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x86/setup: Merge several reservations of start of memory

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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: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210302100406.22059-3-rppt@kernel.org
This commit is contained in:
Mike Rapoport 2021-03-02 12:04:06 +02:00 committed by Borislav Petkov
parent a799c2bd29
commit 4c674481dc
1 changed files with 10 additions and 9 deletions
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19
arch/x86/kernel/setup.c
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@ -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();
}
/*