Xen users - May 2007 - Same IRQ in dom0 and domU by different hardware causes dom0 crash

Hi, this is my first mail in this list. I''ve installed Xen in Debian
Etch and
created a virtual domU Debian Etch as well.

In domU I''ve installed an Asterisk and want to use a Beronet ISDN card:

  ~# lspci
  0a:01.0 ISDN controller: GmbH ISDN network Controller [HFC-4S] (rev 01)

So I pass the iSDN card PCI to domU by adding in dom0
"/boot/grub/menu.lst":
---
module /boot/vmlinuz-2.6.18-4-xen-686 root=/dev/sda1 ro pciback.hide=(0a:01.0)
---

After that, I see the PCI in domU:

  ~# lspci
  00:00.0 ISDN controller: GmbH ISDN network Controller [HFC-4S] (rev 01)


-- PROBLEM --
My first problem is that dom0 and domU share IRQ 18:

** dom0 **
  ~# cat /proc/interrupts
              CPU0           CPU1
   18:      14140          0        Phys-irq  uhci_hcd:usb3

** domU **
  ~# cat /proc/interrupts
              CPU0
   18:      16507        Phys-irq  HFC-multi

Obviously, the interrupts so big number by IRQ18 in dom0 is "false",
they are
in fact interruptions of the HFC card in domU.

If I reboot or destroy domU I get a dom0 message:
  Disabling IRQ #18

and dom0 looses net, keyboard and so. I must restart it.


-- WORKAROUND --
I can quit the module "uhci_hcd" in dom0 which is using IRQ 18 and the
problem
dissapears, but of course it''s not a good/clean solution.

But I have another problem with this workaround: I''d like to quit this
module
for the start by adding to "/etc/modprobe.d/blacklist":
  blacklist  uhci_hcd

but it doesnt'' work and the module is loaded anyway. I can''t
understand
because I use that method to avoid loading other modules in the same Debian 
Etch and it works. Any idea about this problem?


-- SOLUTION --
I''d like a way to dissable IRQ 18 in dom0. Anyway I think that the only
solution is by editing the Bios and dissabling or chanching that IRQ
(haven''t
tryied it yet) but I''d like to listen to other suggestions.


-- POSSIBLE BUG? --
Waht I really care is this IRQ sharing between dom0 and domU by different 
hardware. Is it really normal?
I''ve found other case exactly the same as mine without no response:
  http://lists.xensource.com/archives/html/xen-users/2006-05/msg00967.html



Thanks for any help.

Regards.


--
*Iñaki Baz Castillo*
ibc@in.ilimit.es

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On 08-05-2007, Iñaki Baz Castillo <ibc@in.ilimit.es>
wrote:
> Hi, this is my first mail in this list. I''ve installed Xen in
Debian Etch and
> created a virtual domU Debian Etch as well.
>
> In domU I''ve installed an Asterisk and want to use a Beronet ISDN
card:
>
>   ~# lspci
>   0a:01.0 ISDN controller: GmbH ISDN network Controller [HFC-4S] (rev 01)
>
> So I pass the iSDN card PCI to domU by adding in dom0
"/boot/grub/menu.lst":
> ---
> module /boot/vmlinuz-2.6.18-4-xen-686 root=/dev/sda1 ro
pciback.hide=(0a:01.0)
> ---
>
> After that, I see the PCI in domU:
>
>   ~# lspci
>   00:00.0 ISDN controller: GmbH ISDN network Controller [HFC-4S] (rev 01)
>
>
> -- PROBLEM --
> My first problem is that dom0 and domU share IRQ 18:
>
> ** dom0 **
>   ~# cat /proc/interrupts
>               CPU0           CPU1
>    18:      14140          0        Phys-irq  uhci_hcd:usb3
>
> ** domU **
>   ~# cat /proc/interrupts
>               CPU0
>    18:      16507        Phys-irq  HFC-multi
>
> Obviously, the interrupts so big number by IRQ18 in dom0 is
"false", they are
> in fact interruptions of the HFC card in domU.
>
> If I reboot or destroy domU I get a dom0 message:
>   Disabling IRQ #18
>
> and dom0 looses net, keyboard and so. I must restart it.
>
>
> -- WORKAROUND --
> I can quit the module "uhci_hcd" in dom0 which is using IRQ 18
and the problem
> dissapears, but of course it''s not a good/clean solution.
>
> But I have another problem with this workaround: I''d like to quit
this module
> for the start by adding to "/etc/modprobe.d/blacklist":
>   blacklist  uhci_hcd
>
> but it doesnt'' work and the module is loaded anyway. I
can''t understand
> because I use that method to avoid loading other modules in the same Debian
> Etch and it works. Any idea about this problem?
>
>
> -- SOLUTION --
> I''d like a way to dissable IRQ 18 in dom0. Anyway I think that the
only
> solution is by editing the Bios and dissabling or chanching that IRQ
(haven''t
> tryied it yet) but I''d like to listen to other suggestions.
>
>
> -- POSSIBLE BUG? --
> Waht I really care is this IRQ sharing between dom0 and domU by different 
> hardware. Is it really normal?
> I''ve found other case exactly the same as mine without no
response:
>   http://lists.xensource.com/archives/html/xen-users/2006-05/msg00967.html
>
>
I have exactly the same kind of problems:
* hide audio card from dom0
* unhide audio card in domU
* audio card share IRQ with eth0, hda
* after a long time (more than 24 hours running), i loose audio card,
  eth0 and hda. 
* the mouse become unresponsive (not frozen, only very slow)
* eth0 is dead 
* hda: lost interrupt ide-cd: cmd 0x3 timedout hda: request sense
  failure...

I have upgraded my BIOS et al. I cannot find a good solution to this
problem...

For now, i am trying to run vanilla linux (without xen). If it perform a
week of uptime, i will consider the audio/eth0 problem as a Xen related
problem (the host is actually running fine since 40 hours which is 12
hour better than with Xen)

Regards,
Sylvain Le Gall


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