Re: Network driver domain broken

[Andrea Stevanato <andrea.stevanato@xxxxxxxxxxxxxxx>]

On 3/7/2022 12:46 PM, Roger Pau Monné wrote:
> On Mon, Mar 07, 2022 at 12:39:22PM +0100, Andrea Stevanato wrote:
>> /local/domain/2 = ""   (n0,r2)
>> /local/domain/2/vm = "/vm/f6dca20a-54bb-43af-9a62-67c55cb75708"   (n0,r2)
>> /local/domain/2/name = "guest1"   (n0,r2)
>> /local/domain/2/cpu = ""   (n0,r2)
>> /local/domain/2/cpu/0 = ""   (n0,r2)
>> /local/domain/2/cpu/0/availability = "online"   (n0,r2)
>> /local/domain/2/cpu/1 = ""   (n0,r2)
>> /local/domain/2/cpu/1/availability = "online"   (n0,r2)
>> /local/domain/2/memory = ""   (n0,r2)
>> /local/domain/2/memory/static-max = "1048576"   (n0,r2)
>> /local/domain/2/memory/target = "1048577"   (n0,r2)
>> /local/domain/2/memory/videoram = "-1"   (n0,r2)
>> /local/domain/2/device = ""   (n0,r2)
>> /local/domain/2/device/suspend = ""   (n0,r2)
>> /local/domain/2/device/suspend/event-channel = ""   (n2)
>> /local/domain/2/device/vif = ""   (n0,r2)
>> /local/domain/2/device/vif/0 = ""   (n2,r1)
>> /local/domain/2/device/vif/0/backend = "/local/domain/1/backend/vif/2/0"
>> (n2,r1)
>> /local/domain/2/device/vif/0/backend-id = "1"   (n2,r1)
>> /local/domain/2/device/vif/0/state = "6"   (n2,r1)
>> /local/domain/2/device/vif/0/handle = "0"   (n2,r1)
>> /local/domain/2/device/vif/0/mac = "00:16:3e:07:df:91"   (n2,r1)
>> /local/domain/2/device/vif/0/xdp-headroom = "0"   (n2,r1)
>> /local/domain/2/control = ""   (n0,r2)
>> /local/domain/2/control/shutdown = ""   (n2)
>> /local/domain/2/control/feature-poweroff = "1"   (n2)
>> /local/domain/2/control/feature-reboot = "1"   (n2)
>> /local/domain/2/control/feature-suspend = ""   (n2)
>> /local/domain/2/control/sysrq = ""   (n2)
>> /local/domain/2/control/platform-feature-multiprocessor-suspend = "1"
>> (n0,r2)
>> /local/domain/2/control/platform-feature-xs_reset_watches = "1"   (n0,r2)
>> /local/domain/2/data = ""   (n2)
>> /local/domain/2/drivers = ""   (n2)
>> /local/domain/2/feature = ""   (n2)
>> /local/domain/2/attr = ""   (n2)
>> /local/domain/2/error = ""   (n2)
>> /local/domain/2/error/device = ""   (n2)
>> /local/domain/2/error/device/vif = ""   (n2)
>> /local/domain/2/error/device/vif/0 = ""   (n2)
>> /local/domain/2/error/device/vif/0/error = "1 allocating event channel"
>> (n2)
> 
> That's the real error. Your guest netfront fails to allocate the event
> channel. Do you get any messages in the guest dmesg after trying to
> attach the network interface?

Just these two lines:

[  389.453390] vif vif-0: 1 allocating event channel
[  389.804135] vif vif-0: 1 allocating event channel
 
> Does the same happen if you don't use a driver domain and run the
> backend in dom0?

No, it does not. On dom0 everything is set up correctly. Here the final
part of xl -vvv devd -F executed on dom0, which is different from the 
execution on guest0

libxl: debug: libxl_event.c:1052:devstate_callback: backend 
/local/domain/0/backend/vif/1/0/state wanted state 2 ok
libxl: debug: libxl_event.c:850:libxl__ev_xswatch_deregister: watch 
w=0xaaaaca342470 wpath=/local/domain/0/backend/vif/1/0/state token=1/2: 
deregister slotnum=1
libxl: debug: libxl_device.c:1090:device_backend_callback: Domain 1:calling 
device_backend_cleanup
libxl: debug: libxl_event.c:864:libxl__ev_xswatch_deregister: watch 
w=0xaaaaca342470: deregister unregistered
libxl: debug: libxl_device.c:1191:device_hotplug: Domain 1:calling hotplug 
script: /etc/xen/scripts/vif-bridge online
libxl: debug: libxl_device.c:1192:device_hotplug: Domain 1:extra args:
libxl: debug: libxl_device.c:1198:device_hotplug: Domain 1:     type_if=vif
libxl: debug: libxl_device.c:1200:device_hotplug: Domain 1:env:
libxl: debug: libxl_device.c:1207:device_hotplug: Domain 1:     script: 
/etc/xen/scripts/vif-bridge
libxl: debug: libxl_device.c:1207:device_hotplug: Domain 1:     XENBUS_TYPE: vif
libxl: debug: libxl_device.c:1207:device_hotplug: Domain 1:     XENBUS_PATH: 
backend/vif/1/0
libxl: debug: libxl_device.c:1207:device_hotplug: Domain 1:     
XENBUS_BASE_PATH: backend
libxl: debug: libxl_device.c:1207:device_hotplug: Domain 1:     netdev:
libxl: debug: libxl_device.c:1207:device_hotplug: Domain 1:     vif: vif1.0
libxl: debug: libxl_aoutils.c:593:libxl__async_exec_start: forking to execute: 
/etc/xen/scripts/vif-bridge online

> 
> Regards, Roger.

Cheers,
Andrea.