Re: [libvirt PATCH v2 1/3] conf: Add support for vDPA network devices

[Laine Stump <laine@xxxxxxxxxx>]

On 9/2/20 3:25 PM, Jonathon Jongsma wrote:
> This patch adds new schema and adds support for parsing and formatting
> domain configurations that include vdpa devices.
>
> 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.
>
> When a device on the host is bound to an appropriate vendor-specific
> driver, it 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='vdpa'.
>
> Signed-off-by: Jonathon Jongsma <jjongsma@xxxxxxxxxx>
> ---
>   docs/formatdomain.rst                 | 23 +++++++++++++++++++
>   docs/schemas/domaincommon.rng         | 15 ++++++++++++
>   src/conf/domain_conf.c                | 32 ++++++++++++++++++++++++++
>   src/conf/domain_conf.h                |  4 ++++
>   src/conf/netdev_bandwidth_conf.c      |  1 +
>   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/qemu/qemu_command.c               |  3 +++
>   src/qemu/qemu_domain.c                |  4 +++-
>   src/qemu/qemu_hotplug.c               |  3 +++
>   src/qemu/qemu_interface.c             |  2 ++
>   src/qemu/qemu_process.c               |  1 +

../src/qemu/qemu_process.c: In function ?qemuProcessNotifyNets?:
../src/qemu/qemu_process.c:3323:9: error: enumeration value 
?VIR_DOMAIN_NET_TYPE_VDPA? not handled in switch [-Werror=switch]
 3323 |         switch (virDomainNetGetActualType(net)) {
      |         ^~~~~~

(this is a switch I recently added and only pushed yesterday, so you 
probably just haven't rebased your branch since then. The VDPA switch in 
this case can be empty)


>   src/qemu/qemu_validate.c              |  1 +
>   src/vmx/vmx.c                         |  1 +
>   tests/qemuxml2argvdata/net-vdpa.xml   | 28 +++++++++++++++++++++++
>   tests/qemuxml2xmloutdata/net-vdpa.xml | 33 +++++++++++++++++++++++++++
>   tests/qemuxml2xmltest.c               |  1 +
>   tools/virsh-domain.c                  |  1 +
>   21 files changed, 159 insertions(+), 1 deletion(-)
>   create mode 100644 tests/qemuxml2argvdata/net-vdpa.xml
>   create mode 100644 tests/qemuxml2xmloutdata/net-vdpa.xml
>
> diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
> index 1979dfb8d3..18d0e28aa1 100644
> --- a/docs/formatdomain.rst
> +++ b/docs/formatdomain.rst
> @@ -4637,6 +4637,29 @@ or stopping the guest.
>      </devices>
>      ...
>   
> +:anchor:`<a id="elementsNICSVDPA"/>`
> +
> +vDPA devices
> +^^^^^^^^^^^^
> +
> +A vDPA network device can be used to provide wire speed network performance within a
> +domain. A vDPA device is a specialized type of network device that uses a
> +datapath that complies with the virtio specification but has a vendor-specific
> +control path. To use such a device with libvirt, the host device must already
> +be bound to the appropriate device-specific vDPA driver. This creates a vDPA
> +char device (e.g.  /dev/vhost-vdpa-0) that can be used to assign the device to
> +a libvirt domain.

You need to have ":since:`Since 6.8.0`" at the end of the paragraph


Also, this isn't the right place for it, but maybe in a knowledgebase 
article we should have more detailed information about what kind of 
hardware is necessary, and how to create the vdpa device by binding the 
vdpa driver, etc. (doesn't need to be produced right away, but shouldn't 
be forgotten about)


> +
> +::
> +
> +   ...
> +   <devices>
> +     <interface type='vdpa'>
> +       <source dev='/dev/vhost-vdpa-0'/>
> +     </interface>
> +   </devices>
> +   ...
