[libvirt PATCH v5 0/6] Add support for vDPA network devices

[Laine Stump]

On 10/14/20 1:08 PM, Jonathon Jongsma wrote:
> vDPA network devices allow high-performance networking in a virtual machine by
> providing a wire-speed data path. These devices require a vendor-specific host
> driver but the data path follows the virtio specification.
> 
> The support for vDPA devices was recently added to qemu. This allows
> libvirt to support these devices. This patchset requires that the device is
> configured on the host with the appropriate vendor-specific driver.  This will
> create a chardev on the host at e.g. /dev/vhost-vdpa-0. That chardev path can
> then be used to define a new interface with type=3D'vdpa'.
> 
> Note that in order for hot-unplug to work properly, you may need to apply a
> qemu patch[1] for now. Without the patch, qemu will not close the fd properly
> and any subsequent attempts to use the vdpa chardev will fail like this:
> 
>      virsh # attach-device guest1 vdpa.xml
>      error: Failed to attach device from vdpa.xml
>      error: Unable to open '/dev/vhost-vdpa-0' for vdpa device: Device or reso=
> urce busy
> 
> [1] https://lists.nongnu.org/archive/html/qemu-devel/2020-09/msg06374.html
> 
> Changes in v5:
>   - rebased to latest master
>   - fixed a case where qemuDomainObjExitMonitor() was not called on an error p=
> ath
>   - Improved the nodedev xml. It now includes the path to the chardev in /dev
>     - also updated the nodedev xml schema
>   - added sample nodedev-dumpxml output to the commit message of patch #6
> 
> Jonathon Jongsma (6):
>    conf: Add support for vDPA network devices
>    qemu: add vhost-vdpa capability
>    qemu: add vdpa support
>    qemu: add monitor functions for handling file descriptors
>    qemu: support hotplug of vdpa devices
>    Include vdpa devices in node device list

Reviewed-by: Laine Stump <laine at redhat.com> for 1-5

For patch 6 (the nodedev XML additions) I'm holding off on that in case 
anyone has an opinion on changes that should be made there (you had 
expressed some concern about it in IRC) (HINT HINT!!! ANY TAKERS?)

I've done CI testing with all the patches, and am pushing 1-5 now, which 
will hopefully encourage wider testing among people with real hardware 
that's capable of VDPA.



> 
>   docs/formatdomain.rst                         |  24 +++
>   docs/formatnode.html.in                       |   9 +
>   docs/schemas/domaincommon.rng                 |  15 ++
>   docs/schemas/nodedev.rng                      |  10 +
>   include/libvirt/libvirt-nodedev.h             |   1 +
>   src/conf/domain_conf.c                        |  31 ++++
>   src/conf/domain_conf.h                        |   4 +
>   src/conf/netdev_bandwidth_conf.c              |   1 +
>   src/conf/node_device_conf.c                   |  14 ++
>   src/conf/node_device_conf.h                   |  11 +-
>   src/conf/virnodedeviceobj.c                   |   4 +-
>   src/libxl/libxl_conf.c                        |   1 +
>   src/libxl/xen_common.c                        |   1 +
>   src/lxc/lxc_controller.c                      |   1 +
>   src/lxc/lxc_driver.c                          |   3 +
>   src/lxc/lxc_process.c                         |   1 +
>   src/node_device/node_device_udev.c            |  53 ++++++
>   src/qemu/qemu_capabilities.c                  |   2 +
>   src/qemu/qemu_capabilities.h                  |   1 +
>   src/qemu/qemu_command.c                       |  36 +++-
>   src/qemu/qemu_command.h                       |   3 +-
>   src/qemu/qemu_domain.c                        |   6 +-
>   src/qemu/qemu_hotplug.c                       |  75 +++++++-
>   src/qemu/qemu_interface.c                     |  25 +++
>   src/qemu/qemu_interface.h                     |   2 +
>   src/qemu/qemu_migration.c                     |  10 +-
>   src/qemu/qemu_monitor.c                       |  93 ++++++++++
>   src/qemu/qemu_monitor.h                       |  41 +++++
>   src/qemu/qemu_monitor_json.c                  | 173 ++++++++++++++++++
>   src/qemu/qemu_monitor_json.h                  |  12 ++
>   src/qemu/qemu_process.c                       |   2 +
>   src/qemu/qemu_validate.c                      |  15 ++
>   src/vmx/vmx.c                                 |   1 +
>   .../caps_5.1.0.x86_64.xml                     |   1 +
>   .../caps_5.2.0.x86_64.xml                     |   1 +
>   tests/qemuhotplugmock.c                       |   9 +
>   tests/qemuhotplugtest.c                       |  16 ++
>   .../qemuhotplug-interface-vdpa.xml            |   4 +
>   .../qemuhotplug-base-live+interface-vdpa.xml  |  57 ++++++
>   .../net-vdpa.x86_64-latest.args               |  38 ++++
>   tests/qemuxml2argvdata/net-vdpa.xml           |  28 +++
>   tests/qemuxml2argvmock.c                      |  11 +-
>   tests/qemuxml2argvtest.c                      |   1 +
>   tests/qemuxml2xmloutdata/net-vdpa.xml         |  34 ++++
>   tests/qemuxml2xmltest.c                       |   1 +
>   tools/virsh-domain.c                          |   1 +
>   tools/virsh-nodedev.c                         |   3 +
>   47 files changed, 870 insertions(+), 16 deletions(-)
>   create mode 100644 tests/qemuhotplugtestdevices/qemuhotplug-interface-vdpa.x=
> ml
>   create mode 100644 tests/qemuhotplugtestdomains/qemuhotplug-base-live+interf=
> ace-vdpa.xml
>   create mode 100644 tests/qemuxml2argvdata/net-vdpa.x86_64-latest.args
>   create mode 100644 tests/qemuxml2argvdata/net-vdpa.xml
>   create mode 100644 tests/qemuxml2xmloutdata/net-vdpa.xml
> 
> --=20
> 2.26.2
>