Re: [Libvir] PATCH: Specify BIOS clock offset for HVM

The attached patch introduces a new XML element for specifying information about the guest (BIOS) clock. For Xen HVM, and QEMU / KVM guests this is used to specifyc whether the guest clock should be in UTC, or localtime. The latter is useful for Windows which likes the BIOS to be localtime, while the former is useful for all other operating systems. The former is of course the default - so no change in existing semantics. The <clock> element currently takes a single attribute 'offset'. This is either 'utc' or 'localtime', but if we port to VMWare, it will also allow an arbitrary numeric offset as well as these special constants. <clock offset='utc'/> Or <clock offset='localtime'/> It may later also be desirable to add a 'sync=[yes|no]' attribute to specify whether the HV tries to keep the clock in sync with the HV while it is running. VMWare has this concept, and so does Xen paravirt - though Xen paravirt sets it via /proc/sys/xen/independant_wallclock inside the guest and AFAICT doesn't (yet) expose it to the guest config in Dom0. Anyway, my patch implements use of utc/localtime offsets for Xen, and QEMU drivers. I've tested to verify that -localtime gets passed to the QEMU process as appropriate.