[libvirt PATCH v5 00/30] Add support for persistent mediated devices

Jonathon Jongsma jjongsma at redhat.com
Tue Mar 2 22:30:35 UTC 2021


This patch series follows the previously-merged series which added support for
transient mediated devices. This series expands mdev support to include
persistent device definitions. Again, it relies on mdevctl as the backend.

It follows the common libvirt pattern of APIs by adding the following new APIs
for node devices:
    - virNodeDeviceDefineXML() - defines a persistent device
    - virNodeDeviceUndefine() - undefines a persistent device
    - virNodeDeviceCreate() - starts a previously-defined device

It also adds virsh commands mapping to these new APIs: nodedev-define,
nodedev-undefine, and nodedev-start.

Since we rely on mdevctl for the definition of mediated devices, we need a way
to stay up-to-date with devices that are defined by mdevctl (outside of
libvirt).  The method for staying up-to-date is currently a little bit crude
due to the fact that mdevctl does not emit any events when new devices are
added or removed. As a workaround, we create a file monitor for the mdevctl
config directory and re-query mdevctl when we detect changes within that
directory. In the future, mdevctl may introduce a more elegant solution.

Changes in v5:
 - Rebase to git master
 - updated new API version info to 7.2.0
 - capture and relay stderr message from mdevctl
 - changed to using GHashTable functions directly instead of deprecated
   virHash functions
 - protected mdevctlMonitors with a mutex
 - added a couple patches to fix the 5s delay when defining a new mdev. These
   are currently separate patches added to the end of the series, but could be
   squashed into the earlier commits if that's preferred.
 - various other minor review fixes

Changes in v4:
 - rebase to git master
 - switch to throwaway thread for querying mdevctl
 - fixed a bug when removing devices because I was accidentally using
   virHashForEach() instead of virHashForeachSafe()
 - use DEFINED/UNDEFINED events instead of STARTED/STOPPED events
 - changes related to merging information about mdev devices from both udev a=
nd
   mdevctl:
   - Re-used the same function to copy extra data from mdevctl regardless of
     whether we're processing a udev event or a mdevctl event (recommended by
     Erik). This results in slightly more complex handling of the object
     lifetimes (see patch 9), but it consolidates some code.
   - nodeDeviceDefCopyFromMdevctl() previously only copied the data that was
     unique to mdevctl and didn't exist in udev. It now copies additional data
     (possibly overwriting some udev).  This solves a problem where a device =
is
     defined but not active (i.e.  we have not gotten any data from udev), and
     then changed (e.g. somebody calls 'mdevctl modify' to change the mdev
     type), but libvirt was not updating to the new definition.
 - fix a bug where we were mistakenly emitting 'update' events for devices th=
at
   had not changed
 - Added the ability to specify a uuid for an mdev via device XML.
 - split some commits into multiple patches
 - updated new API version info to 7.1.0
 - Fixed a bug reported by Yan Fu which hangs the client when attempting to
   destroy a nodedev that is in use by an active vm. See
   https://www.redhat.com/archives/libvir-list/2021-February/msg00116.html for
   solution suggested by Alex.
 - numerous smaller fixes from review findings

changes in v3:
 - streamlined tests -- removed some unnecessary duplication
 - split out patch to factor out node device name generation function
 - split nodeDeviceParseMdevctlChildDevice() into a separate function
 - added follow-up patch to remove space-padded alignment in header
 - refactored the mdevctl update handling significantly:
   - no longer a separate persistent thread that gets signaled by a timer
   - now piggybacks onto the existing udev thread and signals the thread in t=
he
     same way that the udev event does.
   - Daniel suggested spawning a throw-away thread to handle mdevctl updates,
     but that introduces the complexity of possibly serializing multiple
     throw-away threads (e.g. if we get an 'created' event followed immediate=
ly
     by a 'deleted' event, two threads may be spawned and we'd need to ensure
     they are properly ordered)
 - added virNodeDeviceObjListForEach() and virNodeDeviceObjListRemoveLocked()
   to simplify removing devices that are removed from mdevctl.
 - coding style fixes
 - NOTE: per Erik's request, I experimented with changing the way that mdevctl
   commands were generated and tested (e.g. introducing something like
   virMdevctlGetCommand(def, MDEVCTL_COMMAND_<SUBCOMMAND>, ...)), but it was
   too invasive and awkward and didn't seem worthwhile

