Re: domU interface does not remain in xenbr0

[Paul Leiber <paul@xxxxxxxxxxxxxxxx>]

Hi Andrew,

This issue seems to be caused by the FreeBSD netfront driver and a 
recent netback change. There is a similar description here:
https://forum.opnsense.org/index.php?topic=28708.0

Downgrading the dom0 linux kernel helped in some cases.

There is a patch which needs review:

https://reviews.freebsd.org/D33876

Best regards,

Paul

Am 17.06.2022 um 23:50 schrieb Andrew Klassen:
> I have installed a Freebsd guest using hvm in xen running on Debian 10 
> and have the xenbr0 bridge configured at boot using network/interfaces 
> file.
> I am having trouble getting my guest to boot into multiuser mode and 
> believe it has something to do
> with my nic driver (xn). In single user mode, I can configure an IP 
> address and ping the host bridge.
> Doing troubleshooting is difficult because the vif on the host won’t 
> stay assigned as a port in the xenbr0
> bridge.
>
> I do “brctl show” and the interface isn’t a member so I do “brctl 
> addif” and it assigned. Then I can do my ping
> Etc.. but soon afterwards it gets removed by some software that is 
> running. Not sure if it is the hypervisor or what.
> I can see messages in /var/log/messages but there is output in 
> xenstored-access.log.
> Even when I am not doing anything on the host or on the guest. It just 
> gets removed.
> The other thought I had was to change the model for the vif to e1000 
> so the system would boot cleanly
> and hopefully have a stable connection. But adding “model=e1000” in 
> the vif configuration of the
> domain’s config file, shutting down, and creating the domain again, 
> doesn’t change the nic driver;
> the guest kernel still sees xn0.  I had seen via on-line search that I 
> can use
> xl set-parameters uuid … platform-nic=e1000
>
> but the program cores. So, I must not be entering the command correctly.
>
> Here is the information I gathered:
>
> root@xen:/etc/xen# xl list -v
>
> Name ID   Mem VCPUs      State   Time(s) 
> UUID                            Reason-Code   Security Label
> Domain-0               0 12001     8     r-----   14055.6 
> 00000000-0000-0000-0000-000000000000        -                -
> UCD_t1_Domain 21  4096     4     -b----     113.0 
> a697608c-3e7c-4b08-8aa6-d6125562a25e        -                -
> root@xen:/etc/xen# xl network-list 21
>
> Idx BE Mac Addr.                   handle state evt-ch   
> tx-/rx-ring-ref BE-path
> 0     0   00:16:3e:00:00:11     0      4        13         784/785 
> /local/domain/0/backend/vif/21/0
> root@xen:/etc/xen# brctl show
>
> bridge name     bridge id           STP enabled     interfaces
>
> xenbr0              8000.f28587ae759e no                      eth1
>
> Here is the domain config file:
>
> root@xen:/etc/xen# cat ucd.cfg
>
> arch_libdir= 'lib64'
>
> builder='hvm'
>
> memory=4096
>
> name="UCD_t1_Domain"
>
> vcpus=4
>
> vif = [ 'mac=00:16:3e:00:00:11, bridge=xenbr0, model=e1000' ]
>
> disk = [ '/home/admin/tmp/ucd.img,raw,hda,rw', 
> '/home/admin/tmp/install.iso,raw,hdc:cdrom,r' ]
> on_poweroff = 'destroy'
>
> on_reboot = 'restart'
>
> on_crash = 'preserve'
>
> boot = "cd"
>
> snapshot=1
>
> sdl = 0
>
> vnc = 1
>
> vnclisten="192.168.21.9"
>
> vncpasswd=''
>
> serial='pty'
>
> Here is the vif being removed:
>
> root@xen:/etc/xen# brctl show
>
> bridge name     bridge id               STP enabled     interfaces
>
> xenbr0          8000.f28587ae759e no              eth1
>
> root@xen:/etc/xen# brctl addif xenbr0 vif21.0
>
> root@xen:/etc/xen# brctl show
>
> bridge name     bridge id               STP enabled     interfaces
>
> xenbr0          8000.f28587ae759e no              eth1
>
>                             vif21.0
>
> -------------- var/log/messages
>
> Jun 17 16:30:35 xen kernel: [1301259.952042] xenbr0: port 2(vif21.0) 
> entered disabled state
> Jun 17 16:30:35 xen kernel: [1301259.952241] device vif21.0 entered 
> promiscuous mode
> Jun 17 16:30:35 xen kernel: [1301259.952335] xenbr0: port 2(vif21.0) 
> entered blocking state
> Jun 17 16:30:35 xen kernel: [1301259.952339] xenbr0: port 2(vif21.0) 
> entered forwarding state
> Jun 17 16:31:24 xen kernel: [1301308.580201] device vif21.0 left 
> promiscuous mode
> Jun 17 16:31:24 xen kernel: [1301308.580270] xenbr0: port 2(vif21.0) 
> entered disabled state
> root@xen:/etc/xen# brctl show
>
> bridge name     bridge id            STP enabled     interfaces
>
> xenbr0              8000.f28587ae759e no                      eth1
>
> Any ideas?
>
> Thanks
>
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