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=1598151
https://bugzilla.redhat.com/show_bug.cgi?id=1598162Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

There's no reason for the files to have qemuxml2xmlout- prefix
since they all live under qemuxml2xmloutdata directory.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

The virt type for QEMU can be modified by -machine attribute "accel"
so there is no need to have different QEMU binary paths.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

We use the PreFormat callback for this. Many test cases need to be extended
to pass in proper qemuCaps flags so AssignAddresses doesn't throw errors.

One test case (pcie-root-port-too-many) is dropped, since it was meant
only for checking an error condition in qemuxml2argv, and one we add in
AssignAddresses it errors here too.

Long term I think AssignAddresses should be handled in qemu's PostParse
callback, but that's not entirely straightforward. Handling it here
means we can get the test suite churn over with.

The current code was a little bit odd.  At first we've removed all
possible implicit input devices from domain definition to add them later
back if there was any graphics device defined while parsing XML
description.  That's not all, while formating domain definition to XML
description we at first ignore any input devices with bus different to
USB and VIRTIO and few lines later we add implicit input devices to XML.

This seems to me as a lot of code for nothing.  This patch may look
to be more complicated than original approach, but this is a preferred
way to modify/add driver specific stuff only in those drivers and not
deal with them in common parsing/formating functions.

The update is to add those implicit input devices into config XML to
follow the real HW configuration visible by guest OS.

There was also inconsistence between our behavior and QEMU's in the way,
that in QEMU there is no way how to disable those implicit input devices
for x86 architecture and they are available always, even without graphics
device.  This applies also to XEN hypervisor.  VZ driver already does its
part by putting correct implicit devices into live XML.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

My commit 747761a7 (v1.2.15 only) dropped this bit of logic when filling
in a default arch in the XML:

-    /* First try to find one matching host arch */
-    for (i = 0; i < caps->nguests; i++) {
-        if (caps->guests[i]->ostype == ostype) {
-            for (j = 0; j < caps->guests[i]->arch.ndomains; j++) {
-                if (caps->guests[i]->arch.domains[j]->type == domain &&
-                    caps->guests[i]->arch.id == caps->host.arch)
-                    return caps->guests[i]->arch.id;
-            }
-        }
-    }

That attempt to match host.arch is important, otherwise we end up
defaulting to i686 on x86_64 host for KVM, which is not intended.
Duplicate it in the centralized CapsLookup function.

Additionally add some testcases that would have caught this.

https://bugzilla.redhat.com/show_bug.cgi?id=1219191

The tag is already marked as optional in the schema, so no changes
are needed there.

RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1202606

Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

There were numerous places where numatune configuration (and thus
domain config as well) was changed in different ways.  On some
places this even resulted in persistent domain definition not to be
stable (it would change with daemon's restart).

In order to uniformly change how numatune config is dealt with, all
the internals are now accessible directly only in numatune_conf.c and
outside this file accessors must be used.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>