If one has e.g.
<guest>
<os_type>hvm</os_type>
<arch name='x86_64'>
<wordsize>64</wordsize>
<emulator>/usr/bin/qemu-system-x86_64</emulator>
<machine>pc-0.11</machine>
<machine canonical='pc-0.11'>pc</machine>
<machine>pc-0.10</machine>
<machine>isapc</machine>
<domain type='qemu'>
</domain>
<domain type='kvm'>
<emulator>/usr/bin/kvm</emulator>
<machine>pc</machine>
<machine>isapc</machine>
</domain>
</arch>
</guest>
and start a guest with:
<domain type='kvm'>
...
<os>
<type arch='x86_64'>hvm</type>
...
</os>
</domain>
then the default machine type should be 'pc' and not 'pc-0.11'
Issue was reported by Anton Protopopov.
* src/capabilities.[ch]: pass the domain type to
virCapabilitiesDefaultGuestArch() and use it to look up the default
machine type from a specific guest domain if needed.
* src/conf/domain_conf.c, src/xen/xm_internal.c: update
* tests/qemuxml2argvdata/qemuxml2argv-machine-aliases2.xml: update
the domain type to 'kvm' and remove the machine type to check
that the default gets looked up correctly
* tests/testutilsqemu.c: add a machine types list for /usr/bin/kvm
which doesn't have any aliases, while the guest has aliases
* tests/qemuxml2argvdata/qemuxml2argv-machine-aliases2.*,
tests/qemuxml2argvtest.c: add a test using /usr/bin/kvm and make
sure that 'pc' machine type doesn't get canonicalized using the
aliases in the guest machine type list
