DL385 G2 - PCI-DMA: Random memory would be DMAed

[Zachary Richmond <admin.ihsdoor@gmail.com>]

Mark suggested that I post this to the xen-devel list (I had orginally posted 
to xen-users):

Original post:

 > I am attempting to run Xen 3.1.1 on a HP DL385 G2 box (opteron based
 > system), using Gentoo.  The machine will boot, and I can login and edit
 > files etc, but as soon as I do anything more intensive such as copying
 > files off a cdrom (making me think it is a cciss driver problem) or running
 > make, I get the following :
 >
 >     kernel panic not syncing: PCI-DMA: Random memory would be DMAed
 >
 > Searching on this doesn't come up with much except the source code where
 > this error message is written out.  The comment there indicates there is an
 > IOMMU problem, but I am not sure where to go from there. I am pretty sure
 > it is not a hardware issue since, when booting with a non-xen kernel and
 > the same file system, no problem.  Anyone have any ideas or run into this
 > problem before?
 >
 > As a side note, I have two of these boxes which are identical, and I have
 > successfully installed XenExpress on one of them, in the hopes of finding
 > something there.


To answer Mark's question:

 > What kernel are you using?

from gentoo: xen-sources-2.6.20-r6

Regarding the full error message, all I am getting is:

     kernel panic not syncing: PCI-DMA: Random memory would be DMAed

since the machine is rebooting after that.  There maybe somewhere else to get 
more detail, but beyond dmesg or messages I am not sure where else to look.



     Zak