Re: FreeBSD guest on Linux KVM, some vtnet(4) packets don't arrive

> On 10. Apr 2026, at 23:34, Adrian Chadd <[email protected]> wrote:
> 
> On Fri, 10 Apr 2026 at 13:40, Michael Tuexen
> <[email protected]> wrote:
>> 
>>> On 10. Apr 2026, at 12:21, Lexi Winter <[email protected]> wrote:
>>> 
>>> Lexi Winter wrote in <[email protected]>:
>>>> the problem seems to be due to choice of cipher:
>>>> 
>>>> % ssh [email protected] [email protected]
>>>> Fssh_ssh_dispatch_run_fatal: Connection to fd00:0:0:1::b port 22: message authentication code incorrect
>>>> 
>>>> % ssh [email protected] [email protected]
>>>> Last login: Fri Apr 10 08:17:20 2026 from tansy.le-fay.org
>>>> 
>>>> if AES is broken, that would also explain why TLS doesn't work.
>>>> 
>>>> unfortunately while trying to rebuild world i ran into an unrelated
>>>> panic[0], so i'll need to find a workaround for that before i can
>>>> test more.
>>> 
>>> i was able to cross-build current main (82ff1c334b97) on another system
>>> and copy it over, which seems to have fixed the issue with TLS and SSH.
>>> 
>>> i need to do some final setup on the VM and then i'll try to do some
>>> more testing for the original vtnet/tcpdump problem, which is still
>>> present.
>> Hi Ivy,
>> 
>> is this really a vtnet/tcpdump problem? On my PPC64 VM, tcpdump does not
>> show any packets on vtnet0 or lo0. On bare metal, tcpdump does not show
>> any packets on lo0 or bge2.
>> 
>> So I guess, this has nothing to do with vtnet.
> 
> There's likely a bunch of weird broken stuff that we need to fix.
> 
> I'm pretty sure tcpdump worked fine in December last year on
> ppc64le/ppc64be since I was doing
> general fixing of stuff there.
> 
> Let's file some ppc64 bugs and get them triaged/debugged. I bet the
> "why's tcpdump not working?"
> problem is triagable with dtrace/fbt points.
Some more testing:
1. 15.0 shows the same behavior as CURRENT
2. It is not that tcpdump is not working at all, it just shows the
   packets in a batch after some time. Use ping -s 16000 127.0.0.1
   and you see what I mean. Just using ping requires you to wait
   substantially longer.
   So it seems that tcpdump gets the packets on PPC64 only when some
   buffer is full.

Best regards
Michael
> 
> 
> 
> -adrian