On Mon, 2007-03-19 at 15:30 +0100, Christian Ehrhardt wrote: > Hi, > I have one more questions regarding the oprofile extension to work in > xenppc guests. > > The plain linux implementation sets !always! the vector for the > performance interrupt 0xf00 to the function > "performance_monitor_exception" in head32.S/head64.S. Depending on > wether linux starts profiling this function is set to a dummy or the > "real" handler of e.g. oprofile. > Now in the virtualized environment each guest set's its own interrupt > handler for 0xf00 (Performance monitor interrupt). Because we are > running with LPSE[1]=0 as Jimi wrote before the performance interrupt > while a Dom is running should be handled from the domain because nothing > sets MSR[HV] to 1.
OK, so performance monitor interrupts go directly to the guest. > My question is now if the address translation & virtualization ensures > that each perf interrupt will be a) served by the right function adress > and b) in the domain. Maybe there is some exclusive part involved and > the different writes of the 0xf00 vector may overwrite each other or > something similar - that's why I want to ask to be sure. > > Example of a system with two DomU guests that enabled the performance > counters. > Running: > Xen > 0xf00 -> undef? I'm not sure what to do about a perfmon interrupt in Xen. Since we're saving/restoring the perfmon register state on domain entry/exit, can we just disable those interrupts while running Xen? > Dom0 > 0xf00 -> default_pmc_irq > DomU1 > 0xf00 -> pmc_irq_handler1 > DomU2 > 0xf00 -> pmc_irq_handler2 I don't understand the question about translation. The domains do not share code. For example, it is not possible for an interrupt in Dom1 to trigger an exception handler in Dom0. -- Hollis Blanchard IBM Linux Technology Center _______________________________________________ Xen-ppc-devel mailing list Xen-ppc-devel@lists.xensource.com http://lists.xensource.com/xen-ppc-devel
