Bhyve tests and findings

Matt Churchyard matt.churchyard at
Fri Aug 5 08:46:48 UTC 2016

> Zitat von Peter Grehan <grehan at>:

> Hi Mike,
>> - Windows 8, 8.1 and 10 installs and runs in graphical mode flawlessly.
>  Have you had any issues with the XHCI mouse on 8/8.1 ?
>> - I was able to graphically Restore/Reconfigure a Acronis 
>> Windows-Backup into a Bhyve instance  using the Acronis Restore-CD 
>> (Converting a BIOS Win8.1 to UEFI Win8.1)
>  Very nice !
>> - Only vnclient from FreeBSD can connect to the bhyve VNC Server.
>>  I havn't found any vncviewer running on Windows which where able to 
>> work (tried UltraVNC, RealVNC, ...)
>  Some VNC clients refuse to connect when only null-auth is advertized 
> by the server. There is a patch to bhyve to support VNC password-auth, 
> which may fix the issue with these clients.

>Yes, that sounds reasonable.

>> - in VNC only most basic Keys work most special characters like (*\@) 
>> (and of course no german localization)  but at least a usual US-kbd 
>> would be helpful.
>>  (Is there a way to debug the keystrokes or duplicate a localized VNC 
>> kbd from some VNC server)
>  Nothing outside of modifying the source, but it seems useful enough 
> to add a parameter for this.
>> - For the SAP-Systems it seems that only 4 disks get used when the 
>> disk type is virtio-blk.
>>  (Is this intentionally or a feature of vm-bhyve? How to provide more
>> disks)
>  I'll let Matt comment on that. There's no limitation with guests that 
> support MSI interrupts for adapters. Unfortunately, Windows guests 
> require legacy interrupts for the AHCI controller, which is where the 
> restriction originates.

>I'd like to use a 6 disks setup with Centos7.
>Centos7 on XEN PVM has no issue with supporting 6 paravirtulized disks.

>Thats the config (for vm-bhyve) where only the first 4 disks are used for the guest (Centos7):


Sorry I didn't actually spot that you were using my vm-bhyve code to run the guest the first time.

The UEFI code in vm-bhyve is currently limited to using slots 4/5/6 for disks so you should only see 3... (I put a CD device on slot 3)
If you look in the /path/to/guest/vm-bhyve.log log file you'll probably see something like "ending disks as disk2 due to UEFI limitations".

I've never been 100% on which guests have the limitation and which don't, so in UEFI mode I played it safe and just used the 3 slots. If you run the guest with the grub loader instead of UEFI you should get all the disks.

If you want, you can comment out the limitation in the vm-bhyve source and see if the guest will pick up the extra disks. It's the 4 lines after the "can't go past slot 6" comment around line 364 of lib/vm-run. If it works it may be worth me adding a configuration option to toggle this limit.

As mentioned in my last email FreeBSD CURRENT (12) now supports up to 32 disks per ahci device, and I've successfully had 8 disks in Windows using just 1 pci slot. This won't be in 11.0 unfortunately (as far as I'm aware) but I hope it gets merged into a future 11 release.


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