Until now host-model CPU mode tried to enable all CPU features supported
by the host CPU even if QEMU/KVM did not support them. This caused a
number of issues and made host-model quite unreliable. Asking QEMU for
the CPU it can provide and the current host makes host-model much more
robust.

This commit fixes the following bugs:

    https://bugzilla.redhat.com/show_bug.cgi?id=1018251
    https://bugzilla.redhat.com/show_bug.cgi?id=1371617
    https://bugzilla.redhat.com/show_bug.cgi?id=1372581
    https://bugzilla.redhat.com/show_bug.cgi?id=1404627
    https://bugzilla.redhat.com/show_bug.cgi?id=870071

In addition to that, the following bug should be mostly limited to cases
when an unsupported feature is explicitly requested:

    https://bugzilla.redhat.com/show_bug.cgi?id=1335534Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

QEMU 2.8.0 adds support for unavailable-features in
query-cpu-definitions reply. The unavailable-features array lists CPU
features which prevent a corresponding CPU model from being usable on
current host. It can only be used when all the unavailable features are
disabled. Empty array means the CPU model can be used without
modifications.

We can use unavailable-features for providing CPU model usability info
in domain capabilities XML:

    <domainCapabilities>
      ...
      <cpu>
        <mode name='host-passthrough' supported='yes'/>
        <mode name='host-model' supported='yes'>
          <model fallback='allow'>Skylake-Client</model>
          ...
        </mode>
        <mode name='custom' supported='yes'>
          <model usable='yes'>qemu64</model>
          <model usable='yes'>qemu32</model>
          <model usable='no'>phenom</model>
          <model usable='yes'>pentium3</model>
          <model usable='yes'>pentium2</model>
          <model usable='yes'>pentium</model>
          <model usable='yes'>n270</model>
          <model usable='yes'>kvm64</model>
          <model usable='yes'>kvm32</model>
          <model usable='yes'>coreduo</model>
          <model usable='yes'>core2duo</model>
          <model usable='no'>athlon</model>
          <model usable='yes'>Westmere</model>
          <model usable='yes'>Skylake-Client</model>
          ...
        </mode>
      </cpu>
      ...
    </domainCapabilities>
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

CPU models (and especially some additional details which we will start
probing for later) differ depending on the accelerator. Thus we need to
call query-cpu-definitions in both KVM and TCG mode to get all data we
want.

Tests in tests/domaincapstest.c are temporarily switched to TCG to avoid
having to squash even more stuff into this single patch. They will all
be switched back later in separate commits.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

The domain capabilities XML is capable of showing whether each guest CPU
mode is supported or not with a possibility to provide additional
details. This patch enhances host-model capability to advertise the
exact CPU model which will be used as a host-model:

    <cpu>
        ...
        <mode name='host-model' supported='yes'>
            <model fallback='allow'>Broadwell</model>
            <vendor>Intel</vendor>
            <feature policy='disable' name='aes'/>
            <feature policy='require' name='vmx'/>
        </mode>
        ...
    </cpu>
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

In case a hypervisor is able to tell us a list of supported CPU models
and whether each CPU models can be used on the current host, we can
propagate this to domain capabilities. This is a better alternative
to calling virConnectCompareCPU for each supported CPU model.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

The patch adds <cpu> element to domain capabilities XML:

    <cpu>
        <mode name='host-passthrough' supported='yes'/>
        <mode name='host-model' supported='yes'/>
        <mode name='custom' supported='yes'>
            <model>Broadwell</model>
            <model>Broadwell-noTSX</model>
            ...
        </mode>
    </cpu>

Applications can use it to inspect what CPU configuration modes are
supported for a specific combination of domain type, emulator binary,
guest architecture and machine type.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

Requires adding the plumbing for <device><video>
The value is <enum name='modelType'> to match the associated domain
XML of <video><model type='XXX'/>

Wire it up for qemu too

Requires adding the plumbing for <device><graphics>
Wire it up for qemu too

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

Enhance the test to cover all capabilities we probe for rather than
testing the flags only.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

Add information about GIC capabilities to virDomainCaps and update
the formatter to include them in the XML output.

Well, even though users can pass the list of UEFI:NVRAM pairs at the
configure time, we may maintain the list of widely available UEFI
ourselves too. And as arm64 begin to rises, OVMF was ported there too.
With a slight name change - it's called AAVMF, with AAVMF_CODE.fd
being the UEFI firmware and AAVMF_VARS.fd being the NVRAM store file.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Check to see if the UEFI binary mentioned in qemu.conf actually
exists, and if so expose it in domcapabilities like

<loader ...>
  <value>/path/to/ovmf</value>
</loader>

We introduce some generic domcaps infrastructure for handling
a dynamic list of string values, it may be of use for future bits.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

As of 54289916 we learned libvirt to use UEFI for domains.
However, management applications may firstly query if libvirt
supports it. And this is where virConnectGetDomainCapabilities()
API comes handy.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

So far only information on disks and host devices are exposed in the
capabilities XML. Well, at least something. Even a new test is
introduced. The qemu capabilities are stolen from already existing
qemucapabilities test. There's one tricky point though. Functions that
checks host's KVM and VFIO capabilities, are impossible to mock
currently. So in the test, we are setting the capabilities by hand.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

This new module holds and formats capabilities for emulator. If you
are about to create a new domain, you may want to know what is the
host or hypervisor capable of. To make sure we don't regress on the
XML, the formatting is not something left for each driver to
implement, rather there's general format function.

The domain capabilities is a lockable object (even though the locking
is not necessary yet) which uses reference counter.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>