Re: [PATCH] efistub/tpm: Use ACPI reclaim memory for event log to avoid corruption

[Jiri Slaby <jirislaby@kernel.org>]

On 25. 10. 24, 9:30, Ard Biesheuvel wrote:
> To me, it seems like the use of EFI_ACPI_RECLAIM_MEMORY in this case
> simply tickles a bug in the firmware that causes it to corrupt the
> memory attributes table. The fact that cold boot behaves differently
> is a strong indicator here.
> 
> I didn't see the results of the memory attribute table dumps on the
> bugzilla thread, but dumping this table from EFI is not very useful
> because it will get regenerated/updated at ExitBootServices() time.
> Unfortunately, that also takes away the console so capturing the state
> of that table before the EFI stub boots the kernel is not an easy
> thing to do.
> 
> Is the memattr table completely corrupted? It also has a version
> field, and only versions 1 and 2 are defined so we might use that to
> detect corruption.

So from a today test:
https://bugzilla.suse.com/attachment.cgi?id=878296

 > efi: memattr: efi_memattr_init: tab=0x7752f018 ver=1 
size=16+2*1705287680=0x00000000cb494010

version is NOT corrupted :).

thanks,
-- 
js
suse labs