On 11/21/2014 03:45 PM, Andrew Cooper wrote:
On 21/11/14 14:39, Juergen Gross wrote:
Hi,
again a fallout from my "linear p2m list" tests:
Trying to do PCI-passthrough with a 32-bit pv-domain I passed the
wrong device to the domain. The MMIO address was too large for a
MFN of a 32-bit system (it was 380003200000-3800036fffff).
Instead of rejecting the operation Xen tried to perform it resulting
in a (quite understandable) failure in the domU.
I think either the hypervisor or the tools should refuse to do
PCI-passthrough in this case.
What actually goes wrong? Does the 32bit guest truncate the MMIO region
to 44 bits and try to map that?
I think it is 42 bits (the top 2 bits of the MFN are the "identity" and
"foreign" bits).
I would completely agree that something (libxl?) should refuse this
attempt to do passthrough, but I think pci-front should also kick up a
fuss if it is able to detect this error.
Indeed.
Juergen
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
