Bug 1278808

Description of problem:

Freshly migrated from RDO Icehouse to Kilo, everything is fine except the guest ability to use more than 1 vCPU.

The concerned host are on CentOS 7 3.10.0-229.14.1.el7.x86_64 with :

- libvirt-*1.2.8-16.el7_1.5.x86_64
- qemu-kvm-rhev-1.5.3-86.el7.1.x86_64
- openstack-nova 2015.1.1 from RDO


We just finished three days of debug without results.

The downgrade of packages (i.e. Kernel, libvirt or qemu) doesn't change anything.

The host (i.e compute) is not in power saving mode.

The OpenStack configuration related to NUMA or CPU is by default and use host-model for guests.

The guests are official Ubuntu cloud img/CentOS 7 official cloud img and in-house CentOS 7 cloud img.

The problem doesn't appear with Scientific Linux v6, in fact it uses an older Kernel branch (2.6).

*Guest relevant dmesg :
 
[    0.000000] Linux version 3.10.0-229.7.2.el7.x86_64 (builder.centos.org) (gcc version 4.8.3 20140911 (Red Hat 4.8.3-9) (GCC) ) #1 SMP Tue Jun 23 22:06:11 UTC 2015
[    0.000000] found SMP MP-table at [mem 0x000f2000-0x000f200f] mapped at [ffff8800000f2000]
[    0.000000] Using ACPI (MADT) for SMP configuration information
[    0.000000] smpboot: Allowing 4 CPUs, 0 hotplug CPUs
[    0.007358] Freeing SMP alternatives: 24k freed
[    0.015315] smpboot: CPU0: Intel Xeon E312xx (Sandy Bridge) (fam: 06, model: 2a, stepping: 01)
[    0.023974] smpboot: Booting Node   0, Processors  #1
[   10.034345] smpboot: do_boot_cpu failed(-1) to wakeup CPU#1
[   20.046181] smpboot: do_boot_cpu failed(-1) to wakeup CPU#2
[   30.058121] smpboot: do_boot_cpu failed(-1) to wakeup CPU#3
[   30.059031] smpboot: Total of 1 processors activated (4799.99 BogoMIPS)
[   40.383877] smpboot: Booting Node 0 Processor 1 APIC 0x1
[   50.394081] smpboot: do_boot_cpu failed(-1) to wakeup CPU#1
[   50.480121] smpboot: Booting Node 0 Processor 3 APIC 0x3
[   60.491125] smpboot: do_boot_cpu failed(-1) to wakeup CPU#3
[   60.504397] smpboot: Booting Node 0 Processor 2 APIC 0x2
[   70.515035] smpboot: do_boot_cpu failed(-1) to wakeup CPU#2

Version-Release number of selected component (if applicable):

- Nova host CPU Model: 63 Model name: Intel(R) Xeon(R) CPU E5-2630 v3 @ 2.40GHz
- Guest exposed CPU Model: 42 Model name: Intel Xeon E312xx (Sandy Bridge)
- CentOS 7 3.10.0-229.14.1.el7.x86_64
- libvirt-*1.2.8-16.el7_1.5.x86_64
- qemu-kvm-rhev-1.5.3-86.el7.1.x86_64
- openstack-nova 2015.1.1 from RDO

How reproducible:

Every time.

Steps to Reproduce:
1. Boot a guest with a flavor containing more than 1 vCPU


Additional info:

Qemu CPU instructions for running guests :

-cpu SandyBridge,+invpcid,+erms,+bmi2,+smep,+avx2,+bmi1,+fsgsbase,+abm,+pdpe1gb,+rdrand,+f16c,+osxsave,+movbe,+dca,+pcid,+pdcm,+xtpr,+fma,+tm2,+est,+smx,+vmx,+ds_cpl,+monitor,+dtes64,+pbe,+tm,+ht,+ss,+acpi,+ds,+vme