Re: kern/59165: vio9p(4): expose tag through sysctl or device properties

[Ryota Ozaki <ozaki-r%netbsd.org@localhost>]

On Mon, Mar 10, 2025 at 7:50 AM <campbell+netbsd%mumble.net@localhost> wrote:
>
> >Number:         59165
> >Category:       kern
> >Synopsis:       vio9p(4): expose tag through sysctl or device properties
> >Confidential:   no
> >Severity:       serious
> >Priority:       medium
> >Responsible:    kern-bug-people
> >State:          open
> >Class:          change-request
> >Submitter-Id:   net
> >Arrival-Date:   Sun Mar 09 22:50:00 +0000 2025
> >Originator:     Taylor R Campbell
> >Release:        current, 10, 9, ...
> >Organization:
> The Net9P Mountation
> >Environment:
> >Description:
> In virtio-9p, the host passes a tag identifying each possible 9p mount point to the guest.  The mount tag is an arbitrary(?) string configured in the host (e.g., qemu -device virtio-9p-pci,mount_tag=FOO,...).
>
> Currently, NetBSD only prints it to dmesg:
>
> [     1.049667] vio9p0: tagged as FOO
>
> It would be nice if this were exposed to userland via sysctl, device properties, or something, so that, e.g., a devpubd(8) hook could automatically create a symlink for it.
> >How-To-Repeat:
> try to juggle a collection of /dev/vio9pN mount points in the guest and host VM configuration
> >Fix:
> Yes, please!
>

I have a patch for systctl:
https://www.netbsd.org/~ozaki-r/vio9p-tag-sysctl.patch
Does it satisfy the demand?

  ozaki-r