On Thu, Jul 04, 2024, Maxim Levitsky wrote: > On Fri, 2024-05-17 at 10:38 -0700, Sean Christopherson wrote: > > Reject KVM_CAP_X86_DISABLE_EXITS if vCPUs have been created, as disabling > > PAUSE/MWAIT/HLT exits after vCPUs have been created is broken and useless, > > e.g. except for PAUSE on SVM, the relevant intercepts aren't updated after > > vCPU creation. vCPUs may also end up with an inconsistent configuration > > if exits are disabled between creation of multiple vCPUs. > > Hi, > > I am not sure that PAUSE intercepts are updated either, I wasn't able to find a code > that does this. > > I agree with this change, but note that there was some talk on the mailing > list to allow to selectively disable VM exits (e.g PAUSE, MWAIT, ...) only on > some vCPUs, based on the claim that some vCPUs might run RT tasks, while some > might be housekeeping. I haven't followed those discussions closely. This change is actually pulled from that series[*]. IIRC, v1 of that series didn't close the VM-scoped hole, and the overall code was much more complex as a result. [*] https://lore.kernel.org/all/20230121020738.2973-2-kechenl@xxxxxxxxxx
