[PATCH 1/1] efi: stub: omit SetVirtualAddressMap() if marked unsupported in RT_PROP table

[Shawn Guo]

On Fri, Mar 05, 2021 at 10:39:58AM +0100, Ard Biesheuvel wrote:
> The EFI_RT_PROPERTIES_TABLE contains a mask of runtime services that are
> available after ExitBootServices(). This mostly does not concern the EFI
> stub at all, given that it runs before that. However, there is one call
> that is made at runtime, which is the call to SetVirtualAddressMap()
> (which is not even callable at boot time to begin with)
> 
> So add the missing handling of the RT_PROP table to ensure that we only
> call SetVirtualAddressMap() if it is not being advertised as unsupported
> by the firmware.
> 
> Signed-off-by: Ard Biesheuvel <ardb at kernel.org>

On Lenovo Yoga C630 laptop:

Tested-by: Shawn Guo <shawn.guo at linaro.org>

It's a great help to dropping 'efi=novamap' kernel cmdline, which is a
very nice thing for distros to support Snapdragon laptops.

Thanks much, Ard!

Shawn