RE: [PATCH] x86/efi: Don't unmap EFI boot services code/data regions for EFI_OLD_MEMMAP and EFI_MIXED_MODE

From: Prakhya, Sai Praneeth
Date: Fri Dec 28 2018 - 16:28:17 EST

> > Acked-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> >
> > with the sidenote that I won't be able to test this myself until
> > monday at the earliest.
> OK, so I have tested both efi=old_map and mixed mode before and after
> applying this patch, using QEMU/KVM with 64-bit and 32-bit builds of OVMF
> [respectively]
> efi=old_map is indeed broken before and needs this patch.
> Mixed mode works just fine both before and after applying the patch, but I
> suggest we keep this patch as-is and address mixed mode later if needed (I
> spotted a couple of things in the boot log that may need some attention but I'm
> not sure if the issue is in Linux or in OVMF)

Thanks for testing this Ard.

For testing Mixed mode, I have used QEMU/KVM with 64-bit and 32-bit OVMF
and mixed mode is broken for me without this patch.

I am using an older OVMF build and probably that might be the reason for us seeing
different behaviors. Also, kernel config file might have some role to play.. I guess.