On Wed, Aug 09, 2006 at 11:54:26PM +0100, Daniel P. Berrange wrote: [ lot of details about problems ]
The upshot of all this is that although the last release of libvirt included HVM support it was basically unusable for domain creation unless you were using HD to boot. The XML returned was also incorrect.
Now the good news. Since it was sooo broken, we can fix without worrying about XML compatability since there is no way any application could be relying on it in its current state.
Agreed. And the changes suggested should not affect the very simple case which worked, except for the 'ioemu:' device prefix. We can just discard it when reading the XML and add it when just discard it except that before xen-3.0.3 this will need to be added back, and post xen-3.0.3 this should be allowed by xend [...]
The other part of the patch is to deal with definition of the floppy and cdrom device backing files. For this I have done the following: [...] The patch has a little bit of logic such that when converting the <devices> block backinto an SEXPR it filters out the disk entries with a dev of 'fda', 'fdb' and 'cdrom' since they need to end up in a different part of the SEXPR. [...] Then the SEXPR sent to XenD will include
(image (hvm (serial pty)))
Which enables allocation of PseudoTTY for the HVM's serial console.
All this sounds good.
I have tested that with this patch I can successfully create a HVM domain which boots off a floppy, harddrive or cdrom. Furthermore if you then dump the XML of this domain,the XML you get back will match the XML you fed in (with the obvious exception of domain ID, and the Pseudo TTY path).
If you have been monitoring xen-devel mailing lists you'll be aware that in 3.0.3 the way CDROM devices are configured is changing:
http://lists.xensource.com/archives/html/xen-devel/2006-08/msg00369.html
Although the patch attached does not support the config outlined in that mail, I'm pretty confident that a small incremental patch will be able to support it without breaking compatability with the changes I've outlined in this mail. The only tricky bit will be that we need to detect whether libvirt is running against a 3.0.2 or 3.0.3 version of XenD to decide how to convert XML -> SEXPR & vica verca.
yeah, and really I don't know how to find it... Daniel -- Red Hat Virtualization group http://redhat.com/virtualization/ Daniel Veillard | virtualization library http://libvirt.org/ veillard@redhat.com | libxml GNOME XML XSLT toolkit http://xmlsoft.org/ http://veillard.com/ | Rpmfind RPM search engine http://rpmfind.net/