Re: [PATCH v2 00/13] perf: KVM: Fix, optimize, and clean up callbacks
From: Sean Christopherson <seanjc@google.com>
Date: 2021-09-16 21:38:14
Also in:
kvm, kvmarm, linux-arm-kernel, linux-riscv, lkml, xen-devel
On Sat, Aug 28, 2021, Peter Zijlstra wrote:
On Fri, Aug 27, 2021 at 05:35:45PM -0700, Sean Christopherson wrote:quoted
Like Xu (2): perf/core: Rework guest callbacks to prepare for static_call support perf/core: Use static_call to optimize perf_guest_info_callbacks Sean Christopherson (11): perf: Ensure perf_guest_cbs aren't reloaded between !NULL check and deref KVM: x86: Register perf callbacks after calling vendor's hardware_setup() KVM: x86: Register Processor Trace interrupt hook iff PT enabled in guest perf: Stop pretending that perf can handle multiple guest callbacks perf: Force architectures to opt-in to guest callbacks KVM: x86: Drop current_vcpu for kvm_running_vcpu + kvm_arch_vcpu variable KVM: x86: More precisely identify NMI from guest when handling PMI KVM: Move x86's perf guest info callbacks to generic KVM KVM: x86: Move Intel Processor Trace interrupt handler to vmx.c KVM: arm64: Convert to the generic perf callbacks KVM: arm64: Drop perf.c and fold its tiny bits of code into arm.c / pmu.c
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, either the static call and __static_call_return0 would need to be exported, or a new register/unregister pair would have to be exported. 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?
quoted hunk ↗ jump to hunk
--- 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.