[dts] Userspace testing

[dts] Userspace testing

[Owen Hilyard]

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Hello all,

I was wondering what everyone's thoughts on doing both userspace testing
and unprivileged testing of dpdk applications is. DTS currently runs all
commands on the tester and the dut as the root user. Please correct me if
I'm wrong, but I was under the assumption that most applications written
with dpdk would not run as root. This could present a problem since it is
possible that permissions errors could arise and we wouldn't notice it due
to the way we currently test. Given that, I was wondering what should and
should not be possible as a normal (non-root) user, and what would be the
best way to go about verifying this.

Thanks

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Re: [dts] [dpdk-dev] Userspace testing

[Owen Hilyard]

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Thanks for the advice.

I was wondering about the state of the "Setup VFIO permissions" option in
the setup script. It seems to just modify the character device's
permissions and then check their memory limit. Should this option also
handle the hugepages setup?

Thanks

On Wed, Jul 29, 2020 at 11:35 AM Burakov, Anatoly <anatoly.burakov@intel.com>
wrote:

> On 29-Jul-20 3:34 PM, Owen Hilyard wrote:
> > Hello all,
> >
> > I was wondering what everyone's thoughts on doing both userspace testing
> > and unprivileged testing of dpdk applications is. DTS currently runs all
> > commands on the tester and the dut as the root user. Please correct me if
> > I'm wrong, but I was under the assumption that most applications written
> > with dpdk would not run as root. This could present a problem since it is
> > possible that permissions errors could arise and we wouldn't notice it
> due
> > to the way we currently test. Given that, I was wondering what should and
> > should not be possible as a normal (non-root) user, and what would be the
> > best way to go about verifying this.
> >
> > Thanks
> >
>
> This is useful, but not everything is supposed to work with limited
> privileges. Things that definitely *won't* work are KNI and anything
> igb_uio-related. Everything VFIO should work fine, and setting up
> correct permissions for hugepages and VFIO is one of the trickier things
> that even I don't know how to do correctly off the top of my head :D
>
> An easy stopgap way of running almost everything as an unprivileged user
> is to use in-memory mode (--in-memory EAL switch); this will cause EAL
> to reserve hugepages etc. without touching the filesystem, sacrificing
> secondary process support in the process (so e.g. EAL autotest won't
> work in --in-memory mode as it relies on secondary process support).
>
> So, i would say that it would be a valuable thing to test for, but be
> aware that not everything is expected to work.
>
> --
> Thanks,
> Anatoly
>

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Re: [dts] [dpdk-dev] Userspace testing

[Owen Hilyard]

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On Fri, Jul 31, 2020 at 5:12 AM Burakov, Anatoly <anatoly.burakov@intel.com>
wrote:

> On 30-Jul-20 5:54 PM, Owen Hilyard wrote:
> > Thanks for the advice.
> >
> > I was wondering about the state of the "Setup VFIO permissions" option
> > in the setup script. It seems to just modify the character device's
> > permissions and then check their memory limit. Should this option also
> > handle the hugepages setup?
>
> I was under the (mis?)impression that the hugepage setup part of the
> script did that?
>
>
It doesn't appear to set them up so that non-root users can use them. From
what I can tell it only creates the pages, but doesn't change permissions
on them in any way.

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Re: [dts] [dpdk-dev] Userspace testing

[David Marchand]

On Wed, Jul 29, 2020 at 4:35 PM Owen Hilyard <ohilyard@iol.unh.edu> wrote:
> I was wondering what everyone's thoughts on doing both userspace testing
> and unprivileged testing of dpdk applications is. DTS currently runs all
> commands on the tester and the dut as the root user. Please correct me if
> I'm wrong, but I was under the assumption that most applications written
> with dpdk would not run as root. This could present a problem since it is
> possible that permissions errors could arise and we wouldn't notice it due
> to the way we currently test. Given that, I was wondering what should and
> should not be possible as a normal (non-root) user, and what would be the
> best way to go about verifying this.

That is an interesting idea.

There are things that won't work unless you give proper permissions
(vfio, hugepages) or capabilities (like for bifurcated solutions: mlx
being the first example that comes to mind).
Additionally, some distributions apply further restrictions, like
SElinux in RHEL. But on this side, I don't think it makes sense, as
selinux rules are distrib specific.

-- 
David Marchand