Support TSC Rate MSR and enable TSC scaling for nested virtualization. With it, guest VMs don''t need take #VMEXIT to calculate a translated TSC value when it is running under TSC emulation mode. I measured native performance of the rdtsc instruction in the l2 guest with xen-on-xen and both host and and l1 guest run under TSC emulation mode. TSC scaling just needs MSR emulation and correct tsc offset calculation to be done and thus can be emulated also on older hardware. In this case rdtsc instruction is intercepted and handled by the host directly and safes the cost of a full VMRUN/VMEXIT emulation cycle. Signed-off-by: Christoph Egger <Christoph.Egger@amd.com> -- ---to satisfy European Law for business letters: Advanced Micro Devices GmbH Einsteinring 24, 85689 Dornach b. Muenchen Geschaeftsfuehrer: Alberto Bozzo, Andrew Bowd Sitz: Dornach, Gemeinde Aschheim, Landkreis Muenchen Registergericht Muenchen, HRB Nr. 43632 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel