Update s390x capabilities for QEMU 4.2 with the actual GA version for
QEMU and on the latest z15 machine.
This picks up the new blockdev capability, so we need to refresh a bunch
of test cases as well.
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>
On s390 machines host-passthrough and host-model CPUs result in the same
guest ABI (with QEMU new enough to be able to tell us what "host" CPU is
expanded to, which was implemented around 2.9.0). So instead of using
host-passthrough CPU when there's no CPU specified in a domain XML we
can safely use host-model and benefit from CPU compatibility checks
during migration, snapshot restore and similar operations.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
When starting a domain without a CPU model specified in the domain XML,
QEMU will choose a default one. Which is fine unless the domain gets
migrated to another host because libvirt doesn't perform any CPU ABI
checks and the virtual CPU provided by QEMU on the destination host can
differ from the one on the source host.
With QEMU 4.2.0 we can probe for the default CPU model used by QEMU for
a particular machine type and store it in the domain XML. This way the
chosen CPU model is more visible to users and libvirt will make sure
the guest will see the exact same CPU after migration.
Architecture specific notes
- aarch64: We only set the default CPU for TCG domains as KVM requires
explicit "-cpu host" to work.
- ppc64: The default CPU for KVM is "host" thanks to some hacks in QEMU,
we will translate the default model to the model corresponding to the
host CPU ("POWER8" on a Power8 host, "POWER9" on Power9 host, etc.).
This is not a problem as the corresponding CPU model is in fact an
alias for "host". This is probably not ideal, but it's not wrong and
the default virtual CPU configured by libvirt is the same QEMU would
use. TCG uses various CPU models depending on machine type and its
version.
- s390x: The default CPU for KVM is "host" while TCG defaults to "qemu".
- x86_64: The default CPU model (qemu64) is not runnable on any host
with KVM, but QEMU just disables unavailable features and starts
happily.
https://bugzilla.redhat.com/show_bug.cgi?id=1598151https://bugzilla.redhat.com/show_bug.cgi?id=1598162
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
