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

[Jonathon Jongsma]

On Tue, 20 Oct 2020 15:16:48 -0400
Laine Stump <laine at redhat.com> wrote:

> 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 wouldn't say "concern", necessarily. I just wanted to make sure that
there wasn't a different element name that might be more consistent
with other parts of the XML schema. 

> 
> 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
> >   
>