> +
>   :anchor:`<a id="elementsTeaming"/>`
>   
>   Teaming a virtio/hostdev NIC pair
> diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
> index a1d6d19e2f..4708e3550f 100644
> --- a/docs/schemas/domaincommon.rng
> +++ b/docs/schemas/domaincommon.rng
> @@ -3111,6 +3111,21 @@
>               <ref name="interface-options"/>
>             </interleave>
>           </group>
> +
> +        <group>
> +          <attribute name="type">
> +            <value>vdpa</value>
> +          </attribute>
> +          <interleave>
> +            <element name="source">
> +              <attribute name="dev">
> +                <ref name="deviceName"/>
> +              </attribute>
> +            </element>
> +            <ref name="interface-options"/>
> +          </interleave>
> +        </group>
> +
>         </choice>
>         <optional>
>           <attribute name="trustGuestRxFilters">
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 72ac4f4191..dbabbbe900 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -550,6 +550,7 @@ VIR_ENUM_IMPL(virDomainNet,
>                 "direct",
>                 "hostdev",
>                 "udp",
> +              "vdpa",
>   );
>   
>   VIR_ENUM_IMPL(virDomainNetModel,
> @@ -2502,6 +2503,10 @@ virDomainNetDefClear(virDomainNetDefPtr def)
>           def->data.vhostuser = NULL;
>           break;
>   
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
> +        VIR_FREE(def->data.vdpa.devicepath);
> +        break;
> +
>       case VIR_DOMAIN_NET_TYPE_SERVER:
>       case VIR_DOMAIN_NET_TYPE_CLIENT:
>       case VIR_DOMAIN_NET_TYPE_MCAST:
> @@ -12036,6 +12041,7 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
>       g_autofree char *vhost_path = NULL;
>       g_autofree char *teamingType = NULL;
>       g_autofree char *teamingPersistent = NULL;
> +    g_autofree char *vdpa_dev = NULL;

I think it's okay to just use the existing char *dev, since that is also 
used for <source dev='blah'/> (of type='direct' devices).

>       const char *prefix = xmlopt ? xmlopt->config.netPrefix : NULL;
>   
>       if (!(def = virDomainNetDefNew(xmlopt)))
> @@ -12129,6 +12135,10 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
>                   if (virDomainChrSourceReconnectDefParseXML(&reconnect, cur, ctxt) < 0)
>                       goto error;
>   
> +            } else if (!vdpa_dev
> +                       && def->type == VIR_DOMAIN_NET_TYPE_VDPA
> +                       && virXMLNodeNameEqual(cur, "source")) {
> +                vdpa_dev = virXMLPropString(cur, "dev");
>               } else if (!def->virtPortProfile
>                          && virXMLNodeNameEqual(cur, "virtualport")) {
>                   if (def->type == VIR_DOMAIN_NET_TYPE_NETWORK) {
> @@ -12386,6 +12396,16 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
>           }
>           break;
>   
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
> +        if (vdpa_dev == NULL) {
> +            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                           _("No <source> 'dev' attribute "
> +                             "specified with <interface type='vdpa'/>"));
> +            goto error;
> +        }
> +        def->data.vdpa.devicepath = g_steal_pointer(&vdpa_dev);
> +        break;
> +
>       case VIR_DOMAIN_NET_TYPE_BRIDGE:
>           if (bridge == NULL) {