Changes in v2:
 - rebase to latest git master

Jonathon Jongsma (30):
  nodedev: capture and report stderror from mdevctl
  tests: remove extra trailing semicolon
  nodedev: introduce concept of 'active' node devices
  nodedev: Add ability to filter by active state
  nodedev: fix docs for virConnectListAllNodeDevices()
  nodedev: expose internal helper for naming devices
  nodedev: add ability to parse mdevs from mdevctl
  nodedev: add ability to list defined mdevs
  nodedev: add persistence to virNodeDeviceObj
  nodedev: add DEFINED/UNDEFINED lifecycle events
  nodedev: add mdevctl devices to node device list
  nodedev: add helper functions to remove node devices
  nodedev: handle mdevs that disappear from mdevctl
  nodedev: Refresh mdev devices when changes are detected
  nodedev: add function to generate mdevctl define command
  api: add virNodeDeviceDefineXML()
  virsh: Add --inactive, --all to nodedev-list
  virsh: add nodedev-define command
  nodedev: refactor tests to support mdev undefine
  api: add virNodeDeviceUndefine()
  virsh: Factor out function to find node device
  virsh: add nodedev-undefine command
  api: add virNodeDeviceCreate()
  virsh: add "nodedev-start" command
  nodedev: add <uuid> element to mdev caps
  nodedev: add ability to specify UUID for new mdevs
  nodedev: fix hang when destroying an mdev in use
  nodedev: add docs about mdev attribute order
  nodedev: factor out function to add mediated devices
  nodedev: avoid delay when defining a new mdev

 docs/formatnode.html.in                       |   5 +-
 docs/schemas/nodedev.rng                      |  43 +-
 examples/c/misc/event-test.c                  |   4 +
 include/libvirt/libvirt-nodedev.h             |  20 +-
 src/access/viraccessperm.c                    |   2 +-
 src/access/viraccessperm.h                    |   6 +
 src/conf/node_device_conf.c                   |  14 +
 src/conf/node_device_conf.h                   |   8 +
 src/conf/virnodedeviceobj.c                   | 147 +++-
 src/conf/virnodedeviceobj.h                   |  24 +
 src/driver-nodedev.h                          |  14 +
 src/libvirt-nodedev.c                         | 141 +++-
 src/libvirt_private.syms                      |   6 +
 src/libvirt_public.syms                       |   7 +
 src/node_device/node_device_driver.c          | 743 +++++++++++++++++-
 src/node_device/node_device_driver.h          |  50 +-
 src/node_device/node_device_udev.c            | 217 ++++-
 src/remote/remote_driver.c                    |   3 +
 src/remote/remote_protocol.x                  |  40 +-
 src/remote_protocol-structs                   |  16 +
 src/rpc/gendispatch.pl                        |   1 +
 ...19_36ea_4111_8f0a_8c9a70e21366-define.argv |   2 +
 ...19_36ea_4111_8f0a_8c9a70e21366-define.json |   1 +
 ...019_36ea_4111_8f0a_8c9a70e21366-start.argv |   3 +-
 ...39_495e_4243_ad9f_beb3f14c23d9-define.argv |   1 +
 ...39_495e_4243_ad9f_beb3f14c23d9-define.json |   1 +
 ...16_1ca8_49ac_b176_871d16c13076-define.argv |   1 +
 ...16_1ca8_49ac_b176_871d16c13076-define.json |   1 +
 tests/nodedevmdevctldata/mdevctl-create.argv  |   1 +
 .../mdevctl-list-defined.argv                 |   1 +
 .../mdevctl-list-multiple.json                |  59 ++
 .../mdevctl-list-multiple.out.xml             |  43 +
 .../nodedevmdevctldata/mdevctl-undefine.argv  |   1 +
 tests/nodedevmdevctltest.c                    | 232 +++++-
 ...v_d069d019_36ea_4111_8f0a_8c9a70e21366.xml |   1 +
 tools/virsh-nodedev.c                         | 269 ++++++-
 36 files changed, 1935 insertions(+), 193 deletions(-)
 create mode 100644 tests/nodedevmdevctldata/mdev_d069d019_36ea_4111_8f0a_8c9=
a70e21366-define.argv
 create mode 100644 tests/nodedevmdevctldata/mdev_d069d019_36ea_4111_8f0a_8c9=
a70e21366-define.json
 create mode 100644 tests/nodedevmdevctldata/mdev_d2441d39_495e_4243_ad9f_beb=
3f14c23d9-define.argv
 create mode 100644 tests/nodedevmdevctldata/mdev_d2441d39_495e_4243_ad9f_beb=
3f14c23d9-define.json
 create mode 100644 tests/nodedevmdevctldata/mdev_fedc4916_1ca8_49ac_b176_871=
d16c13076-define.argv
 create mode 100644 tests/nodedevmdevctldata/mdev_fedc4916_1ca8_49ac_b176_871=
d16c13076-define.json
 create mode 100644 tests/nodedevmdevctldata/mdevctl-create.argv
 create mode 100644 tests/nodedevmdevctldata/mdevctl-list-defined.argv
 create mode 100644 tests/nodedevmdevctldata/mdevctl-list-multiple.json
 create mode 100644 tests/nodedevmdevctldata/mdevctl-list-multiple.out.xml
 create mode 100644 tests/nodedevmdevctldata/mdevctl-undefine.argv

--=20
2.26.2





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