x86/boot: Move EFI range reservation after cmdline parsing
authorMike Rapoport <rppt@kernel.org>
Mon, 13 Dec 2021 11:27:57 +0000 (12:27 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 29 Dec 2021 11:28:50 +0000 (12:28 +0100)
commit28b03ec2c0c5d541a74180f28d3a10696ccddbb3
tree6506c63357b22730089e5f9e882f042ef5bbcd86
parentf95fcac5d66a0bbb2db4d56b54ef77b27475b7b5
x86/boot: Move EFI range reservation after cmdline parsing

commit 2f5b3514c33fecad4003ce0f22ca9691492d310b upstream.

The memory reservation in arch/x86/platform/efi/efi.c depends on at
least two command line parameters. Put it back later in the boot process
and move efi_memblock_x86_reserve_range() out of early_memory_reserve().

An attempt to fix this was done in

  8d48bf8206f7 ("x86/boot: Pull up cmdline preparation and early param parsing")

but that caused other troubles so it got reverted.

The bug this is addressing is:

Dan reports that Anjaneya Chagam can no longer use the efi=nosoftreserve
kernel command line parameter to suppress "soft reservation" behavior.

This is due to the fact that the following call-chain happens at boot:

  early_reserve_memory
  |-> efi_memblock_x86_reserve_range
      |-> efi_fake_memmap_early

which does

        if (!efi_soft_reserve_enabled())
                return;

and that would have set EFI_MEM_NO_SOFT_RESERVE after having parsed
"nosoftreserve".

However, parse_early_param() gets called *after* it, leading to the boot
cmdline not being taken into account.

See also https://lore.kernel.org/r/e8dd8993c38702ee6dd73b3c11f158617e665607.camel@intel.com

  [ bp: Turn into a proper patch. ]

Signed-off-by: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211213112757.2612-4-bp@alien8.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/x86/kernel/setup.c