[Qemu-discuss] Black screens when connecting to Windows 10 vm's

[Sebastian Arcus]

I've had this problem for almost a year now on one of my vm servers 
running qemu/kvm with libvirt on Linux, With Windows 10 vms. Almost 
every day, when users come to login remotely through RDP, they only get 
a black screen and nothing else. I have to reboot the vm, and then 
everything is fine.

1. CTRL+ALT+END in the rdp window doesn't bring up the Task Manager.
2. I can still ping the vm.
3. I can shut it down with virsh shutdown <vm_name>

I have tried upgrading qemu and libvirt - I am now on qemu 2.10.2 and 
libvirt 4.0.0. I have another vm server with virtually the same config, 
and never have this problem.

I've also tried changing the video from virtio to vga, and that didn't 
make any difference.

The server runs 2 Windows 10 vm's, has 12GB of ram and an Intel Core 
i5-4460 cpu.

I can't figure out how to narrow things down further - or even to figure 
out if it is somehow caused by Windows, or by qemu/kvm. Any suggestions 
are welcome.

Below is my graphics config from libvirt (I've enabled VNC temporarily 
to be able to get back in when RDP stops working):


<graphics type='vnc' port='5900' autoport='no' listen='0.0.0.0' 
keymap='en-gb'>
   <listen type='address' address='0.0.0.0'/>
</graphics>
<video>
   <model type='vga' vram='32768' heads='1' primary='yes'/>
   <address type='pci' domain='0x0000' bus='0x00' slot='0x02' 
function='0x0'/>
</video>