On Wed, 2015-01-14 at 16:03 +0000, Julien Grall wrote: > Hi Ian, > > On 14/01/15 11:02, Ian Campbell wrote: > > On Tue, 2015-01-13 at 20:07 +0000, Julien Grall wrote: > >> Some platform (such as the VFP Base AEMv8 model) has a memory mapped > >> timer. We don't want DOM0 use this timer rather than the generic ARM > >> timer. So blacklist it for all platforms. > > > > It seems that these registers contain things like the ability to stop > > the counter or change its frequency. So we certainly don't want dom0 > > getting at those! > > > > It's not clear to me if accesses to these registers are trapped > > according to the controls available for the CP registers, or if we would > > have to resort to trapping the entire MMIO page if we wanted to support > > access to these registers (I don't think we would want to anyway). > > I didn't find any spec for the memory mapped timer. But looking to the > driver, it looks like they also have the concept of physical/virtual. So > we may not need to trap. > > Anyway, before implementing anything I'd like to find the corresponding > spec.
It's in the ARM ARM, Appendix E of v7, plus references from Chapter B8. I'd imagine it was in the v8 ARM ARM too, but I've not looked. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel