Re: [tip: x86/urgent] x86/boot: Pull up cmdline preparation and early param parsing

[Mike Rapoport]

On Thu, Dec 09, 2021 at 04:28:48PM +0100, Borislav Petkov wrote:
> On Thu, Dec 09, 2021 at 04:26:55PM +0100, Juergen Gross wrote:
> > Sigh. This will break Xen PV. Again. The comment above the call of
> > early_reserve_memory() tells you why.
> 
> I know. I was just looking at how to fix that particular thing and was
> going to find you on IRC to talk to you about it...

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

I.e. revert c0f2077baa41 ("x86/boot: Mark prepare_command_line() __init")
and 8d48bf8206f7 ("x86/boot: Pull up cmdline preparation and early param
parsing") and add the patch below on top.

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 49b596db5631..da36b8f8430b 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -713,9 +713,6 @@ static void __init early_reserve_memory(void)
 
 	early_reserve_initrd();
 
-	if (efi_enabled(EFI_BOOT))
-		efi_memblock_x86_reserve_range();
-
 	memblock_x86_reserve_range_setup_data();
 
 	reserve_ibft_region();
@@ -890,6 +887,9 @@ void __init setup_arch(char **cmdline_p)
 
 	parse_early_param();
 
+	if (efi_enabled(EFI_BOOT)) {
+		efi_memblock_x86_reserve_range();
+
 #ifdef CONFIG_MEMORY_HOTPLUG
 	/*
 	 * Memory used by the kernel cannot be hot-removed because Linux

-- 
Sincerely yours,
Mike.