[libvirt] [PATCH 0/2] qemu: Add support for host-model pseries machine option

[Fabiano Rosas]

This series adds support for the -machine,host-model= QEMU option for
for pseries guests.

Pseries guests used to have a node (/proc/device-tree/host-model) in
device-tree that exposed the host's model string so that guest
userspace tools could determine the host machine they were running on.

QEMU used to provide the node by default, but this has been disabled
due to security concerns. There is now a machine option (host-model)
that allows the user to set an arbitrary string to be used as the host
model.

Userspace tools will then be broken unless the user explicitly edits
the domain XML with the desired host model to be exposed to the
guest. However, having an arbitrary string in the domain XML that
needs to be the same for every guest in that machine but different
across host machines would generate issues with XML portability and
more importantly, migration.

So this series implements a generic way for an administrator to enable
the old behavior for a specific guest without allowing arbitrary
strings.

Implementation note:

The 'host-serial' property, which reads /proc/device-tree/system-id in
the host and was also addressed by the QEMU change could be
implemented similarly in the future.

However I see that we're currently populating smbios structures
(virSysinfoDef) with info gathered from /proc/cpuinfo for
architectures that do not use smbios and I think that should be
addressed first.

My idea is to perhaps create new sysinfo types like the existing
'smbios', such as 'cpuinfo' and 'device-tree'.

So to keep the two discussions separated I took advantage of the fact
that the host model happens to also be present at /proc/cpuinfo and
used the smbios structures for now.


Fabiano Rosas (2):
  qemu: Add capability for pseries machine 'host-model' parameter
  qemu: Add support for pseries 'host-model' machine parameter

 docs/formatdomain.html.in                     |  9 ++++++
 docs/schemas/domaincommon.rng                 |  5 ++++
 src/conf/domain_conf.c                        |  4 +++
 src/conf/domain_conf.h                        |  1 +
 src/qemu/qemu_capabilities.c                  |  2 ++
 src/qemu/qemu_capabilities.h                  |  1 +
 src/qemu/qemu_command.c                       | 25 ++++++++++++++--
 src/qemu/qemu_domain.c                        |  1 +
 .../qemucapabilitiesdata/caps_4.0.0.ppc64.xml |  1 +
 tests/qemuxml2argvdata/pseries-features.args  |  3 +-
 tests/qemuxml2argvdata/pseries-features.xml   |  1 +
 tests/qemuxml2argvtest.c                      | 30 ++++++++++++++++++-
 tests/qemuxml2xmloutdata/pseries-features.xml |  1 +
 13 files changed, 79 insertions(+), 5 deletions(-)

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2.20.1