> runtime in the kexec-ed kernel, as you and I established last week. And
> since not all would want EFI runtime in the kexec-ed kernel, I'm leaning
> more towards a boot-time option which enables the 1:1 mapping.

Yes, kexec needs a different solution.

> Btw, why would you even want the 1:1 mappings if we pass the high values
> via SetVirtualAddressMap?

Because firmware images don't always update all of the pointers, and so
will crash if the 1:1 mappings aren't present.

--
Matthew Garrett | mjg59@srcf.ucam.org