The libvirt driver contains some code to calculate the
default machine type given an architecture, by looking it up
in CONF.libvirt.hw_machine_type.
This code will need to be reused when introducing calls to
libvirt's getDomainCapabilities() API, which requires the
machine type as one of the parameters. However those calls
will need to be made from nova.virt.libvirt.host.Host which
has no access to the driver, so move the machine type
calculation code into nova.virt.libvirt.utils so that it can
be reused by both classes.
Also add some unit tests, and warn when an invalid config
value is used.
blueprint: amd-sev-libvirt-support
Change-Id: I055918ff16766c5b106d794a111ad8af8ff9ab23
d2f8995103