[libvirt PATCH 00/16] expose tainting and deprecations in public API

Daniel P. Berrangé berrange at redhat.com
Fri Jan 22 17:18:20 UTC 2021


Libvirt has a notion of "tainting" which we use to mark a guest which
has some undesirable configuration or behaviour from libvirt's POV.
This ends up in the libvirtd logs and in the per-VM log file, but is
not exposed to management applications directly.

QMP has the ability to report whether a CPU or machine type is
deprecated.

QEMU itself prints warnings to stderr which end up in the per VM log:

2021-01-22T12:22:53.566239Z qemu-system-x86_64: Machine type 'pc-1.3' is depr=
ecated: use a newer machine type instead
2021-01-22T12:22:53.566613Z qemu-system-x86_64: warning: CPU model Icelake-Cl=
ient-x86_64-cpu is deprecated -- use Icelake-Server instead

We can use the deprecation info from QMP to add tainting to the
domain too. This will appear in the pre-VM log file again:

2021-01-22 12:22:53.492+0000: Domain id=3D2 is tainted: deprecated-configurat=
ion (machine type 'pc-1.3')
2021-01-22 12:22:53.492+0000: Domain id=3D2 is tainted: deprecated-configurat=
ion (CPU model 'Icelake-Client')

and more usefully in the libvirtd log

2021-01-22 13:18:09.619+0000: 3299849: warning :
qemuDomainObjTaintMsg:6208 :
Domain id=3D3 name=3D'demo' uuid=3Deadf8ef0-bf14-4c5f-9708-4a19bacf9e81
is tainted: deprecated-configuration (machine type 'pc-1.3')

2021-01-22 13:18:09.619+0000: 3299849: warning :
qemuDomainObjTaintMsg:6208 :
Domain id=3D3 name=3D'demo' uuid=3Deadf8ef0-bf14-4c5f-9708-4a19bacf9e81
is tainted: deprecated-configuration (CPU model 'Icelake-Client')

This series goes further and also exposes the deprecation info in the
capabilities (machine types) or domain capabilities (CPU) XML. This
lets mgmt apps avoid using the feature upfront if desired.

Finally both deprecation messages and tainting flags are exposed in
new public APIs, and wired into virsh

$ virsh dominfo demo
Id:             3
Name:           demo
UUID:           eadf8ef0-bf14-4c5f-9708-4a19bacf9e81
OS Type:        hvm
State:          running
CPU(s):         2
CPU time:       1.3s
Max memory:     1536000 KiB
Used memory:    1536000 KiB
Persistent:     yes
Autostart:      disable
Managed save:   no
Security model: selinux
Security DOI:   0
Security label: unconfined_u:unconfined_r:svirt_t:s0:c578,c807 (permissive)
Tainting:       custom-monitor
                deprecated-config
Deprecations:   CPU model 'Icelake-Client'
                machine type 'pc-1.3'

The deprecations API is simple, just returning a list of free form
opaque strings, which are eeffectively warning messages.

I'm not entirely convinced by tainting API though. I didn't especially
want to expose the virDomainTaintFlags  enum in the public API since it
feels like the enum flags are (almost) all QEMU driver specific. I thus
took the approach of having an API return opaque strings which are
declared to be hypervisor specific.

I'm worried though that mgmt apps will none the less simply match on
the strings to detect things, at which point we might as well just use
an enum after all.

So perhaps it should just be turned into

  virDomainGetTainting(virDomainPtr obj,
                       int **codes,
		       unsigned int flags);

  enum virDomainTaintCodes {
     ....
  }

Daniel P. Berrang=C3=A9 (16):
  qemu: report whether a CPU model is deprecated in dom capabilities
  qemu: report whether a machine type is deprecated in capabilities
  conf: introduce new taint flag for deprecated configuration
  qemu: add ability to associate a string message with taint warning
  qemu: taint the VM if it is using a deprecated CPU model
  qemu: taint the VM if it is using a deprecated machine type
  conf: record deprecation messages against the domain
  qemu: record deprecation messages against the domain
  src: define virDomainGetDeprecations API
  remote: add RPC support for the virDomainGetDeprecations API
  qemu: implement virDomainGetDeprecations API
  tools: report deprecations for 'dominfo' command
  src: define virDomainGetTainting API
  remote: add RPC support for the virDomainGetTainting API
  qemu: implement virDomainGetTainting API
  tools: report tainting for 'dominfo' command

 docs/formatdomaincaps.html.in                 |  10 +-
 docs/schemas/capability.rng                   |   8 ++
 docs/schemas/domaincaps.rng                   |   8 ++
 include/libvirt/libvirt-domain.h              |   7 ++
 src/conf/capabilities.c                       |   2 +
 src/conf/capabilities.h                       |   1 +
 src/conf/domain_capabilities.c                |  14 ++-
 src/conf/domain_capabilities.h                |   4 +-
 src/conf/domain_conf.c                        |  29 ++++-
 src/conf/domain_conf.h                        |   5 +
 src/driver-hypervisor.h                       |  11 ++
 src/libvirt-domain.c                          |  95 +++++++++++++++
 src/libvirt_private.syms                      |   1 +
 src/libvirt_public.syms                       |   6 +
 src/qemu/qemu_capabilities.c                  |  60 +++++++++-
 src/qemu/qemu_capabilities.h                  |   6 +
 src/qemu/qemu_capspriv.h                      |   3 +-
 src/qemu/qemu_domain.c                        | 111 ++++++++++++++++--
 src/qemu/qemu_domain.h                        |   7 ++
 src/qemu/qemu_driver.c                        |  66 +++++++++++
 src/qemu/qemu_monitor.c                       |   1 +
 src/qemu/qemu_monitor.h                       |   2 +
 src/qemu/qemu_monitor_json.c                  |   8 ++
 src/qemu/qemu_process.c                       |   5 +
 src/remote/remote_daemon_dispatch.c           |  91 ++++++++++++++
 src/remote/remote_driver.c                    |  88 ++++++++++++++
 src/remote/remote_protocol.x                  |  39 +++++-
 tests/cputest.c                               |   4 +-
 .../domaincapsdata/qemu_5.2.0-q35.x86_64.xml  |   4 +-
 .../domaincapsdata/qemu_5.2.0-tcg.x86_64.xml  |   4 +-
 tests/domaincapsdata/qemu_5.2.0.x86_64.xml    |   4 +-
 .../caps_4.1.0.x86_64.xml                     |  16 +--
 .../qemucapabilitiesdata/caps_4.2.0.ppc64.xml |   4 +-
 .../caps_4.2.0.x86_64.xml                     |  16 +--
 .../caps_5.0.0.x86_64.xml                     |  16 +--
 .../caps_5.1.0.x86_64.xml                     |  16 +--
 .../caps_5.2.0.x86_64.xml                     |  32 ++---
 tests/testutilsqemu.c                         |   8 +-
 tools/virsh-domain-monitor.c                  |  25 ++++
 39 files changed, 745 insertions(+), 92 deletions(-)

--=20
2.29.2





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