Re: [PATCH] x86/efi: defer freeing of boot services memory

[Mike Rapoport <rppt@kernel.org>]

On Tue, Feb 24, 2026 at 11:53:50AM +0200, Mike Rapoport wrote:
> On Tue, Feb 24, 2026 at 10:29:59AM +0100, Ard Biesheuvel wrote:
> > 
> > 
> > On Tue, 24 Feb 2026, at 10:28, Mike Rapoport wrote:
> > > On Mon, Feb 23, 2026 at 01:18:41PM +0100, Ard Biesheuvel wrote:
> > >> On Mon, 23 Feb 2026, at 12:40, Mike Rapoport wrote:
> > >> > On Mon, Feb 23, 2026 at 12:17:22PM +0100, Ard Biesheuvel wrote:
> > >> >>
> > >> >> > I wasn't sure it's Ok to only unmap them, but leave in efi.memmap, that's
> > >> >> > why I didn't use the existing EFI memory map.
> > >> >> >
> > >> >> > Now thinking about it, if the unmapping can happen later, maybe we'll just
> > >> >> > move the entire efi_free_boot_services() to an initcall?
> > >> >> 
> > >> >> As long as it is pre-SMP, as that code also contains a quirk to allocate
> > >> >> the real mode trampoline if all memory below 1 MB is used for boot
> > >> >> services.
> > >> >
> > >> > initcall is long after SMP. It the real mode trampoline allocation is the
> > >> > only thing that should happen pre-SMP?
> > >> 
> > >> early_initcall() should be early enough, those run before SMP init.
> > >
> > > I don't think so. All initcalls run quite late in boot, early ones just run
> > > before the others.
> > > 
> > 
> > It is documented as running before SMP. If that is no longer true, we should fix the documentation.
> 
> Ah, my bad, it is running before SMP. 

But then it also runs before page_alloc_init_late(), and it's too early for
free reserved memory with CONFIG_DEFERRED_STRUCT_INIT=y :(

-- 
Sincerely yours,
Mike.