Commit 9d2f86c6 authored Dec 05, 2016 by Alex Thorlton Committed by Juergen Gross Dec 09, 2016

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>

parent 577f79e4

arch/x86/include/asm/e820.h

+8 −4

Original line number	Diff line number	Diff line
		#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;