Description of problem:
boot guest -cpu host on Westmere host and run sandra, guest BSOD, send system_reset cmd after dump info is 100% collected, guest hang.

Version-Release number of selected component (if applicable):
qemu-kvm-0.12.1.2-2.152.el6.x86_64

How reproducible:
sometime

Steps to Reproduce:
1. cmd:
/usr/libexec/qemu-kvm -monitor stdio -drive file=/mnt/images/win2008r2-64-virtio.qcow2,index=0,if=none,id=drive-virtio-disk1,media=disk,cache=none,format=qcow2,aio=native -device virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk1,id=virtio-disk1 -device virtio-net-pci,netdev=idOpKnu6,mac=9a:c7:11:c1:0e:1a,netdev=idOpKnu6,id=ndev00idOpKnu6,bus=pci.0,addr=0x3 -netdev tap,id=idOpKnu6,vhost=on,script='/usr/local/staf/test/RHEV/kvm-new/autotest/client/tests/kvm/scripts/qemu-ifup-switch',downscript='no' -m 10240 -smp 16,cores=2,threads=4,sockets=2 -cpu host -spice port=8000,disable-ticketing -vga qxl -rtc base=localtime,clock=host,driftfix=none  -boot order=cdn,once=c,menu=off   -usbdevice tablet -enable-kvm


2. run sandra on guest, guest BSOD (bug 691382)
3. send system_reset to reboot guest after dump info is 100% collected
  
Actual results:
guest hang

Expected results:


Additional info:

1. top
Tasks:  18 total,   2 running,  16 sleeping,   0 stopped,   0 zombie
Cpu(s):  7.3%us,  4.1%sy,  0.0%ni, 88.7%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:  12184372k total, 11055460k used,  1128912k free,    47504k buffers
Swap: 14417912k total,        0k used, 14417912k free,   252532k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  WCHAN     COMMAND
29559 root      20   0 11.7g 9.8g 3420 S  0.0 84.6   5:18.81 kvm_vcpu_ qemu-kvm
29560 root      20   0 11.7g 9.8g 3420 S  0.0 84.6   5:16.29 kvm_vcpu_ qemu-kvm
29561 root      20   0 11.7g 9.8g 3420 S  0.0 84.6   5:16.64 kvm_vcpu_ qemu-kvm
29562 root      20   0 11.7g 9.8g 3420 S  0.0 84.6   5:17.23 kvm_vcpu_ qemu-kvm
29563 root      20   0 11.7g 9.8g 3420 S  0.0 84.6   5:15.26 kvm_vcpu_ qemu-kvm
29564 root      20   0 11.7g 9.8g 3420 S  0.0 84.6   5:15.99 kvm_vcpu_ qemu-kvm
29565 root      20   0 11.7g 9.8g 3420 S  0.0 84.6   5:15.62 kvm_vcpu_ qemu-kvm
29566 root      20   0 11.7g 9.8g 3420 S  0.0 84.6   0:16.44 kvm_vcpu_ qemu-kvm
29567 root      20   0 11.7g 9.8g 3420 S  0.0 84.6   0:12.23 kvm_vcpu_ qemu-kvm
29568 root      20   0 11.7g 9.8g 3420 S  0.0 84.6   0:11.18 kvm_vcpu_ qemu-kvm
29569 root      20   0 11.7g 9.8g 3420 S  0.0 84.6   0:10.72 kvm_vcpu_ qemu-kvm
29571 root      20   0 11.7g 9.8g 3420 S  0.0 84.6   0:11.06 kvm_vcpu_ qemu-kvm
29572 root      20   0 11.7g 9.8g 3420 S  0.0 84.6   0:10.35 kvm_vcpu_ qemu-kvm
29573 root      20   0 11.7g 9.8g 3420 S  0.0 84.6   0:09.51 kvm_vcpu_ qemu-kvm
29574 root      20   0 11.7g 9.8g 3420 S  0.0 84.6   0:00.94 epoll_wai qemu-kvm
29546 root      20   0 11.7g 9.8g 3420 S  0.3 84.6   0:29.01 poll_sche qemu-kvm
29558 root      20   0 11.7g 9.8g 3420 R 99.8 84.6   8:42.36 -         qemu-kvm

2. kvm_stat
kvm statistics

 efer_reload                  0       0
 exits                622365869 1964802
 fpu_reload              713751       0
 halt_exits              635853       0
 halt_wakeup             629704       0
 host_state_reload     20992636       2
 hypercalls                   0       0
 insn_emulation         1956234       0
 insn_emulation_fail          0       0
 invlpg                       0       0
 io_exits              20193233       0
 irq_exits              3002568     549
 irq_injections          752140       0
 irq_window               19863       0
 largepages                   2       0
 mmio_exits              124602       0
 mmu_cache_miss             351       0

3. host (12Gmem & 16 cpu)
kernel:
2.6.32-125.el6.x86_64

cpuinfo:
processor	: 15
vendor_id	: GenuineIntel
cpu family	: 6
model		: 44
model name	: Intel(R) Xeon(R) CPU           E5620  @ 2.40GHz
stepping	: 2
cpu MHz		: 2394.219
cache size	: 12288 KB
physical id	: 0
siblings	: 8
core id		: 10
cpu cores	: 4
apicid		: 21
initial apicid	: 21
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt aes lahf_lm ida arat tpr_shadow vnmi flexpriority ept vpid
bogomips	: 4787.83
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual

4. guest
win2008r2