Re: [PATCH 1/2] efi: Call FreePages only if needed

[Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>]

On Wed, Aug 6, 2025 at 7:16 AM Jan Beulich <jbeulich@xxxxxxxx> wrote:
>
> On 05.08.2025 18:32, Ross Lagerwall wrote:
> > If the config file is builtin, cfg.addr will be zero but Xen
> > unconditionally calls FreePages() on the address.
> >
> > Xen may also call FreePages() with a zero address if blexit() is called
> > after this point since cfg.need_to_free is not set to false.
> >
> > The UEFI specification does not say whether calling FreePages() with a
> > zero address is allowed so let's be cautious and use cfg.need_to_free
> > properly.
>
> Well, no, this paragraph makes no sense. Of course this is allowed, but
> not as no-op behavior (like free(NULL) would be), but to free memory
> starting at 0.

Fair enough. This paragraph could simply be dropped then.

>
> > Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
>
> This pretty clearly wants a Fixes: tag, or maybe it even needs to be two.
> I've checked the original code in 4.2, and things were consistent there,
> afaics. So breakage was introduced perhaps in one or two of the many
> re-works.
>

Fixes: 8a71d50ed40b ("efi: Enable booting unified
hypervisor/kernel/initrd images")
Fixes: 04be2c3a0678 ("efi/boot.c: add file.need_to_free")

Do you want an updated patch or can these tweaks be done while committing?

Thanks,
Ross