| Message ID | 20210922000533.713300-9-seanjc@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | perf: KVM: Fix, optimize, and clean up callbacks | expand |
On 22/09/21 02:05, Sean Christopherson wrote: > Introduce GUEST_PERF_EVENTS and require architectures to select it to > allow registering and using guest callbacks in perf. This will hopefully > make it more difficult for new architectures to add useless "support" for > guest callbacks, e.g. via copy+paste. > > Stubbing out the helpers has the happy bonus of avoiding a load of > perf_guest_cbs when GUEST_PERF_EVENTS=n on arm64/x86. > > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > arch/arm64/kvm/Kconfig | 1 + > arch/x86/kvm/Kconfig | 1 + > arch/x86/xen/Kconfig | 1 + > include/linux/perf_event.h | 6 ++++++ > init/Kconfig | 4 ++++ > kernel/events/core.c | 2 ++ > 6 files changed, 15 insertions(+) > > diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig > index a4eba0908bfa..f2121404c7c6 100644 > --- a/arch/arm64/kvm/Kconfig > +++ b/arch/arm64/kvm/Kconfig > @@ -37,6 +37,7 @@ menuconfig KVM > select HAVE_KVM_IRQ_BYPASS > select HAVE_KVM_VCPU_RUN_PID_CHANGE > select SCHED_INFO > + select GUEST_PERF_EVENTS if PERF_EVENTS > help > Support hosting virtualized guest machines. > > diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig > index ac69894eab88..699bf786fbce 100644 > --- a/arch/x86/kvm/Kconfig > +++ b/arch/x86/kvm/Kconfig > @@ -36,6 +36,7 @@ config KVM > select KVM_MMIO > select SCHED_INFO > select PERF_EVENTS > + select GUEST_PERF_EVENTS > select HAVE_KVM_MSI > select HAVE_KVM_CPU_RELAX_INTERCEPT > select HAVE_KVM_NO_POLL > diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig > index afc1da68b06d..d07595a9552d 100644 > --- a/arch/x86/xen/Kconfig > +++ b/arch/x86/xen/Kconfig > @@ -23,6 +23,7 @@ config XEN_PV > select PARAVIRT_XXL > select XEN_HAVE_PVMMU > select XEN_HAVE_VPMU > + select GUEST_PERF_EVENTS > help > Support running as a Xen PV guest. > > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h > index c0a6eaf55fb1..eefa197d5354 100644 > --- a/include/linux/perf_event.h > +++ b/include/linux/perf_event.h > @@ -1238,6 +1238,7 @@ extern void perf_event_bpf_event(struct bpf_prog *prog, > enum perf_bpf_event_type type, > u16 flags); > > +#ifdef CONFIG_GUEST_PERF_EVENTS > extern struct perf_guest_info_callbacks *perf_guest_cbs; > static inline struct perf_guest_info_callbacks *perf_get_guest_cbs(void) > { > @@ -1273,6 +1274,11 @@ static inline unsigned int perf_guest_handle_intel_pt_intr(void) > } > extern void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs); > extern void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs); > +#else > +static inline unsigned int perf_guest_state(void) { return 0; } > +static inline unsigned long perf_guest_get_ip(void) { return 0; } > +static inline unsigned int perf_guest_handle_intel_pt_intr(void) { return 0; } > +#endif /* CONFIG_GUEST_PERF_EVENTS */ Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Having perf_guest_handle_intel_pt_intr in generic code is a bit off. Of course it has to be in the struct, but the wrapper might be placed in arch/x86/include/asm/perf_event.h as well (applies to patch 7 as well). Paolo
On Wed, Sep 22, 2021, Paolo Bonzini wrote: > On 22/09/21 02:05, Sean Christopherson wrote: > > @@ -1273,6 +1274,11 @@ static inline unsigned int perf_guest_handle_intel_pt_intr(void) > > } > > extern void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs); > > extern void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs); > > +#else > > +static inline unsigned int perf_guest_state(void) { return 0; } > > +static inline unsigned long perf_guest_get_ip(void) { return 0; } > > +static inline unsigned int perf_guest_handle_intel_pt_intr(void) { return 0; } > > +#endif /* CONFIG_GUEST_PERF_EVENTS */ > > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> > > Having perf_guest_handle_intel_pt_intr in generic code is a bit off. Of > course it has to be in the struct, but the wrapper might be placed in > arch/x86/include/asm/perf_event.h as well (applies to patch 7 as well). Yeah, I went with this option purely to keep everything bundled together. I have no strong opinion.