>               virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> @@ -12775,6 +12795,7 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
>           case VIR_DOMAIN_NET_TYPE_DIRECT:
>           case VIR_DOMAIN_NET_TYPE_HOSTDEV:
>           case VIR_DOMAIN_NET_TYPE_UDP:
> +        case VIR_DOMAIN_NET_TYPE_VDPA:
>               break;
>           case VIR_DOMAIN_NET_TYPE_LAST:
>           default:
> @@ -26881,6 +26902,14 @@ virDomainNetDefFormat(virBufferPtr buf,
>               }
>               break;
>   
> +        case VIR_DOMAIN_NET_TYPE_VDPA:
> +           if (def->data.vdpa.devicepath) {
> +               virBufferEscapeString(buf, "<source dev='%s'",
> +                                     def->data.vdpa.devicepath);
> +               sourceLines++;
> +           }
> +            break;
> +
>           case VIR_DOMAIN_NET_TYPE_USER:
>           case VIR_DOMAIN_NET_TYPE_LAST:
>               break;
> @@ -31094,6 +31123,7 @@ virDomainNetGetActualVirtPortProfile(const virDomainNetDef *iface)
>       case VIR_DOMAIN_NET_TYPE_MCAST:
>       case VIR_DOMAIN_NET_TYPE_INTERNAL:
>       case VIR_DOMAIN_NET_TYPE_UDP:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>       case VIR_DOMAIN_NET_TYPE_LAST:
>       default:
>           return NULL;
> @@ -31926,6 +31956,7 @@ virDomainNetTypeSharesHostView(const virDomainNetDef *net)
>       case VIR_DOMAIN_NET_TYPE_INTERNAL:
>       case VIR_DOMAIN_NET_TYPE_HOSTDEV:
>       case VIR_DOMAIN_NET_TYPE_UDP:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>       case VIR_DOMAIN_NET_TYPE_LAST:
>           break;
>       }
> @@ -32190,6 +32221,7 @@ virDomainNetDefActualToNetworkPort(virDomainDefPtr dom,
>       case VIR_DOMAIN_NET_TYPE_UDP:
>       case VIR_DOMAIN_NET_TYPE_USER:
>       case VIR_DOMAIN_NET_TYPE_VHOSTUSER:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>           virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
>                          _("Unexpected network port type %s"),
>                          virDomainNetTypeToString(virDomainNetGetActualType(iface)));
> diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
> index 14a376350c..1a1caad96d 100644
> --- a/src/conf/domain_conf.h
> +++ b/src/conf/domain_conf.h
> @@ -875,6 +875,7 @@ typedef enum {
>       VIR_DOMAIN_NET_TYPE_DIRECT,
>       VIR_DOMAIN_NET_TYPE_HOSTDEV,
>       VIR_DOMAIN_NET_TYPE_UDP,
> +    VIR_DOMAIN_NET_TYPE_VDPA,
>   
>       VIR_DOMAIN_NET_TYPE_LAST
>   } virDomainNetType;
> @@ -1048,6 +1049,9 @@ struct _virDomainNetDef {
>                */
>               virDomainActualNetDefPtr actual;
>           } network;
> +        struct {
> +            char *devicepath;
> +        } vdpa;
>           struct {
>               char *brname;
>           } bridge;
> diff --git a/src/conf/netdev_bandwidth_conf.c b/src/conf/netdev_bandwidth_conf.c
> index 396ac62019..4eb12e2951 100644
> --- a/src/conf/netdev_bandwidth_conf.c
> +++ b/src/conf/netdev_bandwidth_conf.c
> @@ -315,6 +315,7 @@ bool virNetDevSupportsBandwidth(virDomainNetType type)
>       case VIR_DOMAIN_NET_TYPE_UDP:
>       case VIR_DOMAIN_NET_TYPE_INTERNAL:
>       case VIR_DOMAIN_NET_TYPE_HOSTDEV:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>       case VIR_DOMAIN_NET_TYPE_LAST:
>           break;
>       }
> diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
> index befd5eb965..23f1cb213e 100644
> --- a/src/libxl/libxl_conf.c
> +++ b/src/libxl/libxl_conf.c
> @@ -1378,6 +1378,7 @@ libxlMakeNic(virDomainDefPtr def,
