On Wed, Nov 29, 2017 at 11:26:30PM +0100, Paolo Bonzini wrote: > On 29/11/2017 19:20, Andi Kleen wrote: > > But I haven't looked too closely, but I suspect you'll clobber global > > kernel debugger state this way. > > I checked all callers of update_debugctlmsr, and couldn't find any that > could run asynchronously while KVM is caching the value. For example > __switch_to_xtra would always run before the sched_in notifier. True. It would only be a problem if the debugger supported branch stepping or LBRs, which it doesn't seem to currently. -Andi
