On 28/05/14 10:58, Christoffer Dall wrote: > On Wed, May 28, 2014 at 10:56:45AM +0100, Marc Zyngier wrote: >> On 25/05/14 16:34, Christoffer Dall wrote: >>> On Tue, May 20, 2014 at 05:55:36PM +0100, Marc Zyngier wrote: >>>> This patch series adds debug support, a key feature missing from the >>>> KVM/arm64 port. >>>> >>>> The main idea is to keep track of whether the debug registers are >>>> "dirty" (changed by the guest) or not. In this case, perform the usual >>>> save/restore dance, for one run only. It means we only have a penalty >>>> if a guest is actively using the debug registers. >>>> >>>> The amount of registers is properly frightening, but CPUs actually >>>> only implement a subset of them. Also, there is a number of registers >>>> we don't bother emulating (things having to do with external debug and >>>> OSlock). >>> >>> What is the rationale about not having to deal with external debug and >>> OSlock? >> >> External debug is when you actually plug a physical JTAG into the CPU. >> OSlock is a way to prevent "other software" to play with the debug >> registers. My understanding is that it is only useful in combination >> with the external debug. >> >> In both case, implementing support for this is probably not worth the >> effort, at least for the time being. >> > OK, can we document that somewhere clearly in the code then so we know > how we can simply ignore those registers? Sure. I'll add some documentation. Thanks, M. -- Jazz is not dead. It just smells funny... -- 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