>           case VIR_DOMAIN_NET_TYPE_INTERNAL:
>           case VIR_DOMAIN_NET_TYPE_DIRECT:
>           case VIR_DOMAIN_NET_TYPE_HOSTDEV:
> +        case VIR_DOMAIN_NET_TYPE_VDPA:
>           case VIR_DOMAIN_NET_TYPE_LAST:
>               virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
>                       _("unsupported interface type %s"),
> diff --git a/src/libxl/xen_common.c b/src/libxl/xen_common.c
> index 56702a2a76..183b09671a 100644
> --- a/src/libxl/xen_common.c
> +++ b/src/libxl/xen_common.c
> @@ -1792,6 +1792,7 @@ xenFormatNet(virConnectPtr conn,
>       case VIR_DOMAIN_NET_TYPE_HOSTDEV:
>       case VIR_DOMAIN_NET_TYPE_UDP:
>       case VIR_DOMAIN_NET_TYPE_USER:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>           virReportError(VIR_ERR_CONFIG_UNSUPPORTED, _("Unsupported net type '%s'"),
>                          virDomainNetTypeToString(net->type));
>           return -1;
> diff --git a/src/lxc/lxc_controller.c b/src/lxc/lxc_controller.c
> index 0a496fb788..be7cc7cb11 100644
> --- a/src/lxc/lxc_controller.c
> +++ b/src/lxc/lxc_controller.c
> @@ -422,6 +422,7 @@ static int virLXCControllerGetNICIndexes(virLXCControllerPtr ctrl)
>           case VIR_DOMAIN_NET_TYPE_UDP:
>           case VIR_DOMAIN_NET_TYPE_INTERNAL:
>           case VIR_DOMAIN_NET_TYPE_HOSTDEV:
> +        case VIR_DOMAIN_NET_TYPE_VDPA:
>               virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
>                              _("Unsupported net type %s"),
>                              virDomainNetTypeToString(actualType));
> diff --git a/src/lxc/lxc_driver.c b/src/lxc/lxc_driver.c
> index a530488dd2..4d3c5d9f63 100644
> --- a/src/lxc/lxc_driver.c
> +++ b/src/lxc/lxc_driver.c
> @@ -3504,6 +3504,7 @@ lxcDomainAttachDeviceNetLive(virLXCDriverPtr driver,
>       case VIR_DOMAIN_NET_TYPE_INTERNAL:
>       case VIR_DOMAIN_NET_TYPE_HOSTDEV:
>       case VIR_DOMAIN_NET_TYPE_UDP:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>           virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
>                          _("Network device type is not supported"));
>           goto cleanup;
> @@ -3558,6 +3559,7 @@ lxcDomainAttachDeviceNetLive(virLXCDriverPtr driver,
>           case VIR_DOMAIN_NET_TYPE_INTERNAL:
>           case VIR_DOMAIN_NET_TYPE_HOSTDEV:
>           case VIR_DOMAIN_NET_TYPE_UDP:
> +        case VIR_DOMAIN_NET_TYPE_VDPA:
>           case VIR_DOMAIN_NET_TYPE_LAST:
>           default:
>               /* no-op */
> @@ -3999,6 +4001,7 @@ lxcDomainDetachDeviceNetLive(virDomainObjPtr vm,
>       case VIR_DOMAIN_NET_TYPE_INTERNAL:
>       case VIR_DOMAIN_NET_TYPE_HOSTDEV:
>       case VIR_DOMAIN_NET_TYPE_UDP:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>           virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
>                          _("Only bridged veth devices can be detached"));
>           goto cleanup;
> diff --git a/src/lxc/lxc_process.c b/src/lxc/lxc_process.c
> index 16969dbf33..d103ec6666 100644
> --- a/src/lxc/lxc_process.c
> +++ b/src/lxc/lxc_process.c
> @@ -606,6 +606,7 @@ virLXCProcessSetupInterfaces(virLXCDriverPtr driver,
>           case VIR_DOMAIN_NET_TYPE_INTERNAL:
>           case VIR_DOMAIN_NET_TYPE_LAST:
>           case VIR_DOMAIN_NET_TYPE_HOSTDEV:
> +        case VIR_DOMAIN_NET_TYPE_VDPA:
>               virReportError(VIR_ERR_INTERNAL_ERROR,
>                              _("Unsupported network type %s"),
