This should be finally fixed by (in combination with QEMU 2.9.0):

commit 2a586b4402a7637e0bef9a2876d065c0ce6bfef1
Refs: v3.1.0-9-g2a586b440
Author:     Jiri Denemark <email address hidden>
AuthorDate: Mon Jan 30 16:10:22 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:56 2017 +0100

    qemucapstest: Update test data for QEMU 2.9.0

    Signed-off-by: Jiri Denemark <email address hidden>

commit 0bde051f3de02b1be25ea4a4d9f062abfa3d1397
Refs: v3.1.0-10-g0bde051f3
Author:     Jiri Denemark <email address hidden>
AuthorDate: Mon Jan 30 16:10:49 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:56 2017 +0100

    domaincapstest: Add test data for QEMU 2.9.0

    Signed-off-by: Jiri Denemark <email address hidden>

commit d2f8f3052d48f284d56e27c98ce7a2ce6c656e59
Refs: v3.1.0-11-gd2f8f3052
Author:     Jiri Denemark <email address hidden>
AuthorDate: Wed Feb 15 10:18:53 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:56 2017 +0100

    docs: Update description of the host-model CPU mode

    Signed-off-by: Jiri Denemark <email address hidden>

commit 4c0723a1d75b981e8939c4c5b6bde7607fc7301e
Refs: v3.1.0-12-g4c0723a1d
Author:     Jiri Denemark <email address hidden>
AuthorDate: Mon Jan 30 16:30:13 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:56 2017 +0100

    qemu: Rename hostCPU/feature element in capabilities cache

    The element will be generalized in the following commits.

    Signed-off-by: Jiri Denemark <email address hidden>

commit 03a34f6b84da009291e8651aba71df8a6761d081
Refs: v3.1.0-13-g03a34f6b8
Author:     Jiri Denemark <email address hidden>
AuthorDate: Wed Feb 22 15:46:47 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:56 2017 +0100

    qemu: Prepare for more types in qemuMonitorCPUModelInfo

    Signed-off-by: Jiri Denemark <email address hidden>

commit 2fc215dd2ad4b88c1054da804c4c45b3d4e5c2fa
Refs: v3.1.0-14-g2fc215dd2
Author:     Jiri Denemark <email address hidden>
AuthorDate: Wed Feb 22 16:01:30 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:56 2017 +0100

    qemu: Store more types in qemuMonitorCPUModelInfo

    While query-cpu-model-expansion returns only boolean features on s390,
    but x86_64 reports some integer and string properties which we are
    interested in.

    Signed-off-by: Jiri Denemark <email address hidden>

commit d7f054a512a911a386d9bbeec51379e4bb843ca5
Refs: v3.1.0-15-gd7f054a51
Author:     Jiri Denemark <email address hidden>
AuthorDate: Wed Feb 22 16:51:50 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:57 2017 +0100

    qemu: Probe "max" CPU model in TCG

    Querying "host" CPU model expansion only makes sense for KVM. QEMU 2.9.0
    introduces a new "max" CPU model which can be used to ask QEMU what the
    best CPU it can provide to a TCG domain is.

    Signed-off-by: Jiri Denemark <email address hidden>

commit f0138289920d5204c1654bc9b17115d1a315d62e
Refs: v3.1.0-16-gf01382899
Author:     Jiri Denemark <email address hidden>
AuthorDate: Wed Jan 11 14:36:34 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:57 2017 +0100

    qemu: Get host CPU model from QEMU on x86_64

    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=1335534

    Signed-off-by: Jiri Denemark <email address hidden>

commit be3d59754b1a1da174ff1796882a0ceb35e198e8
Refs: v3.1.0-17-gbe3d59754
Author:     Jiri Denemark <email address hidden>
AuthorDate: Tue Jan 31 13:44:00 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:57 2017 +0100

