WinPE blue screen in guest w/HyperV enlightenment

WinPE blue screen in guest w/HyperV enlightenment

[Brian Rak]

I've been trying to get WinPE to boot correctly as a KVM guest. I've 
found that WinPE > 4.0 (aka server 2012) will boot fine in KVM, but 
older versions will not.  I only see this issue if the HyperV 
enlightenments are enabled.

A screenshot of the crash can be found at: 
https://dl.dropboxusercontent.com/u/2078961/winpe_kvm.png

Host:
CentOS 6 x64
3.10.9-1.el6.x86_64
qemu 1.6.0
/usr/libexec/qemu-kvm -name SRVID4538 -S -machine 
pc-i440fx-1.6,accel=kvm,usb=off -cpu 
host,hv_relaxed,hv_vapic,hv_spinlocks=0x1000 -m 8192 -smp 
4,sockets=2,cores=16,threads=2 -uuid 
4807c195-f10c-404d-b2da-de1b726c19e5 -no-user-config -nodefaults 
-chardev 
socket,id=charmonitor,path=//var/lib/libvirt/qemu/SRVID4538.monitor,server,nowait 
-mon chardev=charmonitor,id=monitor,mode=readline -rtc 
base=utc,driftfix=slew -no-hpet -boot c -usb -drive 
file=/dev/vmimages/SRVID4538,if=none,id=drive-virtio-disk0,format=raw,cache=none,aio=native 
-device 
virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0 
-drive if=none,media=cdrom,id=drive-ide0-1-0,readonly=on,format=raw 
-device ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -vnc 
127.0.0.1:4538,password -k en-us -vga cirrus -device 
pci-assign,host=06:10.0,id=hostdev0,bus=pci.0,addr=0x3,rombar=1,romfile=/usr/share/gpxe/80861520.rom 
-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5

If I change '-cpu host,hv_relaxed,hv_vapic,hv_spinlocks=0x1000' to '-cpu 
host', WinPE boots up fine.

Is this a bug in KVM?  I'm not really sure what other information would 
be helpful here.