Hi, I''m a student working on a research project using xen, and part of what we are doing requires the ability to use the branch tracing facilities of the processor. I.e. we need to be able to write to the IA32_DEBUGCTL MSR and read from the Last Branch Record (LBR) stack (the second of which it appears we can do). We saw a thread discussing this: http://lists.xensource.com/archives/html/xen-devel/2007-08/msg00198.html . However, it doesn''t appear that the method was ever finalized, and we were unable to find a patch. Does such a patch exist, or is there simple way we can read and write to the necessary MSRs in our VM? Can we just hack the xen code to set the correct bits in the VMCS MSR bitmaps? If so, where are those bitmaps set in the code? Thanks a lot. Ryan (Sorry if this hit the list twice. The one I sent yesterday didn''t appear to go through.) _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users