[systemd-devel] How to give users permissions to /dev/kfd

[Mantas Mikulėnas]

On Sat, Oct 14, 2017 at 1:07 AM, Tom Stellard <tstellar at redhat.com> wrote:

> On 10/12/2017 09:04 PM, Mantas Mikulėnas wrote:
> > On Fri, Oct 13, 2017, 00:30 Tom Stellard <tstellar at redhat.com <mailto:
> tstellar at redhat.com>> wrote:
> >
> >     Hi,
> >
> >     The amdkfd kernel driver exposes the /dev/kfd device file for doing
> gpgpu
> >     computing on AMD GPUs, I would like to setup the permissions on this
> device
> >     file, so that regular users can access it.  I think it makes sense to
> >     try to copy what is being done for the other GPU device files, like
> /dev/dri/cardX.
> >     I can see the udev rules for these /dev/dri/cardX, but on my system
> it looks like
> >     something is giving users access to these files using  access
> control lists
> >     (acls), but I'm not sure where the acls are being modified.  Is
> systemd only responsible
> >     for the udev rules or is there something else in systemd I need to
> modify to
> >     get the acls set correctly?
> >
> >
> > udev applies these ACLs to all devices tagged with TAG+="uaccess" from
> udev rules.
> >
> > (The tagging is kind of an internal detail and your rules are supposed
> to use ENV{ID_this_and_that}, but... for personal use it works well enough.)
> >
> > Just make sure you get the rule ordering right, I think
> 71-something.rules is a good place. I can't check right now, might be
> remembering wrong.
> >
>
> Thanks.  I've been experimenting with this, and I noticed that the ACLs are
> not set when I login to the machine via ssh.  Is there something else I
> need
> to do to get these ACLs enabled for ssh sessions?
>

No, it's only available for local sessions (ones which systemd-logind
considers "local" + "active"). I think the idea is that console users
automatically get more privileges in general.

*(To update my last mail, I *think* the actual ACL setting is done by both
udev (when the device first shows up) and systemd-logind (when sessions are
switched).)*

For SSH-only usage, use traditional groups (e.g. add yourself to the
"video" group). To assign group ownership to /dev/kfd, use GROUP="foo" in
udev rules.

-- 
Mantas Mikulėnas <grawity at gmail.com>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/systemd-devel/attachments/20171014/d58969cb/attachment.html>