Managed to b0rk my Win7 test platform whilst trying to have it recognize a crappy TV tuner card that's Windows only.
Error message received wasn't exactly explicit:
# virsh start Win7
error: Failed to start domain Win7
error: Unable to read from monitor: Connection reset by peer
Er, thanks, I guess.
Bit of sleuthing showed that I needed to check the error log (duh):
# less /var/log/libvirt/qemu/Win7.log
Which showed the error:
2014-06-12 06:06:26.679+0000: starting up
LC_ALL=C PATH=/sbin:/usr/sbin:/bin:/usr/bin QEMU_AUDIO_DRV=none /usr/libexec/qemu-kvm -name Win7 -S -M rhel6.5.0 -enable-kvm -m 2048 -realtime mlock=off -smp 4,sockets=4,cores=1,threads=1 -uuid c8652cca-0437-901c-4b59-b9d3fdc84cd6 -nodefconfig -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/Win7.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime,driftfix=slew -no-shutdown -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive file=/var/lib/libvirt/images/Win7.img,if=none,id=drive-ide0-0-0,format=raw,cache=none -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 -drive file=/media/[snip]/Windows/ISOs/Win7.iso,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 -netdev tap,fd=25,id=hostnet0 -device rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:a9:c1:c7,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -device usb-tablet,id=input0 -vnc 127.0.0.1:0 -vga std -device AC97,id=sound0,bus=pci.0,addr=0x6 -device pci-assign,host=06:00.0,id=hostdev0,configfd=26,bus=pci.0,addr=0x5 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4
char device redirected to /dev/pts/5
Failed to assign device "hostdev0" : Operation not permitted
qemu-kvm: -device pci-assign,host=06:00.0,id=hostdev0,configfd=26,bus=pci.0,addr=0x5: Device 'pci-assign' could not be initialized
2014-06-12 06:06:27.011+0000: shutting down
So, merely had to issue the following command:
virsh edit Win7
Domain Win7 XML configuration edited.
and removed this:
<hostdev mode='subsystem' type='pci' managed='no'>
<source>
<address domain='0x0000' bus='0x06' slot='0x00' function='0x0'/>
</source>
<address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
</hostdev>
Re-start the Virtual Machine:
virsh start Win7
Domain Win7 started
Fixed!