I have 2 running virtual machines.
1. Ubuntu Server 16.04 acting as a headless game server
2. Windows 10 Pro used for gaming and other daily activities
I too can start/stop the Win 10 vm for a period of time after a cold boot but if it is logged in for a certain period of time, when I go to shut it down the entire system will freeze. I can reboot the Ubuntu server at will. It too has a SSD being passed thru.
Win 10 VM
csmccarronwx0082c5e4f6-6991-cd5f-8207-49db04386cc9csmccarronwx00 i440fx-2.5 OVMF110100481101004812/machinehvm/usr/share/qemu/ovmf-x64/OVMF_CODE-pure-efi.fd/etc/libvirt/qemu/nvram/82c5e4f6-6991-cd5f-8207-49db04386cc9_VARS-pure-efi.fddestroyrestartrestart/usr/local/sbin/qemu
Ubuntu Server VM
Ubuntu Server232de5eb-2276-0762-2e29-29dc917ef34dUbuntu Server Q35 OVMF11010048110100484/machinehvm/usr/share/qemu/ovmf-x64/OVMF_CODE-pure-efi.fd/etc/libvirt/qemu/nvram/232de5eb-2276-0762-2e29-29dc917ef34d_VARS-pure-efi.fddestroyrestartrestart/usr/local/sbin/qemu