Chris Lalancette wrote: > Avi Kivity wrote: > >> Excellent catch, but the fix is wrong. Instead of partially restoring >> the ioapic state in the kernel, you should fully save it in qemu. >> >> This is a trap that many fall into: considering kvm and qemu as one >> entity and making sure they work well together. We need to make sure >> that kvm and libkvm are useful for other userspace programs as well. >> >> > > Actually, let me ask a question here. It seems to me that there are two > ways I could go about this: > > 1) Change the save protocol so that it saves the relevant information > (i.e. base_address and irr), and then the restore protocol so it > actually pulls this stuff off the wire. This solution seems more > "right" to me, but it has the downside that we are changing the > over-the-wire information, which will break migration between old and > new versions of qemu. > >
qemu supports backwards compatible changes to the protocol via the version field. > 2) Just change the restore protocol so that we properly fill in the > missing fields with real, hard-coded values instead of just random > memory. This has the benefit that it doesn't change the protocol, but > has the downside that we won't reflect changes to base_address or irr > 100% properly. In practice, this doesn't seem like a big deal since > there doesn't currently seem to be a way to change base_address anyway, > and losing the irr doesn't seem to be catastrophic (although I'm not > 100% certain about that). > > The attached patch implements 2); does anyone have an opinion on which > way to go here? > I prefer doing a full save/restore, since we don't know what guests depend on. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
