ON_QA, since we shipped the RHEL6.5 GA with VSS in RHEL7 Beta
Opened a clone: Bug 1034899 - VSS support for qemu-ga-win - Sync with upstream

Verify this bug with win2012-64 guests with the following version:

Host info:
# uname -r && rpm -q qemu-kvm
3.10.0-64.el7.x86_64
qemu-kvm-1.5.3-30.el7.x86_6
Guest info :
virtio-win-prewhql-0.1-74 (for virtio-serial driver)
qemu-ga-win-6.5-5-x64.msi (guest agent)

Steps:

1. Boot up a guest:

 /usr/libexec/qemu-kvm -cpu SandyBridge -M pc -enable-kvm -m 2G -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 -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x7 -chardev socket,path=/tmp/qga.sock,server,nowait,id=qga0 -device virtserialport,bus=virtio-serial0.0,chardev=qga0,name=org.qemu.guest_agent.0 -drive file=/home/win2012-64-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 -device usb-tablet,id=input0 -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 virtio-serial driver, qemu-ga-win msi, python2.6 64bit inside guest.

3. Send some commands via guest agent. 
(On host)

# nc -U /tmp/qga.sock 

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

4. Run the following script inside guest:
# cat test.py 
import time

result = open("C:\\time.txt", "w")

while 1:
    result.write("%s\n\r" % time.ctime())
    result.flush()
    time.sleep(1)

C:\> test.py (run inside guest)

4. Freeze guest:

(1) Freeze 2~3s (<10s) and then thaw it with guest agent command.

{"execute":"guest-fsfreeze-freeze"}
{"return": 1}
{"execute":"guest-fsfreeze-thaw"}
{"return": 1}

Check "C:\time.txt" file inside guest:

Mon Jan 06 05:01:12 2014
Mon Jan 06 05:01:13 2014
Mon Jan 06 05:01:14 2014
Mon Jan 06 05:01:15 2014
Mon Jan 06 05:01:16 2014
Mon Jan 06 05:01:17 2014
Mon Jan 06 05:01:18 2014
Mon Jan 06 05:01:19 2014 <--- The time is not continuous from here
Mon Jan 06 05:01:24 2014
Mon Jan 06 05:01:25 2014
Mon Jan 06 05:01:26 2014
Mon Jan 06 05:01:27 2014
Mon Jan 06 05:01:28 2014
Mon Jan 06 05:01:29 2014
Mon Jan 06 05:01:30 2014

(2) Freeze for 1 min and then thaw it. (The guest auto-releases the freeze after 10s)

{"execute":"guest-fsfreeze-freeze"}
{"return": 1}
{"execute":"guest-fsfreeze-thaw"}
{"error": {"desc": "couldn't hold writes: fsfreeze is limited up to 10 seconds:  (error: 80042314)"}}
{"execute":"guest-fsfreeze-thaw"}
{"return": 0}

Mon Jan 06 05:01:30 2014
Mon Jan 06 05:01:31 2014
Mon Jan 06 05:01:32 2014
Mon Jan 06 05:01:33 2014
Mon Jan 06 05:01:34 2014
Mon Jan 06 05:01:35 2014
Mon Jan 06 05:01:36 2014
Mon Jan 06 05:01:37 2014 <--- The time is not continuous from here 
Mon Jan 06 05:01:48 2014
Mon Jan 06 05:01:49 2014
Mon Jan 06 05:01:50 2014
Mon Jan 06 05:01:51 2014
Mon Jan 06 05:01:52 2014
Mon Jan 06 05:01:53 2014
Mon Jan 06 05:01:54 2014
Mon Jan 06 05:01:55 2014
Mon Jan 06 05:01:56 2014

Base on above testing, this issue has been fixed correctly, move to VERIFIED status, please correctly me if any mistake.

Best Regards,
sluo

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.