[libvirt] Xen 4.0 and DPCI key in sexpr
This blog post [1] explains how to apply some OpenSuse patches [2] (especially xen-domctl-ver7.patch) to the libvirt 0.8.1 Debian package in order to get Xen 4.0 support. On IRC jonnyt reported problems with PCI passthrough in such a setup. Debugging and XenD hacking revealed that XenD 4.0 extended the sexpr format for PCI devices from (device (pci (dev (domain 0x0000)(bus 0x02)(slot 0x00)(func 0x0)))) to this, including a new key part (device (pci (dev (domain 0x0000)(bus 0x02)(slot 0x00)(func 0x0)(key <whatever-value-xend-expects-here>)))) The Xen upstream commit [3] that added this doesn't explain much about it. I came up with the attached prove-of-concept patch that just hardcodes (key 0x0) for XenD 4.0. On IRC jonnyt confirmed that this patch fixes the immediate error for him: error : xend_post:434 : POST operation failed: xend_post: error from xen daemon: (xend.err "Error creating domain: 'key'") Matthias [1] http://spblinux.de/blog/2010/05/xen-4-0-with-libvirt-0-8-1-replace-xm-new-by... [2] https://build.opensuse.org/stage/package/files?package=libvirt&project=Virtualization [3] http://lists.xensource.com/archives/html/xen-changelog/2009-06/msg00298.html
Matthias Bolte wrote:
This blog post [1] explains how to apply some OpenSuse patches [2] (especially xen-domctl-ver7.patch)
Ah yes, reminds me to upstream this patch. We had all of the cpu pools patches (which changed domctl interface) in Xen4.0 in openSUSE build service. These patches were not included in official Xen4.0 release but have since been included in xen-unstable. In order to use the Xen in OBS, I needed to patch libvirt to handle domctl version 7. Now that the cpu pools patches have been taken in xen-unstable it's time to upstream the libvirt patch as well.
to the libvirt 0.8.1 Debian package in order to get Xen 4.0 support.
Xen4.0 doesn't contain the cpu pools feature, which changes the domctl interface. I guess they are using xen-unstable, or perhaps have Fujitsu's cpu pools patches as well? Thanks, Jim
2010/6/4 Jim Fehlig <jfehlig@novell.com>:
Matthias Bolte wrote:
This blog post [1] explains how to apply some OpenSuse patches [2] (especially xen-domctl-ver7.patch)
Ah yes, reminds me to upstream this patch. We had all of the cpu pools patches (which changed domctl interface) in Xen4.0 in openSUSE build service. These patches were not included in official Xen4.0 release but have since been included in xen-unstable. In order to use the Xen in OBS, I needed to patch libvirt to handle domctl version 7. Now that the cpu pools patches have been taken in xen-unstable it's time to upstream the libvirt patch as well.
to the libvirt 0.8.1 Debian package in order to get Xen 4.0 support.
Xen4.0 doesn't contain the cpu pools feature, which changes the domctl interface. I guess they are using xen-unstable, or perhaps have Fujitsu's cpu pools patches as well?
Thanks, Jim
As I understood his problem Xen 4.0 basically works with a libvirt 0.8.1 version patched as described in the blog post. The actual problem is PCI passthrough, because Xen 4.0 added new required parameters like the key parameter. With the quick fix of hardcoding key to 0x0, he was able to define the domain, but starting the domain failed with XenD complaining about a missing vdevfn parameter. Looking at the commit history suggest that the vslot parameter was just renamed to vdevfn. But libvirt never used the vslot parameter before, and now it seems to be mandatory. I assisted him in debugging and used the Xen 4.0 tarball [1] as basis to look at the code. I think that's the stable version. Therefore, I think this PCI passthrough problem is not related to "CPU pools". Matthias [1] http://www.xen.org/products/xen_source.html
Matthias Bolte wrote:
I assisted him in debugging and used the Xen 4.0 tarball [1] as basis to look at the code. I think that's the stable version. Therefore, I think this PCI passthrough problem is not related to "CPU pools".
Oh, I wasn't suggesting the problems are related. I was just curious why the xen-domctl-ver7.patch was needed for official Xen4.0 release when it doesn't have the change to domctl interface. Regards, Jim
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Jim Fehlig -
Matthias Bolte