Here's a weird one I just noticed: I've been using a Windows 10 virtual machine to run my tax software. I've got it displayed in virt-viewer and all is well, then I close the virt-viewer window and leave the KVM running. About 5 minutes later I see a cpu suddenly pegged at 100%. I run top and see that qemu is the culprit. I start virt-viewer again, and it goes back to normal.
Anyone else seen this? Why would nobody looking at it make it go crazy I wonder?