Let me emphasize that I've tested only on Windows 2008. This could work in other versions of Windows (although I really doubt it does).

Hi,

I have made a patch to upstream:
http://lists.nongnu.org/archive/html/qemu-devel/2014-01/msg00227.html

Update to V2:
http://lists.nongnu.org/archive/html/qemu-devel/2014-01/msg01823.html

(In reply to Miki Mishael from comment #2)
> Hi,
> 
> I have made a patch to upstream:
> http://lists.nongnu.org/archive/html/qemu-devel/2014-01/msg00227.html

This bug could be verified pass on qemu-ga-win-7.0.5. 

Steps:
1. Boot up guest with isa serial:

#  /usr/libexec/qemu-kvm -cpu SandyBridge -M pc -enable-kvm -m 2048 -smp 2,sockets=2,cores=1,threads=1 -name rhel6.4-64 -uuid 9a0e67ec-f286-d8e7-0548-0c1c9ec93009 -nodefconfig -nodefaults -monitor stdio -rtc base=utc,clock=host,driftfix=slew -no-kvm-pit-reinjection -no-shutdown -drive file=/root/win7-32-virtio.qcow2,if=none,id=drive-virtio-disk0,format=qcow2,cache=none -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -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 -netdev tap,id=hostnet0,vhost=on -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:d5:51:8a,bus=pci.0,addr=0x3 -chardev socket,id=charserial0,server,nowait,path=/tmp/isa-serial -device isa-serial,chardev=charserial0,id=serial0  -vnc :10 -vga std  -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6 -qmp tcp:0:5555,server,nowait -global PIIX4_PM.disable_s3=0 -global PIIX4_PM.disable_s4=0

2. Install qemu-ga-win msi.

3. Inside guest:
$ qemu-ga.ext -m isa-serial -p COM1

4. On host:
# nc -U /tmp/isa-seiral

5. Send some commands to guest in the terminal of step 4. 

[root@localhost ~]# nc -U /tmp/isa-serial 

{"execute":"guest-ping"}
{"return": {}}

{"execute":"guest-info"}
{"return": {"version": "0.12.1", "supported_commands": [{"enabled": true, "name": "guest-set-vcpus"}, {"enabled": true, "name": "guest-get-vcpus"}, {"enabled": true, "name": "guest-network-get-interfaces"}, {"enabled": true, "name": "guest-suspend-hybrid"}, {"enabled": true, "name": "guest-suspend-ram"}, {"enabled": true, "name": "guest-suspend-disk"}, {"enabled": true, "name": "guest-fstrim"}, {"enabled": true, "name": "guest-fsfreeze-thaw"}, {"enabled": true, "name": "guest-fsfreeze-freeze"}, {"enabled": true, "name": "guest-fsfreeze-status"}, {"enabled": true, "name": "guest-file-flush"}, {"enabled": true, "name": "guest-file-seek"}, {"enabled": true, "name": "guest-file-write"}, {"enabled": true, "name": "guest-file-read"}, {"enabled": true, "name": "guest-file-close"}, {"enabled": true, "name": "guest-file-open"}, {"enabled": true, "name": "guest-shutdown"}, {"enabled": true, "name": "guest-info"}, {"enabled": true, "name": "guest-set-time"}, {"enabled": true, "name": "guest-get-time"}, {"enabled": true, "name": "guest-ping"}, {"enabled": true, "name": "guest-sync"}, {"enabled": true, "name": "guest-sync-delimited"}]}}


{"execute":"guest-sync"}
{"error": {"desc": "Invalid parameter type, expected: integer"}}

  {"execute":"guest-sync", "arguments":{"id":1234}}
{"return": 1234}

{"execute":"guest-sync-delimited", "arguments":{"id":1234}}
�{"return": 1234}
 
{ "execute":"guest-shutdown","arguments":{"mode":"reboot"}} ==> Guest reboots here. 

I also tried to reproduce it with older version qemu-ga-win-7.0.1 and qemu-ga-win-7.0.2, but it fails to install and prompts "RegisterProvider failed. (Error:80042303)(null)". 

As in the latest qemu-ga-win-7.0.5, it could be installed successfully and isa-serial port works well. So I will verified this bug.

This request was resolved in Red Hat Enterprise Linux 7.0.

Contact your manager or support representative in case you have further questions about the request.