>                              virDomainNetTypeToString(type));
> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> index bd98b0a97c..7b7176eb72 100644
> --- a/src/qemu/qemu_command.c
> +++ b/src/qemu/qemu_command.c
> @@ -3691,6 +3691,7 @@ qemuBuildHostNetStr(virDomainNetDefPtr net,
>               return NULL;
>           break;
>   
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>       case VIR_DOMAIN_NET_TYPE_HOSTDEV:
>           /* Should have been handled earlier via PCI/USB hotplug code. */
>       case VIR_DOMAIN_NET_TYPE_LAST:
> @@ -8107,6 +8108,7 @@ qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
>       case VIR_DOMAIN_NET_TYPE_MCAST:
>       case VIR_DOMAIN_NET_TYPE_INTERNAL:
>       case VIR_DOMAIN_NET_TYPE_UDP:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>       case VIR_DOMAIN_NET_TYPE_LAST:
>           /* nada */
>           break;
> @@ -8143,6 +8145,7 @@ qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
>       case VIR_DOMAIN_NET_TYPE_UDP:
>       case VIR_DOMAIN_NET_TYPE_INTERNAL:
>       case VIR_DOMAIN_NET_TYPE_HOSTDEV:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>       case VIR_DOMAIN_NET_TYPE_LAST:
>          /* These types don't use a network device on the host, but
>           * instead use some other type of connection to the emulated
> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> index b1884b6c84..680e7d5bf8 100644
> --- a/src/qemu/qemu_domain.c
> +++ b/src/qemu/qemu_domain.c
> @@ -5174,7 +5174,8 @@ qemuDomainDeviceNetDefPostParse(virDomainNetDefPtr net,
>                                   const virDomainDef *def,
>                                   virQEMUCapsPtr qemuCaps)
>   {
> -    if (net->type != VIR_DOMAIN_NET_TYPE_HOSTDEV &&
> +    if (net->type != VIR_DOMAIN_NET_TYPE_VDPA &&
> +        net->type != VIR_DOMAIN_NET_TYPE_HOSTDEV &&
>           !virDomainNetGetModelString(net) &&
>           virDomainNetResolveActualType(net) != VIR_DOMAIN_NET_TYPE_HOSTDEV)
>           net->model = qemuDomainDefaultNetModel(def, qemuCaps);
> @@ -9308,6 +9309,7 @@ qemuDomainNetSupportsMTU(virDomainNetType type)
>       case VIR_DOMAIN_NET_TYPE_DIRECT:
>       case VIR_DOMAIN_NET_TYPE_HOSTDEV:
>       case VIR_DOMAIN_NET_TYPE_UDP:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>       case VIR_DOMAIN_NET_TYPE_LAST:
>           break;
>       }
> diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
> index e2c6e14c2e..78dd5e9f19 100644
> --- a/src/qemu/qemu_hotplug.c
> +++ b/src/qemu/qemu_hotplug.c
> @@ -1340,6 +1340,7 @@ qemuDomainAttachNetDevice(virQEMUDriverPtr driver,
>       case VIR_DOMAIN_NET_TYPE_MCAST:
>       case VIR_DOMAIN_NET_TYPE_INTERNAL:
>       case VIR_DOMAIN_NET_TYPE_UDP:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>       case VIR_DOMAIN_NET_TYPE_LAST:
>           virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
>                          _("hotplug of interface type of %s is not implemented yet"),
> @@ -3389,6 +3390,7 @@ qemuDomainChangeNetFilter(virDomainObjPtr vm,
>       case VIR_DOMAIN_NET_TYPE_DIRECT:
>       case VIR_DOMAIN_NET_TYPE_HOSTDEV:
>       case VIR_DOMAIN_NET_TYPE_UDP:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>           virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
>                          _("filters not supported on interfaces of type %s"),
>                          virDomainNetTypeToString(virDomainNetGetActualType(newdev)));
