Ingo Molnar wrote: > * Avi Kivity <[EMAIL PROTECTED]> wrote: > > >>> unfortunately 0xc011f7f3 is in native_write_msr(), which isnt very >>> helpful. (i have CONFIG_PARAVIRT enabled in the -rt guest and host >>> kernels) But the MSR values suggest that this is the NMI watchdog >>> thing again, trying to program MSR_ARCH_PERFMON_EVENTSEL0 and >>> MSR_ARCH_PERFMON_PERFCTR0, but this time Linux recovered due to a >>> more robust MSR handling. The guest disabled the NMI watchdog with: >>> >>> Testing NMI watchdog ... CPU#0: NMI appears to be stuck (0->0)! >>> >>> the FC6 installer hang that i saw with earlier MMU-branch snapshots >>> is fixed. >>> >> Good. Handling the counter well would have been very difficult, >> especially if attempting to support cross migration. >> > > as far as the NMI watchdog goes, it's in fact better to keep it disabled > this way - it's not like the guest context could 'lock up' in an > undebuggable way. Any NMI activity in the guest context would be pretty > pointless. I'd suggest simulating a non-working performance counter: > i.e. dont inject a #GPF when doing the wrmsr, and maybe preserve the > values that were written into the MSR register, but otherwise dont try > to implement the functionality by injecting NMIs. Worst-case this could > result in user-space debugging tools seeing non-working > performance-counter functionality. > >
My worry is that when emulating an msr incorrectly, software can fail without any clue as to what went wrong. I'll add the emulation as you suggest bug with a printk() to warn that we're bending the rules. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ kvm-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/kvm-devel
