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

hello,

Miroslav Lachman wrote in <[email protected]>:
> On 08/04/2026 16:38, Lexi Winter wrote:
> > vtnet0: flags=1008843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,LOWER_UP> metric 0 mtu 1500
> 
> Can you try disabling rxcsum / txcsum? (add  -rxcsum -txcsum to
> ifconfig_vtnet0 in rc.conf)
> I had similar problem in the past on KVM hosted FreeBSD guest and this
> solved the problem for me.

unfortunately i tried disabling tx and rx csum, LRO, and TSO, and this
made no difference (you can see above that those flags are not set on
vtnet0).

but i did notice a new oddity: even for network traffic that works, like
ping to fe80::2 or an IPv4 ping, the traffic doesn't show in tcpdump.
this is not the case on amd64 (main dc752c26b7e5) where tcpdump works
fine on vtnet(4).

so possibly there are two separate issues here.  i'm currently
installing a ppc64le guest, just in case this is an issue with
endian translation on the Linux side.  (the host is ppc64le.)

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