Re: [Xen-devel] dom0 / hypervisor hang on dom0 boot

["Dugger, Donald D" <donald.d.dugger@xxxxxxxxx>]

Jan-

We have people looking into graphics virtualization, let me ask and see if 
anyone can help out.

--
Don Dugger
"Censeo Toto nos in Kansa esse decisse." - D. Gale
Ph: 303/443-3786


-----Original Message-----
From: Jan Beulich [mailto:JBeulich@xxxxxxxx] 
Sent: Thursday, May 16, 2013 6:10 AM
To: Dugger, Donald D; Dietmar Hahn
Cc: Andrew Cooper; xen-devel@xxxxxxxxxxxxx; Konrad Rzeszutek Wilk
Subject: Re: [Xen-devel] dom0 / hypervisor hang on dom0 boot

>>> On 16.05.13 at 13:07, Dietmar Hahn <dietmar.hahn@xxxxxxxxxxxxxx> wrote:
> The function behind the pointer intel_private.driver->write_entry is
> i965_write_entry(). And the interesting instruction seems to be:
>   writel(addr | pte_flags, intel_private.gtt + entry);
> 
> I added another printk() on start of the function i965_write_entry().
> And surprisingly  after printing a lot of messages the kernel came up!!!
> But now I had other problems like losing the audio device (maybe timeouts).
> So maybe the hang is a timing problem?

Apparently. As the caller is running this in a loop, did you check
whether it's the first or always the same entry that it hangs on?

> What I wanted to check is, what the hypervisor is doing while the system 
> hangs.

Probably nothing in this case, as it doesn't get involved in the MMIO
write being carried out.

> Has anybody an idea maybe a timer and after 30s printing a dump of the stack 
> of all cpus?

That would be the watchdog, which you said doesn't kick in either.

I'm afraid this is a problem with the graphics device's processing of
the written data (locking up the machine at the bus level). Without
help from someone knowing what the driver is supposed to do here,
and what therefore might be going wrong, I don't see good chances
of making progress here. Don - any idea who that could be?

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel