On Tue, Apr 21, 2015 at 1:51 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Tue, Apr 21, 2015 at 06:32:54PM +0200, Paolo Bonzini wrote: > >> However, if you take into account that RDPMC can also be used >> to read an inactive counter, and that multiple guests "fight" for the >> same host counters, it's even harder to ensure that the guest counter >> indices match those on the host. > > That doesn't make sense, only a single vcpu task will ever run at any > one time. > > There cannot be inter guest counter contention. Only the host can > compete for the same resources. One question is whether we care if we leak unrelated counters to the guest. (We already leak them to unrelated user tasks, so this is hopefully not a big deal. OTOH, the API is different for guests.) Another question is whether it's even worth trying to optimize this. --Andy -- 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
