I have a Win10 VM that was working fine prior to the 6.2 upgrade I did around a month ago.  Since the 6.2 upgrade the VM now fails to start around 50% of the time, hanging at the windows loading screen.

 

The VM shows as paused in the VM manager.

 

I have to force kill it and then restart, and it usually works fine the second time.

 

I can see the following in the log:

 

2016-12-11 09:48:33.368+0000: starting up libvirt version: 1.3.1, qemu version: 2.5.1, hostname: Tower
Domain id=1 is tainted: high-privileges
Domain id=1 is tainted: host-cpu
char device redirected to /dev/pts/0 (label charserial0)
KVM internal error. Suberror: 3
extra data[0]: 80000b0e
extra data[1]: 31
RAX=0000000000000001 RBX=ffffe4018abd3750 RCX=ffffe4018abd3750 RDX=fffff80833c827f0
RSI=ffffe4018abafa80 RDI=ffffe4018aba9180 RBP=ffffe4018adcf900 RSP=ffffe4018ac4df20
R8 =ffffe4018abd3750 R9 =ffffe4018abd36c0 R10=0000000000000006 R11=ffffe4018adcfb40
R12=00000004de385657 R13=ffffbe86b5947f70 R14=ffffe4018ab23180 R15=fffff8022c61d000
RIP=fffff80833c82812 RFL=00010202 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =002b 0000000000000000 ffffffff 00c0f300 DPL=3 DS [-WA]
CS =0010 0000000000000000 00000000 00209b00 DPL=0 CS64 [-RA]
SS =0018 0000000000000000 00000000 00409300 DPL=0 DS [-WA]
DS =002b 0000000000000000 ffffffff 00c0f300 DPL=3 DS [-WA]
FS =0053 0000000000000000 0000bc00 0040f300 DPL=3 DS [-WA]
GS =002b ffffe4018aba9000 ffffffff 00c0f300 DPL=3 DS [-WA]
LDT=0000 0000000000000000 ffffffff 00c00000
TR =0040 ffffe4018abafb40 00000067 00008b00 DPL=0 TSS64-busy
GDT= ffffe4018abb6c00 0000006f
IDT= ffffe4018abb6c70 00000fff
CR0=80050031 CR2=ffffe4018abd3754 CR3=00000000001aa000 CR4=001506f8
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 
DR6=00000000ffff0ff0 DR7=0000000000000400
EFER=0000000000000d01
Code=c1 01 83 f8 01 74 1c 8b 41 04 85 c0 74 0d 0f 1f 40 00 f3 90 <8b> 41 04 85 c0 75 f7 33 c0 48 83 c4 20 5b c3 48 8b 41 08 48 8b 51 18 48 8b 49 10 ff 15 7d

 

I don't suppose this means anything to anyone?

I'm getting this problem too. VM's are stable once booted. But every couple of reboots produces a crash before Windows 10 can boot. Usually the first CPU core allocated to the VM is maxed out until I force stop the VM.