On Fri, Sep 09, 2016 at 11:31:07AM +0200, Michal Privoznik wrote: > On 08.09.2016 16:15, Peter Krempa wrote: > > On Thu, Sep 08, 2016 at 14:59:07 +0100, Daniel Berrange wrote: > >> On Thu, Sep 08, 2016 at 03:50:40PM +0200, Michal Privoznik wrote: > > > > [...] > > > >> This is very different to how we deal with addressing for all other > >> types of device in libvirt, where we always assign addresses > >> immediately at time the guest is defined. By only assigning addresses > >> transiently when QEMU starts up, then you're liable to get different > >> addressing even if the DIMM config isn't isn't changed. eg addition > >> of other unrelated devices may alter the address QEMU ends up assigning > >> to the DIMMS. Your arguments in favour of not having persistent addresses > >> aren't really in any way specific to DIMMs, so if we wanted to take that > >> approach, then it would apply to all types of device. So I think we need > >> to fix DIMM address assignment so that it works exactly the same way as > >> we do for all other device addressing needs and assign it up front. > > > > Well, we certainly can assign the slot numbers (I'm going to fix this > > soon as it may create problems). > > > > It's nearly impossible for us to assign the memory module base address > > though. This would require to re-implement all the platform specific > > code that maps memory in qemu which would be ridiculous. > > > > I think that an attempt to do so would most certainly break if not kept > > in sync with qemu. I still strongly prefer not to attempt to do this and > > just discover the addresses so that we can keep them across migrations. > > Agreed. Let's do the slots and leave the mapping address for hypervisor > to assign. Moreover, other hypervisors may implement different > algorithms, so if we were to copy what qemu does - would that work with > other hypervisors? Agreed, doing the slots is sufficient Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list