Re: [Xen-devel] Xen >4.10 bricks onboard NIC of Dell Optiplex 7060

[Jan Beulich <jbeulich@xxxxxxxx>]

On 30.10.2019 19:24, Bell, Oren wrote:
> Running Xen Dom0-less leaves the NIC intact, so you're correct in assessing 
> that Xen by itself is not the cause.
> As for running without the driver, I'm not sure that's possible (at least for 
> my competency). It uses the Intel Base Gigabit driver that's built into the 
> kernel.

Well, if there's a kernel side aspect to it (which now seems
pretty likely), then playing with the kernel will be unavoidable.
A first step would be to build a kernel with the driver not built
in, but as a module, such that its loading could be prevented (an
alternative would be a kernel without the driver). Then again I
seem to vaguely recall there being means to suppress the binding
of a driver to particular devices via the kernel command line. I'm
not going to exclude though that this might be distro specific, or
be restricted to even more special cases like distro installation.

> And running the machine without using the NIC will still break it.
> 
> As for the IOMMU suggestion: we still got basic pinging to work, assuming an 
> IP address was statically allocated, so I don't think IOMMU is a valid route 
> for investigation, as any aberrations there should leave the NIC totally 
> non-functional.

I'm confused - basic pinging seems to contradict your unconditional
"bricks" statement. This would rather suggest something during
normal operation breaks things, rather than (as assumed so far) a
specific initialization step. Yet even above you state "And running
the machine without using the NIC will still break it" - this again
suggests some setup step to be at fault. Or perhaps we don't share
an understanding of what "not using the NIC" means: I imply here
that the NIC doesn't get initialized, just its driver loaded (i.e.
no IP address assigned, and hence in particular also no working
pings).

And btw - please don't top-post.

Jan

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