Commit 4c674481 authored by Mike Rapoport's avatar Mike Rapoport Committed by Borislav Petkov
Browse files

x86/setup: Merge several reservations of start of memory 



Currently, the first several pages are reserved both to avoid leaking
their contents on systems with L1TF and to avoid corrupting BIOS memory.

Merge the two memory reservations.

Signed-off-by: default avatarMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Acked-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210302100406.22059-3-rppt@kernel.org
parent a799c2bd

arch/x86/kernel/setup.c

+10 −9
Original line number Diff line number Diff line
@@ -713,11 +713,6 @@ static int __init parse_reservelow(char *p) 


early_param("reservelow", parse_reservelow);



static void __init trim_low_memory_range(void)

{

	memblock_reserve(0, ALIGN(reserve_low, PAGE_SIZE));

}



static void __init early_reserve_memory(void)

{

	/*
@@ -730,10 +725,17 @@ static void __init early_reserve_memory(void) 
			 (unsigned long)__end_of_kernel_reserve - (unsigned long)_text);



	/*

	 * Make sure page 0 is always reserved because on systems with

	 * L1TF its contents can be leaked to user processes.

	 * The first 4Kb of memory is a BIOS owned area, but generally it is

	 * not listed as such in the E820 table.

	 *

	 * Reserve the first memory page and typically some additional

	 * memory (64KiB by default) since some BIOSes are known to corrupt

	 * low memory. See the Kconfig help text for X86_RESERVE_LOW.

	 *

	 * In addition, make sure page 0 is always reserved because on

	 * systems with L1TF its contents can be leaked to user processes.

	 */

	memblock_reserve(0, PAGE_SIZE);

	memblock_reserve(0, ALIGN(reserve_low, PAGE_SIZE));



	early_reserve_initrd();
@@ -746,7 +748,6 @@ static void __init early_reserve_memory(void) 
	reserve_bios_regions();



	trim_snb_memory();

	trim_low_memory_range();

}



/*