On Wed, Sep 22, 2021, Sean Christopherson wrote: > On Wed, Sep 22, 2021, Paolo Bonzini wrote: > > On 22/09/21 02:05, Sean Christopherson wrote: > > > @@ -1273,6 +1274,11 @@ static inline unsigned int perf_guest_handle_intel_pt_intr(void) > > > } > > > extern void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs); > > > extern void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs); > > > +#else > > > +static inline unsigned int perf_guest_state(void) { return 0; } > > > +static inline unsigned long perf_guest_get_ip(void) { return 0; } > > > +static inline unsigned int perf_guest_handle_intel_pt_intr(void) { return 0; } > > > +#endif /* CONFIG_GUEST_PERF_EVENTS */ > > > > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> > > > > Having perf_guest_handle_intel_pt_intr in generic code is a bit off. Of > > course it has to be in the struct, but the wrapper might be placed in > > arch/x86/include/asm/perf_event.h as well (applies to patch 7 as well). > > Yeah, I went with this option purely to keep everything bundled together. I have > no strong opinion. Scratch, that, I do have an opinion. perf_guest_handle_intel_pt_intr() is in common code because the callbacks themselves and perf_get_guest_cbs() are defined in linux/perf_event.h, _after_ asm/perf_event.h is included. arch/x86/include/asm/perf_event.h is quite bereft of includes, so there's no obvious landing spot for those two things, and adding a new header seems like overkill.
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index a4eba0908bfa..f2121404c7c6 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -37,6 +37,7 @@ menuconfig KVM select HAVE_KVM_IRQ_BYPASS select HAVE_KVM_VCPU_RUN_PID_CHANGE select SCHED_INFO + select GUEST_PERF_EVENTS if PERF_EVENTS help Support hosting virtualized guest machines. diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index ac69894eab88..699bf786fbce 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -36,6 +36,7 @@ config KVM select KVM_MMIO select SCHED_INFO select PERF_EVENTS + select GUEST_PERF_EVENTS select HAVE_KVM_MSI select HAVE_KVM_CPU_RELAX_INTERCEPT select HAVE_KVM_NO_POLL diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig index afc1da68b06d..d07595a9552d 100644 --- a/arch/x86/xen/Kconfig +++ b/arch/x86/xen/Kconfig @@ -23,6 +23,7 @@ config XEN_PV select PARAVIRT_XXL select XEN_HAVE_PVMMU select XEN_HAVE_VPMU + select GUEST_PERF_EVENTS help Support running as a Xen PV guest. diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index c0a6eaf55fb1..eefa197d5354 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1238,6 +1238,7 @@ extern void perf_event_bpf_event(struct bpf_prog *prog, enum perf_bpf_event_type type, u16 flags); +#ifdef CONFIG_GUEST_PERF_EVENTS extern struct perf_guest_info_callbacks *perf_guest_cbs; static inline struct perf_guest_info_callbacks *perf_get_guest_cbs(void) { @@ -1273,6 +1274,11 @@ static inline unsigned int perf_guest_handle_intel_pt_intr(void) } extern void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs); extern void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs); +#else +static inline unsigned int perf_guest_state(void) { return 0; } +static inline unsigned long perf_guest_get_ip(void) { return 0; } +static inline unsigned int perf_guest_handle_intel_pt_intr(void) { return 0; } +#endif /* CONFIG_GUEST_PERF_EVENTS */ extern void perf_event_exec(void); extern void perf_event_comm(struct task_struct *tsk, bool exec); diff --git a/init/Kconfig b/init/Kconfig index 55f9f7738ebb..acc7e8ba4563 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1776,6 +1776,10 @@ config HAVE_PERF_EVENTS help See tools/perf/design.txt for details. +config GUEST_PERF_EVENTS + bool + depends on HAVE_PERF_EVENTS + config PERF_USE_VMALLOC bool help diff --git a/kernel/events/core.c b/kernel/events/core.c index 2e3dc9fbd5d9..c6ec05809f54 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6482,6 +6482,7 @@ static void perf_pending_event(struct irq_work *entry) perf_swevent_put_recursion_context(rctx); } +#ifdef CONFIG_GUEST_PERF_EVENTS struct perf_guest_info_callbacks *perf_guest_cbs; void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) @@ -6502,6 +6503,7 @@ void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) synchronize_rcu(); } EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); +#endif static void perf_output_sample_regs(struct perf_output_handle *handle,
Introduce GUEST_PERF_EVENTS and require architectures to select it to allow registering and using guest callbacks in perf. This will hopefully make it more difficult for new architectures to add useless "support" for guest callbacks, e.g. via copy+paste. Stubbing out the helpers has the happy bonus of avoiding a load of perf_guest_cbs when GUEST_PERF_EVENTS=n on arm64/x86. Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/arm64/kvm/Kconfig | 1 + arch/x86/kvm/Kconfig | 1 + arch/x86/xen/Kconfig | 1 + include/linux/perf_event.h | 6 ++++++ init/Kconfig | 4 ++++ kernel/events/core.c | 2 ++ 6 files changed, 15 insertions(+)