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x86: Make E820_X_MAX unconditionally larger than E820MAX 

It's really not necessary to limit E820_X_MAX to 128 in the non-EFI
case.  This commit drops E820_X_MAX's dependency on CONFIG_EFI, so that
E820_X_MAX is always at least slightly larger than E820MAX.

The real motivation behind this is actually to prevent some issues in
the Xen kernel, where the XENMEM_machine_memory_map hypercall can
produce an e820 map larger than 128 entries, even on systems where the
original e820 table was quite a bit smaller than that, depending on how
many IOAPICs are installed on the system.

Signed-off-by: Alex Thorlton <athorlton@sgi.com>
Suggested-by: Ingo Molnar <mingo@redhat.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
This commit is contained in:
Alex Thorlton 2016-12-05 11:49:13 -06:00 committed by Juergen Gross
parent 577f79e411
commit 9d2f86c6ca
1 changed files with 8 additions and 4 deletions
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12
arch/x86/include/asm/e820.h
View File

@ -1,13 +1,17 @@
#ifndef _ASM_X86_E820_H
#define _ASM_X86_E820_H
#ifdef CONFIG_EFI
/*
* E820_X_MAX is the maximum size of the extended E820 table. The extended
* table may contain up to 3 extra E820 entries per possible NUMA node, so we
* make room for 3 * MAX_NUMNODES possible entries, beyond the standard 128.
* Also note that E820_X_MAX *must* be defined before we include uapi/asm/e820.h.
*/
#include <linux/numa.h>
#define E820_X_MAX (E820MAX + 3 * MAX_NUMNODES)
#else /* ! CONFIG_EFI */
#define E820_X_MAX E820MAX
#endif
#include <uapi/asm/e820.h>
#ifndef __ASSEMBLY__
/* see comment in arch/x86/kernel/e820.c */
extern struct e820map *e820;