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

> On 10. Apr 2026, at 11:24, Lexi Winter <[email protected]> wrote:
> 
> Lexi Winter wrote in <[email protected]>:
>> 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.
>> 
>> [0] https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=294369
> 
> i attempted to update to latest main to see if this helped debug the ZFS
> issue, and ran into a new issue with vtnet, which is that it now doesn't
> attach at all:
> 
> pci0: <POWER Hypervisor PCI bus> on pcib0
> virtio_pci0: <VirtIO PCI (modern) Network adapter> port 0x20-0x3f mem 0x81030000-0x81030fff,0x210000000000-0x210000003fff irq 4610 at device 2.0 numa-domain 0 on pci0
> vtnet0: <VirtIO Networking Adapter> numa-domain 0 on virtio_pci0
> vtnet0: Invalid max_virtqueue_pairs value: 65535. Multiqueue feature disabled.
> virtio_pci0: virtqueue 1 (vtnet0-tx0) does not exist (size is zero)
> virtio_pci0: cannot allocate virtqueue 1: 19
> vtnet0: cannot allocate virtqueues
> device_attach: vtnet0 attach returned 19
> 
> this must have broken recently (the March 30 snapshot works) so i'll try to
> bisect this.
I guess this is related to
https://cgit.FreeBSD.org/src/commit/?id=0b39d72d0491c77e3e9883015b1fac46663c71de
You can put
hw.virtio.pci.transitional=0
in /boot/loader.conf to get the old behavior. Does that help?

Best regards
Michael