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Building qemu-dm for HVM VT-d PCI Pass-Through

If you are building the qemu-dm, device models for xen, from http://xenbits.xensource.com/git-http/qemu-xen-unstable.git or the tools/ioemu-dir/ directory that is created when building http://xenbits.xensource.com/xen-unstable.hg (due to the wonders of the xen build system, they are the same thing). And you are doing this on Debian. And you would like PCI pass-through to work for HVM domains. Then make sure you have the libpci-dev package installed before building. Otherwise qemu-dm will be built without pass-through support. If you install libpci-dev after building then run make clean before rebuilding, to ensure that all files are rebuilt correctly - they won't be otherwise.

If you do this then the instructions in the Xen VT-d How-To should work.

Otherwise you will end up the following nasty message, which just cost me more time than I care to admit, in /var/log/xen/xend.log

ERROR (XendDomainInfo:581) Device model didn't tell the vslots for PCI device

On a semi-related note, if you wish to use VT-d PCI pass-through in paravirtualised domains then pass iommu=pv as an argument to xen when booting. Otherwise non-VT-d pass-through will be used for paravirtualised domains. This is independent whether qemu-dm was compiled with libpci-dev present or not.

Fri, 12 Dec 2008 16:58:52 +1100| Permalink