Commit 5dc64a34 authored Oct 10, 2008 by Ian Campbell Committed by Ingo Molnar Oct 10, 2008

xen: do not reserve 2 pages of padding between hypervisor and fixmap.



When reserving space for the hypervisor the Xen paravirt backend adds
an extra two pages (this was carried forward from the 2.6.18-xen tree
which had them "for safety"). Depending on various CONFIG options this
can cause the boot time fixmaps to span multiple PMDs which is not
supported and triggers a WARN in early_ioremap_init().

This was exposed by 2216d199 which
moved the dmi table parsing earlier.
    x86: fix CONFIG_X86_RESERVE_LOW_64K=y

    The bad_bios_dmi_table() quirk never triggered because we do DMI setup
    too late. Move it a bit earlier.

There is no real reason to reserve these two extra pages and the
fixmap already incorporates FIX_HOLE which serves the same
purpose. None of the other callers of reserve_top_address do this.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent eefb47f6

arch/x86/xen/enlighten.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1370,7 +1370,7 @@ static void __init xen_reserve_top(void)
		if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
		top = pp.virt_start;

		reserve_top_address(-top + 2 * PAGE_SIZE);
		reserve_top_address(-top);
		#endif /* CONFIG_X86_32 */
		}