Re: DMA trouble with current xen-sparse

[Daniel Veillard <veillard@redhat.com>]

On Wed, Nov 02, 2005 at 05:12:27PM +0000, Keir Fraser wrote:
> 
> On 2 Nov 2005, at 15:59, Daniel Veillard wrote:
> 
> >[root@localhost ~]# ethtool -K eth0 tso off
> >Cannot set device tcp segmentation offload settings: Operation not 
> >supported
> >
> >  too bad ...
> >  with 'swiotlb=force swiotlb=8m' kernel parameters the box is stable,
> >without it very basic network access can crash it (say 'locate lib' 
> >over ssh)
> >and then the whole system reboots.
> >
> >  100% reproductible for me, and without crazy hardware :-)
> 
> It'd be interesting to know what form of skbuffs get sent to the driver 
> when this happens. e.g., how big is the skbuff data area, is the skbuff 
> fragmented, etc.

  I'm not a kernel hacker, but if you give me a patch displaying those
informations at the IOMMU_BUG_ON pointed by Steven, I will gladly rebuild 
and try to reboot over it to give you the informations (I have no serial
so hint on avoiding the instant reboot of the dom0 would help). Oh yeah
it's just dom0 on top of the hypervisor, no domU even started.

Daniel

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