We told you earlier this week about the Linux 3.0 release candidate, but here’s another point of interest: as of the new version, as stated by Wim Coekaert, “every single bit of support needed in Linux to work perfectly well with Xen is -in- the mainline kernel tree.”
Up until now a few patches have been required to the Linux kernal to make Xen hypervisors and virtual machines work. Now those features built right in. Plus, there’s a new kernel mode for dealing with virtualization.
Coekaert explained in more detail in a blog post:
Xen has always used Linux as the management OS (Dom0) on top of the hypervisor itself, to do the device management and control of the virtual machines running on top of Xen. And for many years, next to the hypervisor, there was a substantial linux kernel patch that had to be applied on top of a linux kernel to transform into this “Dom0”. This code had to constantly be kept in sync with the progress Linux itself was making and as such caused a substantial amount of extra work that had to be done.
The Xen team has been working for years to get everything needed to run the Linux kernel as Dom0. Some of the components were added last year, but the final elements have now been added to handle everything.
Another addition that will make the mainline Linux kernel more Xen friendly is pvops, a mode which will enable the kernel to switch between paravirtualization (pv), hardware virtualization (hvm) or paravirtual-hardware virtualization (pv-hvm).
One thing this this means, according to a post by Ewan Mellor
is that Linux distributions will no longer have to package different kernels for Xen support, making it much easier.
