Re: [PATCH v8 00/23] efi/x86: Avoid bare metal decompressor during EFI boot

From: Borislav Petkov
Date: Sat Aug 05 2023 - 10:41:07 EST

On Wed, Aug 02, 2023 at 05:48:08PM +0200, Ard Biesheuvel wrote:
> Update the x86 boot path to avoid the bare metal decompressor when
> booting via the EFI stub. The bare metal decompressor inherits the
> loader's 1:1 mapping of DRAM when entering in 64-bit mode, and assumes
> that all of it is mapped read/write/execute, which will no longer be the
> case on systems built to comply with recently tightened logo
> requirements (*).
> Changes since v7 [10]:

My Zen1 box fails booting with those. It is related to memory encryption
because if I supply "mem_encrypt=off", it boots.

The failure is (typing it off from the video from the BMC):

/dev/root: Can't open blockdev
VFS: Cannot open root device "UUID=..."
Please append a correct "root=" boot option;

I'll bisect now but it is pretty clear which one is the culprit.