Re: [tip:x86/mm] x86: make e820_update_range() handle small rangeupdate

From: Ingo Molnar
Date: Sat Mar 14 2009 - 14:40:57 EST



* Yinghai Lu <yinghai@xxxxxxxxxx> wrote:

> Ingo Molnar wrote:
> > * Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> >
> >> Commit-ID: 78a8b35bc7abf8b8333d6f625e08c0f7cc1c3742
> >> Gitweb: http://git.kernel.org/tip/78a8b35bc7abf8b8333d6f625e08c0f7cc1c3742
> >> Author: Yinghai Lu <yinghai@xxxxxxxxxx>
> >> AuthorDate: Thu, 12 Mar 2009 22:36:01 -0700
> >> Commit: Ingo Molnar <mingo@xxxxxxx>
> >> CommitDate: Sat, 14 Mar 2009 12:20:07 +0100
> >>
> >> x86: make e820_update_range() handle small range update
> >>
> >> Impact: enhance e820 code to handle more cases
> >>
> >> Try to handle new range which could be covered by one entry.
> >>
> >> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> >> Cc: jbeulich@xxxxxxxxxx
> >> LKML-Reference: <49B9F0C1.10402@xxxxxxxxxx>
> >> Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
> >
> > -tip testing found a bootup crash + reboot due to this patch.
> >
> > config attached. The bootup crashes here:
> >
> > [ 0.000000] MTRR variable ranges enabled:
> > [ 0.000000] 0 base 0000000000 mask FFC0000000 write-back
> > [ 0.000000] 1 disabled
> > [ 0.000000] 2 disabled
> > [ 0.000000] 3 disabled
> > [ 0.000000] 4 disabled
> > [ 0.000000] 5 disabled
> > [ 0.000000] 6 disabled
> > [ 0.000000] 7 disabled
> > [ 0.000000] x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106
> > [ 0.000000] get_mtrr: cpu0 reg00 base=0000000000 size=0000040000 write-back
> > [ reboot ]
> >
>
> what does the e820 map look like?

[ 0.000000] BIOS-provided physical RAM map:
[ 0.000000] BIOS-e820: 0000000000000000 - 000000000009f800 (usable)
[ 0.000000] BIOS-e820: 000000000009f800 - 00000000000a0000 (reserved)
[ 0.000000] BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
[ 0.000000] BIOS-e820: 0000000000100000 - 000000003fff0000 (usable)
[ 0.000000] BIOS-e820: 000000003fff0000 - 000000003fff3000 (ACPI NVS)
[ 0.000000] BIOS-e820: 000000003fff3000 - 0000000040000000 (ACPI data)
[ 0.000000] BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
[ 0.000000] BIOS-e820: 00000000fec00000 - 0000000100000000 (reserved)

Ingo
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