On 31.01.2013, at 19:54, Scott Wood wrote: > On 01/31/2013 12:52:41 PM, Alexander Graf wrote: >> On 31.01.2013, at 19:43, Scott Wood wrote: >> > On 01/31/2013 12:21:07 PM, Alexander Graf wrote: >> >> How about something like this? Then both targets at least suck as much :). >> > >> > I'm not sure that should be the goal... >> > >> >> Thanks to e500mc's awful hardware design, we don't know who sets the >> >> MSR_DE bit. Once we forced it onto the guest, we have no change to know >> >> whether the guest also set it or not. We could only guess. >> > >> > MSRP[DEP] can prevent the guest from modifying MSR[DE] -- but we still >> > need to set it in the first place. >> > >> > According to ISA V2.06B, the hypervisor should set DBCR0[EDM] to let the >> > guest know that the debug resources are not available, and that "the value >> > of MSR[DE] is not specified and not modifiable". >> So what would the guest do then to tell the hypervisor that it actually >> wants to know about debug events? > > The guest is out of luck, just as if a JTAG were in use.
Hrm. Can we somehow generalize this "out of luck" behavior? Every time we would set or clear an MSR bit in shadow_msr on e500v2, we would instead set or clear it in the real MSR. That way only e500mc is out of luck, but the code would still be shared. Alex -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
