![[Koi]](http://www.verge.net.au/~horms/pleb_blossom/pics/3-0345.jpg)
Xen 3.4.0 has been released and includes two improvements to PCI pass-through that I was involved in:
Allow any unused PCI slot to be used for PCI pass-through, including hot-plug.
Previously only slots 6 & 7 could be used, limiting users to two pass-through devices per domU. The new limit is around 28, as there are 32 possible slots on a PCI bus, and at typically 4 are used by a domU for emulated devices. Fewer devices will be available for pass-through if extra ioemu devices are attached to the domU.
Allow the user to specify slot used for pass-through of devices attached to domU at boot time. This mirrors the ability to select the slot when a device is hot-plugged.
Unfortunately there have also been a number of bugs in pass-through. Many of these have been fixed. But and as of the release a known problem is that domains can't be started if they have previously had PCI devices hot-plugged. At this time I recommend using xm_pci_list_v3.patch and xm_pci_attach_v2.patch which have been provided by Masaki Kanno in his post [PATCH] Fix xm pci-attach/detach for inactivemanaged as a fix for this problem.
Update: Kanno-san's changes have been combined into a single patch
and applied to xen-unstable as
changset: 19618:780041c4a96d "xend: Fix xm pci commands for inactive
managed domains".
Tue, 19 May 2009 12:03:50 +1000| Permalink