Re: nmdm issues with bhyve

Hello.

In short words,what's nmdm used for ? thanks.

On Tue, Jul 16, 2024 at 4:39 PM Polarian <polarian@polarian.dev> wrote:

> Hello,
>
> Over the last few days I have been trying to get nmdm working with
> bhyve. I have discussed it within #bhyve over on libera.chat however
> none of the suggestions so far have fixed the problem, therefore I am
> bringing it to the mailing list for further support.
>
> A rundown what I have done so far, I have a shell script with the
> following contents:
>
> #!/bin/sh
>
> bhyve -c 1 -m 1G -u -H \
>         -s 0,amd_hostbridge \
>         -s 3,ahci-hd,/path/to/install.img \
>         -s 4,virtio-blk,/dev/zvol/zpool-storage/dns \
>         -s 5,virtio-net,tap0 \
>         -s 31,lpc -l com1,/dev/nmdm3A \
>         -l bootrom,/usr/local/share/uefi-firmware/BHYVE_UEFI.fd \
>         dns
>
> To verify the virtual machine was in fact booting, I did test stdio,
> and the install medium for OpenBSD does successfully boot.
>
> The problem, well there is many. Following the FAQ entry [1], the
> following flag is suggested:
>
> -s 31,lpc -l com1,nmdm0A
>
> (where 0 can be substituted to prevent collisions)
>
> Enter problem #1, when I try this by executing the script (with doas,
> doas sh dns.sh) I get the following:
>
> Unable to initialize backend 'nmdm3A' for LPC device com1
> Device emulation initialization error: No such file or directory
>
> Now, both vmm and nmdm have been loaded, checked with the following
> commands:
>
> kldstat | grep vmm
> kldstat | grep nmdm
>
> And these have been entered into /boot/loader.conf see below:
>
> vmm_load="YES"
> nmdm_load="YES"
>
> So they have been loaded into the kernel.
>
> When looking into the problem I found an article on the FreeBSD forums
> which has the same error [2], which would suggest the example in the
> FAQ is either wrong, or deprecated and no longer works.
>
> The solution from this article is to ensure to specify the /dev path, as
> seen in the full script at the beginning of the email, /dev/nmdm0A,
> this DOES work and the vm does startup.
>
> Problem #2, the device doesn't show up, even though the vm is, in fact,
> running.
>
> ls /dev | grep nmdm
>
> The above returns nothing, there is no nmdm device. I have tested it to
> ensure nmdm is in fact working, using cu to open both A and B and
> verifying that the data is being passes between them. So nmdm is
> working!
>
> AllanJude on IRC suggested that I change from 0 to some other number in
> case of conflicts, and so I did (as seen in the script at the beginning
> of the email) changing 0 --> 3, same issue remains.
>
> I can find no further information on this issue, and I am out of ideas,
> so if anyone has nmdm successfully working, could you give me a hand in
> getting it to work on my server?
>
> The FAQ [1] also suggested pty can be used, or a terminal multiplexer
> such as tmux, however I am yet to find any examples on how this could
> be done to substitute nmdm. If anyone has some useful links to some
> examples for these, that would be great!
>
> Thank you,
> --
> Polarian
> GPG signature: 0770E5312238C760
> Jabber/XMPP: polarian@icebound.dev
>
> [1]
>
> https://wiki.freebsd.org/bhyve#Q:_Does_bhyve_have_an_.22out-of-band.22.2F.22lights-out_management.22_serial_console.3F
> [2]
>
> https://forums.freebsd.org/threads/unable-to-initialize-backend-nmdm0a-for-lpc-device-com1.82177/
>
>

-- 
Mario.