On Thursday, September 22, 2022 9:35 PM, Peter Zijlstra > On Thu, Sep 22, 2022 at 12:58:49PM +0000, Wang, Wei W wrote: > > > Add a function to expose the current running PT event to users. One > > usage is in KVM, it needs to get and disable the running host PT event > > before VMEnter to the guest and resumes the event after VMexit to host. > > You cannot just kill a host event like that. If there is a host event, the guest > looses out. OK. The intention was to pause the event (that only profiles host info) when switching to guest, and resume when switching back to host. I don't think it is proper to directly disable it via clear MSR_IA32_RTIT_CTL, e.g. there may be dangling PT bit in the interrupt status register, this invokes the PT interrupt handler to re-enable it (for more details about the issue please see patch 3 commit). Would you have any suggestions to pause it? Thanks, Wei