    qemu: Use enum for CPU model expansion type

    Signed-off-by: Jiri Denemark <email address hidden>

commit bb3363c90b5b19c37f8e5b8f512eb00014d2dae4
Refs: v3.1.0-18-gbb3363c90
Author:     Jiri Denemark <email address hidden>
AuthorDate: Thu Feb 23 13:53:51 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:57 2017 +0100

    qemu: Use full CPU model expansion on x86

    The static CPU model expansion is designed to return only canonical
    names of all CPU properties. To maintain backwards compatibility libvirt
    is stuck with different spelling of some of the features, but we need to
    use the full expansion to get the additional spellings. In addition to
    returning all spelling variants for all properties the full expansion
    will contain properties which are not guaranteed to be migration
    compatible. Thus, we need to combine both expansions. First we need to
    call the static expansion to limit the result to migratable properties.
    Then we can use the result of the static expansion as an input to the
    full expansion to get both canonical names and their aliases.

    Signed-off-by: Jiri Denemark <email address hidden>

commit 2f882dbfa92c14d585a786a42d284b63ffdca4e3
Refs: v3.1.0-19-g2f882dbfa
Author:     Jiri Denemark <email address hidden>
AuthorDate: Thu Feb 23 14:31:23 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:57 2017 +0100

    qemu: Make virQEMUCapsInitCPUModel testable

    Signed-off-by: Jiri Denemark <email address hidden>

commit d065934cd07c01fbb29f25bbb223eb4ce126a90e
Refs: v3.1.0-20-gd065934cd
Author:     Jiri Denemark <email address hidden>
AuthorDate: Wed Feb 1 17:48:41 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:57 2017 +0100

    cputest: Switch host CPU data scripts to model expansion

    Instantiating "host" CPU and querying it using qom-get has been the only
    way of probing host CPU via QEMU until 2.9.0 implemented
    query-cpu-model-expansion for x86_64. Even though libvirt never really
    used the old way its result can be easily converted into the one
    produced by query-cpu-model-expansion. Thus we can reuse the original
    test data and possible get new data from hosts where QEMU does not
    support the new QMP command.

    Signed-off-by: Jiri Denemark <email address hidden>

commit d46a1aa4d8caafe977cc41a80ef86af1d10e60b7
Refs: v3.1.0-21-gd46a1aa4d
Author:     Jiri Denemark <email address hidden>
AuthorDate: Mon Feb 13 14:59:42 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:57 2017 +0100

    cputest: Convert all json data files to query-cpu-model-expansion

    Converted by running the following command, renaming the files as
    *.new, and committing only the *.new files.

        (cd tests/cputestdata; ./cpu-convert.py *.json)

    Signed-off-by: Jiri Denemark <email address hidden>

commit a19696b5924e7512dcca4f30d15147036708389e
Refs: v3.1.0-22-ga19696b59
Author:     Jiri Denemark <email address hidden>
AuthorDate: Mon Feb 13 10:33:52 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:57 2017 +0100

    cputest: Test virQEMUCapsInitCPUModel

    The original test didn't use family/model numbers to make better
    decisions about the CPU model and thus mis-detected the model in the two
    cases which are modified in this commit. The detected CPU models now
    match those obtained from raw CPUID data.

    Signed-off-by: Jiri Denemark <email address hidden>

commit 5e4fc2ef993343643587f2b079b63f2c9f038e6f
Refs: v3.1.0-23-g5e4fc2ef9
Author:     Jiri Denemark <email address hidden>
AuthorDate: Mon Feb 13 15:04:38 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:57 2017 +0100

    cputest: Drop obsolete CPU test data files

    Signed-off-by: Jiri Denemark <email address hidden>

commit 8907204cd83f0ca29c48d19bbf2778132d8578a2
Refs: v3.1.0-24-g8907204cd
Author:     Jiri Denemark <email address hidden>
AuthorDate: Mon Feb 13 15:06:35 2017 +0100
Commit:     Jiri Denemark <email address hidden>
CommitDate: Fri Mar 3 19:57:57 2017 +0100

    cputest: Drop .new suffix from CPU test data files

    Signed-off-by: Jiri Denemark <email address hidden>