Re: [PATCH v2 3/3] x86/efi: Add opt-out mechanism for BGRT preservation

[Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>]

On Tue, Mar 10, 2026 at 12:41:40PM +0100, Jan Beulich wrote:
> On 06.03.2026 14:29, Soumyajyotii Ssarkar wrote:
> > As described in the task, BGRT preservation is now enabled by default to 
> > fix ACPI corruption
> > for desktop/workstation systems (similar to ESRT).
> 
> What's "the task"?

I asked him to work on this, but I don't think there is a gitlab issue
created, so reference to "the task" is not relevant here.

> > Add an opt-out parameter 'efi=no-bgrt' to allow disabling BGRT
> > preservation on systems where the ~1MB memory overhead is not
> > desired.
> 
> This looks to contradict ...
> 
> > The parameter is parsed during normal Xen boot (not during EFI
> > phase), so it only affects diagnostic logging.
> 
> ... this. For xen.efi you want to add code to the command line parsing
> near the top of efi_start(). What to do for the MB2 boot path perhaps
> the only thing there is to peek into the command line (see
> arch/x86/boot/cmdline.c).

See also my response on v1 - for MB2 path, look at efi_multiboot2().

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

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