> @@ -3726,6 +3728,7 @@ qemuDomainChangeNet(virQEMUDriverPtr driver,
>   
>           case VIR_DOMAIN_NET_TYPE_VHOSTUSER:
>           case VIR_DOMAIN_NET_TYPE_HOSTDEV:
> +        case VIR_DOMAIN_NET_TYPE_VDPA:
>               virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
>                              _("unable to change config on '%s' network type"),
>                              virDomainNetTypeToString(newdev->type));
> diff --git a/src/qemu/qemu_interface.c b/src/qemu/qemu_interface.c
> index 10a87a2528..33157dbbed 100644
> --- a/src/qemu/qemu_interface.c
> +++ b/src/qemu/qemu_interface.c
> @@ -118,6 +118,7 @@ qemuInterfaceStartDevice(virDomainNetDefPtr net)
>       case VIR_DOMAIN_NET_TYPE_UDP:
>       case VIR_DOMAIN_NET_TYPE_INTERNAL:
>       case VIR_DOMAIN_NET_TYPE_HOSTDEV:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>       case VIR_DOMAIN_NET_TYPE_LAST:
>           /* these types all require no action */
>           break;
> @@ -203,6 +204,7 @@ qemuInterfaceStopDevice(virDomainNetDefPtr net)
>       case VIR_DOMAIN_NET_TYPE_UDP:
>       case VIR_DOMAIN_NET_TYPE_INTERNAL:
>       case VIR_DOMAIN_NET_TYPE_HOSTDEV:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>       case VIR_DOMAIN_NET_TYPE_LAST:
>           /* these types all require no action */
>           break;
> diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
> index cfe09d6326..e56e3bf449 100644
> --- a/src/qemu/qemu_process.c
> +++ b/src/qemu/qemu_process.c
> @@ -7531,6 +7531,7 @@ void qemuProcessStop(virQEMUDriverPtr driver,
>           case VIR_DOMAIN_NET_TYPE_INTERNAL:
>           case VIR_DOMAIN_NET_TYPE_HOSTDEV:
>           case VIR_DOMAIN_NET_TYPE_UDP:
> +        case VIR_DOMAIN_NET_TYPE_VDPA:
>           case VIR_DOMAIN_NET_TYPE_LAST:
>               /* No special cleanup procedure for these types. */
>               break;
> diff --git a/src/qemu/qemu_validate.c b/src/qemu/qemu_validate.c
> index 070f1c962b..25f7866e5c 100644
> --- a/src/qemu/qemu_validate.c
> +++ b/src/qemu/qemu_validate.c
> @@ -1145,6 +1145,7 @@ qemuValidateNetSupportsCoalesce(virDomainNetType type)
>       case VIR_DOMAIN_NET_TYPE_MCAST:
>       case VIR_DOMAIN_NET_TYPE_INTERNAL:
>       case VIR_DOMAIN_NET_TYPE_UDP:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>       case VIR_DOMAIN_NET_TYPE_LAST:
>           break;
>       }
> diff --git a/src/vmx/vmx.c b/src/vmx/vmx.c
> index 4b1b04c6e1..6e0fd61f60 100644
> --- a/src/vmx/vmx.c
> +++ b/src/vmx/vmx.c
> @@ -3833,6 +3833,7 @@ virVMXFormatEthernet(virDomainNetDefPtr def, int controller,
>         case VIR_DOMAIN_NET_TYPE_DIRECT:
>         case VIR_DOMAIN_NET_TYPE_HOSTDEV:
>         case VIR_DOMAIN_NET_TYPE_UDP:
> +      case VIR_DOMAIN_NET_TYPE_VDPA:
>           virReportError(VIR_ERR_CONFIG_UNSUPPORTED, _("Unsupported net type '%s'"),
>                          virDomainNetTypeToString(def->type));
>           return -1;
> diff --git a/tests/qemuxml2argvdata/net-vdpa.xml b/tests/qemuxml2argvdata/net-vdpa.xml
> new file mode 100644
> index 0000000000..30cca7eb6e
> --- /dev/null
> +++ b/tests/qemuxml2argvdata/net-vdpa.xml
> @@ -0,0 +1,28 @@
> +<domain type='qemu'>
> +  <name>QEMUGuest1</name>
> +  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
> +  <memory unit='KiB'>219136</memory>
> +  <currentMemory unit='KiB'>219136</currentMemory>
> +  <vcpu placement='static'>1</vcpu>
> +  <os>
> +    <type arch='i686' machine='pc'>hvm</type>
> +    <boot dev='hd'/>
