On Thu, Sep 16, 2021 at 09:37:43PM +0000, Sean Christopherson wrote: > On Sat, Aug 28, 2021, Peter Zijlstra wrote: > Argh, sorry, I somehow managed to miss all of your replies. I'll get back to > this series next week. Thanks for the quick response! > > > Lets keep the whole intel_pt crud inside x86... > > In theory, I like the idea of burying intel_pt inside x86 (and even in > Intel+VMX code for the most part), but the actual implementation is a > bit gross. Because of the whole "KVM can be a module" thing, ARGH!! we should really fix that. I've heard other archs have made much better choices here. > either > the static call and __static_call_return0 would need to be exported, > or a new register/unregister pair would have to be exported. So I don't mind exporting __static_call_return0, but exporting a raw static_call is much like exporting a function pointer :/ > The unregister path would also need its own synchronize_rcu(). In general, I > don't love duplicating the logic, but it's not the end of the world. > > Either way works for me. Paolo or Peter, do either of you have a preference? Can we de-feature kvm as a module and only have this PT functionality when built-in? :-) > > --- > > Index: linux-2.6/arch/x86/events/core.c > > =================================================================== > > --- linux-2.6.orig/arch/x86/events/core.c > > +++ linux-2.6/arch/x86/events/core.c > > @@ -92,7 +92,7 @@ DEFINE_STATIC_CALL_RET0(x86_pmu_guest_ge > > > > DEFINE_STATIC_CALL_RET0(x86_guest_state, *(perf_guest_cbs->state)); > > DEFINE_STATIC_CALL_RET0(x86_guest_get_ip, *(perf_guest_cbs->get_ip)); > > -DEFINE_STATIC_CALL_RET0(x86_guest_handle_intel_pt_intr, *(perf_guest_cbs->handle_intel_pt_intr)); > > +DEFINE_STATIC_CALL_RET0(x86_guest_handle_intel_pt_intr, unsigned int (*)(void)); > > FWIW, the param needs to be a raw function, not a function pointer. Yeah, I keep making that mistake.. and I wrote the bloody thing :/ I have a 'fix' for that, but I need to finish that and also flag-day change :-( https://lkml.kernel.org/r/YS+0eIeAJsRRArk4@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
