Tom Horsley wrote: > On Fri, 15 Jan 2010 18:37:57 +0100 > Jan Kiszka wrote: > >> Tom Horsley wrote: >>> I just submitted this fedora bug with lots of details: >>> >>> https://bugzilla.redhat.com/show_bug.cgi?id=555788 >>> >>> It sure seems to me like the contents of the debug >>> address trap registers are leaking across virtual machines >>> (at least for opterons on this motherboard :-). >> Are only AMD boxes affected, or did you also test on Intel? > > I haven't explicitly tested on Intel, but we did just see a > compile on a guest on the Intel host also get the same > Breakpoint/Trap error out of the blue, so it looks as if it > does happen on intel as well as amd. OK, will have a look at your test application once time permits. > > I'm going to try on my home system (intel) some more this > evening when I get home. > > Some of the symptoms sort of lead me to think it might be > inheriting random leftover DRn registers at the time a > new virtual machine is created since a VM that has problems > seems to keep having problems, and other VMs zip along > with no problems at all. We have a lazy scheme for switching DR content, but we always clear any triggering bit in DR7 before returning to Linux (which includes other VMs). > >>> Anyone seen anything like this before? (I've been >>> having similar problems on this host since it was >>> running xen 3.1 before switching to kvm). >> I still have one debug register oddity on my todo list (that one causes >> an unhandled VM exit), but I'm not aware of such an issue nor do I >> remember any patch between 2.6.31.x and now at the moment that may have >> fixed it. Nevertheless, could you retry with latest kvm kernel or a >> recent kvm-kmod release? > > Not sure how to do that - if it isn't in the fedora repos, I'm in > uncharted territory trying to run special kernels :-). kvm-kmod should only be about ./configure && make. You do not even need to install it (if you want to keep your host "clean"), just 'rmmod kvm-amd kvm' and insmod the kvm.ko and kvm-amd.ko that is in kvm-kmod/x86 after the build. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
