Re: [Xen-devel] [PV] PCI passthrough and interrupt sharing

["Thomas Friebel" <thomas.friebel@xxxxxxx>]

Hello Chris,

thank you for spending time n this issue.

On Tue, 2007-06-05 at 16:29 -0400, Chris wrote:
> Thomas Friebel wrote:
> > When both NICs share the same IRQ, sooner or later host and
> > guest networking both hang.
> 
> I'm having trouble reproducing this behavior.

What I do is the following:

Fetch 3.1-testing, compile a 64bit kernel with the default config plus
sATA (to access the root fs), plus RTL8169 and nForce NIC support (the
two used NICs).

Start the kernel with acpi=off. Do a 'ifconfig eth2 up' (eth0 is started
by the init scripts) and 'cat /proc/interrupts' shows:

 11:      62182          0        Phys-irq  peth0, eth2

The, after executing

# SLOT=0000:04:08.0
# echo -n $SLOT > /sys/bus/pci/drivers/r8169/unbind
# echo -n $SLOT > /sys/bus/pci/drivers/pciback/new_slot
# echo -n $SLOT > /sys/bus/pci/drivers/pciback/bind

'cat /proc/interrupts' shows:

 11:      74742          0        Phys-irq  peth0

and no line for pciback. Then I start the driver domain and
'cat /proc/interrupts' shows:

 11:      74742          0        Phys-irq  peth0
...
264:        126          0     Dynamic-irq  pciback

The guest then successfully loads the r8169 driver and the network is
working. After some time, even without stressing the driver domain
network, the host hangs.

> After a long wait (it's been running for at least 15 minutes now)
> connectivity in both dom0 and domU are (a bit sluggish but) still
> working normally.

15 minutes are enough time. For me it didn't work longer than 4 minutes
a time.

Maybe it's a problem of one of the two involved NIC drivers?


Kind regards

-- 
Thomas Friebel
Operating System Research Center
AMD Saxony, Dresden, Germany
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