> +  </os>
> +  <clock offset='utc'/>
> +  <on_poweroff>destroy</on_poweroff>
> +  <on_reboot>restart</on_reboot>
> +  <on_crash>destroy</on_crash>
> +  <devices>
> +    <emulator>/usr/bin/qemu-system-i386</emulator>
> +    <controller type='usb' index='0'/>
> +    <controller type='ide' index='0'/>
> +    <controller type='pci' index='0' model='pci-root'/>
> +    <interface type='vdpa'>
> +      <mac address='52:54:00:95:db:c0'/>
> +      <source dev='/dev/vhost-vdpa-0'/>
> +    </interface>
> +    <input type='mouse' bus='ps2'/>
> +    <input type='keyboard' bus='ps2'/>
> +    <memballoon model='none'/>
> +  </devices>
> +</domain>
> diff --git a/tests/qemuxml2xmloutdata/net-vdpa.xml b/tests/qemuxml2xmloutdata/net-vdpa.xml
> new file mode 100644
> index 0000000000..bb2782e848
> --- /dev/null
> +++ b/tests/qemuxml2xmloutdata/net-vdpa.xml
> @@ -0,0 +1,33 @@
> +<domain type='qemu'>
> +  <name>QEMUGuest1</name>
> +  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
> +  <memory unit='KiB'>219136</memory>
> +  <currentMemory unit='KiB'>219136</currentMemory>
> +  <vcpu placement='static'>1</vcpu>
> +  <os>
> +    <type arch='i686' machine='pc'>hvm</type>
> +    <boot dev='hd'/>
> +  </os>
> +  <clock offset='utc'/>
> +  <on_poweroff>destroy</on_poweroff>
> +  <on_reboot>restart</on_reboot>
> +  <on_crash>destroy</on_crash>
> +  <devices>
> +    <emulator>/usr/bin/qemu-system-i386</emulator>
> +    <controller type='usb' index='0'>
> +      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
> +    </controller>
> +    <controller type='ide' index='0'>
> +      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
> +    </controller>
> +    <controller type='pci' index='0' model='pci-root'/>
> +    <interface type='vdpa'>
> +      <mac address='52:54:00:95:db:c0'/>
> +      <source dev='/dev/vhost-vdpa-0'/>
> +      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
> +    </interface>
> +    <input type='mouse' bus='ps2'/>
> +    <input type='keyboard' bus='ps2'/>
> +    <memballoon model='none'/>
> +  </devices>
> +</domain>
> diff --git a/tests/qemuxml2xmltest.c b/tests/qemuxml2xmltest.c
> index 6eb008c8d2..a2601d045e 100644
> --- a/tests/qemuxml2xmltest.c
> +++ b/tests/qemuxml2xmltest.c
> @@ -497,6 +497,7 @@ mymain(void)
>       DO_TEST("net-mtu", NONE);
>       DO_TEST("net-coalesce", NONE);
>       DO_TEST("net-many-models", NONE);
> +    DO_TEST("net-vdpa", NONE);
>   
>       DO_TEST("serial-tcp-tlsx509-chardev", NONE);
>       DO_TEST("serial-tcp-tlsx509-chardev-notls", NONE);
> diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
> index 36581d2c31..7949acff09 100644
> --- a/tools/virsh-domain.c
> +++ b/tools/virsh-domain.c
> @@ -1006,6 +1006,7 @@ cmdAttachInterface(vshControl *ctl, const vshCmd *cmd)
>       case VIR_DOMAIN_NET_TYPE_CLIENT:
>       case VIR_DOMAIN_NET_TYPE_MCAST:
>       case VIR_DOMAIN_NET_TYPE_UDP:
> +    case VIR_DOMAIN_NET_TYPE_VDPA:
>       case VIR_DOMAIN_NET_TYPE_INTERNAL:
>       case VIR_DOMAIN_NET_TYPE_LAST:
>           vshError(ctl, _("No support for %s in command 'attach-interface'"),

Reviewed-by: Laine Stump <laine@xxxxxxxxxx>

with the build error fixed and the "since" line added to the 
formatdomain.rst. Whether or not to conflate char *dev and char 
*vdpa_dev is optional, depending on your opinion, and a more detailed 
knowledgebase article might make more sense after being able to actually 
try it out on some real hardware :-)