Cannot start VM on CR node: vring_get_region_caches: Assertion `caches != ((void *)0)' failed.

Symptoms

Cannot start VM on CR node:

# [root@soluscompute ~]# tail -fn0 /var/log/libvirt/qemu/3bd9908d-d226-490b-ba25-672f0bfdf1f9.log
...
2020-03-13 13:54:50.107+0000: Domain id=44 is tainted: host-cpu
2020-03-13T13:54:50.188071Z qemu-kvm: -chardev pty,id=charserial0: char device redirected to /dev/pts/3 (label charserial0)
qemu-kvm: /builddir/build/BUILD/qemu-2.12.0/hw/virtio/virtio.c:212: vring_get_region_caches: Assertion `caches != ((void *)0)' failed.
2020-03-13 13:54:52.717+0000: shutting down, reason=crashed

Cause

CR node is a Hyper-V virtual machine.

The issue is caused by a compatibility issue between Hyper-V nested virtualization and QEMU KVM installed on it.

Resolution

Use physical(bare-metal) server as a SolusIO Compute Resource.