[libvirt] [RFC PATCH 00/16] Introduce vGPU mdev framework to libvirt

[Michal Privoznik]

On 06.02.2017 13:19, Erik Skultety wrote:
> Finally. It's here. This is the initial suggestion on how libvirt might
> interract with the mdev framework, currently only focussing on the non-managed
> devices, i.e. those pre-created by the user, since that will be revisited once
> we all settled on how the XML should look like, given we might not want to use
> the sysfs path directly as an attribute in the domain XML. My proposal on the
> XML is the following:
> 
> <hostdev mode='subsystem' type='mdev'>  
>     <source>
>         <!-- this is the host's physical device address -->
>         <address domain='0x0000' bus='0x00' slot='0x00' function='0x00'>
>         <uuid>vGPU_UUID<uuid>
>     <source>
>     <!-- target PCI address can be omitted to assign it automatically -->
> </hostdev>
> 
> So the mediated device is identified by the physical parent device visible on
> the host and a UUID which allows us to construct the sysfs path by ourselves,
> which we then put on the QEMU's command line.
> 
> A few remarks if you actually happen to have a machine to test this on:
> - right now the mediated devices are one-time use only, i.e. they have to be
> recreated before every machine boot
> - I wouldn't recommend assigning multiple vGPUs to a single domain
> 
> Once this series is sorted out, we can then continue with 'managed=yes' where
> as Laine pointed out [1], we need to figure out how exactly should the
> management layer hint libvirt which vGPU type should be used for device
> instantiation.
> 
> [1] https://www.redhat.com/archives/libvir-list/2017-January/msg00287.html  
> 
> #pleaseshareyourfeedback
> 
> Thanks,
> Erik
> 
> Erik Skultety (16):
>   util: Introduce new module virmdev
>   conf: Introduce new hostdev device type mdev
>   docs: Update RNG schema to reflect the new hostdev type mdev
>   conf: Adjust the domain parser to work with mdevs
>   Adjust the formatter to reflect the new hostdev type mdev
>   security: dac: Enable labeling of vfio mediated devices
>   security: selinux: Enable labeling of vfio mediated devices
>   conf: Enable cold-plug of a mediated device
>   qemu: Assign PCI addresses for mediated devices as well
>   hostdev: Maintain a driver list of active mediated devices
>   hostdev: Introduce a reattach method for mediated devices
>   qemu: cgroup: Adjust cgroups' logic to allow mediated devices
>   qemu: namespace: Hook up the discovery of mdevs into the namespace
>     code
>   qemu: Format mdevs on the qemu command line
>   test: Add some test cases for our test suite regarding the mdevs
>   docs: Document the new hostdev device type 'mdev'
> 
>  docs/formatdomain.html.in                          |  40 ++-
>  docs/schemas/domaincommon.rng                      |  17 +
>  po/POTFILES.in                                     |   1 +
>  src/Makefile.am                                    |   1 +
>  src/conf/domain_conf.c                             |  81 ++++-
>  src/conf/domain_conf.h                             |  10 +
>  src/libvirt_private.syms                           |  19 ++
>  src/qemu/qemu_cgroup.c                             |  35 ++
>  src/qemu/qemu_command.c                            |  49 +++
>  src/qemu/qemu_command.h                            |   5 +
>  src/qemu/qemu_domain.c                             |  13 +
>  src/qemu/qemu_domain_address.c                     |  12 +-
>  src/qemu/qemu_hostdev.c                            |  37 ++
>  src/qemu/qemu_hostdev.h                            |   8 +
>  src/qemu/qemu_hotplug.c                            |   2 +
>  src/security/security_apparmor.c                   |   3 +
>  src/security/security_dac.c                        |  56 +++
>  src/security/security_selinux.c                    |  55 +++
>  src/util/virhostdev.c                              | 179 +++++++++-
>  src/util/virhostdev.h                              |  16 +
>  src/util/virmdev.c                                 | 375 +++++++++++++++++++++
>  src/util/virmdev.h                                 |  85 +++++
>  tests/domaincapsschemadata/full.xml                |   1 +
>  ...qemuxml2argv-hostdev-mdev-unmanaged-no-uuid.xml |  37 ++
>  .../qemuxml2argv-hostdev-mdev-unmanaged.args       |  25 ++
>  .../qemuxml2argv-hostdev-mdev-unmanaged.xml        |  38 +++
>  tests/qemuxml2argvtest.c                           |   6 +
>  .../qemuxml2xmlout-hostdev-mdev-unmanaged.xml      |  41 +++
>  tests/qemuxml2xmltest.c                            |   1 +
>  29 files changed, 1239 insertions(+), 9 deletions(-)
>  create mode 100644 src/util/virmdev.c
>  create mode 100644 src/util/virmdev.h
>  create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-hostdev-mdev-unmanaged-no-uuid.xml
>  create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-hostdev-mdev-unmanaged.args
>  create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-hostdev-mdev-unmanaged.xml
>  create mode 100644 tests/qemuxml2xmloutdata/qemuxml2xmlout-hostdev-mdev-unmanaged.xml
> 

I'm no expert in mdevs, but from code POV these look solid.

Michal