Re: [PATCH v2 2/6] efi: add the LINUX_EFI_POISONED_MEMORY configuration table

[Breno Leitao <leitao@debian.org>]

Hello Pratyush,

On Fri, Aug 21, 2026 at 02:03:30PM +0200, Pratyush Yadav wrote:
> >> +config EFI_POISONED_MEMORY
> >> +	bool "Carry hardware-poisoned pages across kexec"
> >> +	depends on EFI_STUB && MEMORY_FAILURE && 64BIT
> >> +	help
> >> +	  Record page frames that are hardware-poisoned while this kernel runs
> >> +	  into an EFI configuration table, and honor that table early on the
> >> +	  next kernel so a kexec does not hand known-bad RAM back out.
> >> +
> >> +	  If unsure, say N.
> >> +
> >
> > Do we want to make it conditional? Maybe just for everyone with EFI_STUB
> > && MEMORY_FAILURE?
>
> +1. Each config we add is a decision someone has to make when compiling
> the kernel. If they rely on the default, they will miss out on this
> fairly useful feature.
>
> So, is there any downside to just doing this by default without any
> config?

The only downside I see is that this extra config table gets carved
out of main memory for every MEMORY_FAILURE user.

That is roughly 64 KiB per TiB of RAM, though, so maybe it is small
enough to just enable by default?!

Thanks for the review,
--breno