2.6.31-rc7 does not boot on vSMP systems:
[ 8.501108] CPU31: Thermal monitoring enabled (TM1)
[ 8.501127] CPU 31 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 8.650254] CPU31: Intel(R) Xeon(R) CPU E5540 @ 2.53GHz stepping 04
[ 8.710324] Brought up 32 CPUs
[ 8.713916] Total of 32 processors activated (162314.96 BogoMIPS).
[ 8.721489] ERROR: parent span is not a superset of domain->span
[ 8.727686] ERROR: domain->groups does not contain CPU0
[ 8.733091] ERROR: groups don't span domain->span
[ 8.737975] ERROR: domain->cpu_power not set
[ 8.742416]
Ravikiran Thirumalai bisected it to:
| commit 2759c3287d
| x86: don't call read_apic_id if !cpu_has_apic
The problem is that on vSMP systems the CPUID derived
initial-APICIDs are overlapping - so we need to fall
back on hard_smp_processor_id() which reads the local
APIC.
Both come from the hardware (influenced by firmware
though) so it's a tough call which one to trust.
Doing the quirk expresses the vSMP property properly
and also does not affect other systems, so we go for
this solution instead of a revert.
Reported-and-Tested-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Shai Fultheim <shai@scalex86.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <4A944D3C.5030100@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
295594e9cf