macvtap with disconnected physical interface

[Gionatan Danti]

Il 2022-05-03 10:31 Daniel P. Berrangé ha scritto:
> Can you share the <interface> configuration for your guest NIC so we
> can see how it is setup.

Here we go...

<interface type='direct'>
   <mac address='xx:xx:xx:xx:xx:xx'/>
   <source dev='enp0s31f6' mode='bridge'/>
   <target dev='macvtap0'/>
   <model type='virtio'/>
   <alias name='net0'/>
   <address type='pci' domain='0x0000' bus='0x01' slot='0x00' 
function='0x0'/>
</interface>

# ifconfig
Both the physical and macvtap interfaces are disconnected (note how 
RUNNING is missing):
enp0s31f6: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
         ether xx:xx:xx:xx:xx:xx  txqueuelen 1000  (Ethernet)
         RX packets 0  bytes 0 (0.0 B)
         RX errors 0  dropped 0  overruns 0  frame 0
         TX packets 0  bytes 0 (0.0 B)
         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
         device interrupt 16  memory 0xf4300000-f4320000
macvtap0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
         ether xx:xx:xx:xx:xx:xx  txqueuelen 500  (Ethernet)
         RX packets 0  bytes 0 (0.0 B)
         RX errors 0  dropped 0  overruns 0  frame 0
         TX packets 0  bytes 0 (0.0 B)
         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

# ip link
2: enp0s31f6: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc 
fq_codel state DOWN mode DEFAULT group default qlen 1000
     link/ether xx:xx:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff
6: macvtap0 at enp0s31f6: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 
qdisc noqueue state LOWERLAYERDOWN mode DEFAULT group default qlen 500
     link/ether xx:xx:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff

I can bring up the macvtap interface with the following command (notice 
the RUNNING/UP flag):
# ip link set macvtap0 protodown off
# ifconfig
macvtap0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
         inet6 fe80::redacted  prefixlen 64  scopeid 0x20<link>
         ether xx:xx:xx:xx:xx:xx  txqueuelen 500  (Ethernet)
         RX packets 0  bytes 0 (0.0 B)
         RX errors 0  dropped 0  overruns 0  frame 0
         TX packets 42  bytes 6001 (6.0 KB)
         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
# ip link
6: macvtap0 at enp0s31f6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc 
noqueue state UP mode DEFAULT group default qlen 500
     link/ether xx:xx:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff

However, at the next connection/disconnection of the physical link, the 
macvtap interface will go down again.

Regards.


-- 
Danti Gionatan
Supporto Tecnico
Assyoma S.r.l. - www.assyoma.it
email: g.danti at assyoma.it - info at assyoma.it
GPG public key ID: FF5F32A8