Re: PCI passthrough issue

[Ian Campbell <Ian.Campbell@citrix.com>]

On Fri, 2011-02-04 at 13:15 +0000, Jean Baptiste Favre wrote:

> 
> >> What is a bit strange here is that I don't any more the KERN_CRIT printk
> >> message.
> >> Could be a false positive ?
> > 
> > Worth bearing in mind, lets see what the next test run produces.
> Seems that I got this messge only with copybreak=0.
> With default value (128), no such message
> 
> More, with copybreak=0, all packets are dropped (even a ping with
> default packet size is dropped. Same with ping -s1)

Hang on, I thought you previously said copybreak=0 made everything work
ok. If that isn't definitely the case then we may be following a red
herring.

Are you saying that copybreak=0 + this patch breaks? That would be very
surprising since the patch doesn't cause any flow control differences.

Perhaps there is some difference between your self-built kernels and the
Debian kernels you started with? Perhaps you should try the self built
kernel with no patches, just to confirm it behaves the same as the
Debian kernels?

> > Thanks.
> > 
> > Please gather the tcpdump's too.
> Both tcpdump from GW and domU are Attached.

Were these collected with or without patches? With or without ethtool -K
options? With or without copybreak?

Please try and be explicit about everything you post, there are lots of
variables in the air.

> Commands were:
> 
> domU# tcpdump -n -w domU.cap -s0 -i eth0 ether host 00:1f:c6:eb:71:43 or
> ether broadcast
> 
> gw# tcpdump -n -w gw.cap -s0 -i br0 ether host 00:1f:c6:eb:71:43 or
> ether broadcast

So no 0x20 anywhere in what the gw sent as the reply and still no clue
where the value came from...

Ian.