[PATCH V10 01/18] perf/core: Use static_call to optimize perf_guest_info_callbacks
From: Zhu Lingshan <hidden>
Date: 2021-08-06 13:38:36
From: Like Xu <redacted> For "struct perf_guest_info_callbacks", the two fields "is_in_guest" and "is_user_mode" are replaced with a new multiplexed member named "state", and the "get_guest_ip" field will be renamed to "get_ip". For arm64, xen and kvm/x86, the application of DEFINE_STATIC_CALL_RET0 could make all that perf_guest_cbs stuff suck less. For arm, csky, nds32, and riscv, just applied some renamed refactoring. Cc: Will Deacon <will@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Guo Ren <guoren@kernel.org> Cc: Nick Hu <redacted> Cc: Paul Walmsley <redacted> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: linux-arm-kernel@lists.infradead.org Cc: kvmarm@lists.cs.columbia.edu Cc: linux-csky@vger.kernel.org Cc: linux-riscv@lists.infradead.org Cc: xen-devel@lists.xenproject.org Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Original-by: Peter Zijlstra (Intel) [off-list ref] Signed-off-by: Like Xu <redacted> Signed-off-by: Zhu Lingshan <redacted> Reviewed-by: Boris Ostrovsky <redacted> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- arch/arm/kernel/perf_callchain.c | 16 +++++++----- arch/arm64/kernel/perf_callchain.c | 29 +++++++++++++++++----- arch/arm64/kvm/perf.c | 22 ++++++++--------- arch/csky/kernel/perf_callchain.c | 4 +-- arch/nds32/kernel/perf_event_cpu.c | 16 +++++++----- arch/riscv/kernel/perf_callchain.c | 4 +-- arch/x86/events/core.c | 39 ++++++++++++++++++++++++------ arch/x86/events/intel/core.c | 7 +++--- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/pmu.c | 2 +- arch/x86/kvm/x86.c | 37 +++++++++++++++------------- arch/x86/xen/pmu.c | 33 ++++++++++--------------- include/linux/perf_event.h | 12 ++++++--- kernel/events/core.c | 9 +++++++ 14 files changed, 144 insertions(+), 88 deletions(-)
diff --git a/arch/arm/kernel/perf_callchain.c b/arch/arm/kernel/perf_callchain.c
index 3b69a76d341e..1ce30f86d6c7 100644
--- a/arch/arm/kernel/perf_callchain.c
+++ b/arch/arm/kernel/perf_callchain.c@@ -64,7 +64,7 @@ perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs { struct frame_tail __user *tail; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (perf_guest_cbs && perf_guest_cbs->state()) { /* We don't support guest os callchain now */ return; }
@@ -100,7 +100,7 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re { struct stackframe fr; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (perf_guest_cbs && perf_guest_cbs->state()) { /* We don't support guest os callchain now */ return; }
@@ -111,8 +111,8 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re unsigned long perf_instruction_pointer(struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + if (perf_guest_cbs && perf_guest_cbs->state()) + return perf_guest_cbs->get_ip(); return instruction_pointer(regs); }
@@ -120,9 +120,13 @@ unsigned long perf_instruction_pointer(struct pt_regs *regs) unsigned long perf_misc_flags(struct pt_regs *regs) { int misc = 0; + unsigned int state = 0; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (perf_guest_cbs) + state = perf_guest_cbs->state(); + + if (perf_guest_cbs && state) { + if (state & PERF_GUEST_USER) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL;
diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_callchain.c
index 4a72c2727309..1b344e23fd2f 100644
--- a/arch/arm64/kernel/perf_callchain.c
+++ b/arch/arm64/kernel/perf_callchain.c@@ -5,6 +5,7 @@ * Copyright (C) 2015 ARM Limited */ #include <linux/perf_event.h> +#include <linux/static_call.h> #include <linux/uaccess.h> #include <asm/pointer_auth.h>
@@ -99,10 +100,25 @@ compat_user_backtrace(struct compat_frame_tail __user *tail, } #endif /* CONFIG_COMPAT */ +DEFINE_STATIC_CALL_RET0(arm64_guest_state, *(perf_guest_cbs->state)); +DEFINE_STATIC_CALL_RET0(arm64_guest_get_ip, *(perf_guest_cbs->get_ip)); + +void arch_perf_update_guest_cbs(void) +{ + static_call_update(arm64_guest_state, (void *)&__static_call_return0); + static_call_update(arm64_guest_get_ip, (void *)&__static_call_return0); + + if (perf_guest_cbs && perf_guest_cbs->state) + static_call_update(arm64_guest_state, perf_guest_cbs->state); + + if (perf_guest_cbs && perf_guest_cbs->get_ip) + static_call_update(arm64_guest_get_ip, perf_guest_cbs->get_ip); +} + void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (static_call(arm64_guest_state)()) { /* We don't support guest os callchain now */ return; }
@@ -149,7 +165,7 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, { struct stackframe frame; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (static_call(arm64_guest_state)()) { /* We don't support guest os callchain now */ return; }
@@ -160,8 +176,8 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, unsigned long perf_instruction_pointer(struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + if (static_call(arm64_guest_state)()) + return static_call(arm64_guest_get_ip)(); return instruction_pointer(regs); }
@@ -169,9 +185,10 @@ unsigned long perf_instruction_pointer(struct pt_regs *regs) unsigned long perf_misc_flags(struct pt_regs *regs) { int misc = 0; + unsigned int guest = static_call(arm64_guest_state)(); - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (guest) { + if (guest & PERF_GUEST_USER) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL;
diff --git a/arch/arm64/kvm/perf.c b/arch/arm64/kvm/perf.c
index 151c31fb9860..8a3387e58f42 100644
--- a/arch/arm64/kvm/perf.c
+++ b/arch/arm64/kvm/perf.c@@ -13,21 +13,20 @@ DEFINE_STATIC_KEY_FALSE(kvm_arm_pmu_available); -static int kvm_is_in_guest(void) -{ - return kvm_get_running_vcpu() != NULL; -} - -static int kvm_is_user_mode(void) +static unsigned int kvm_guest_state(void) { struct kvm_vcpu *vcpu; + unsigned int state = 0; + + if (kvm_get_running_vcpu()) + state |= PERF_GUEST_ACTIVE; vcpu = kvm_get_running_vcpu(); - if (vcpu) - return !vcpu_mode_priv(vcpu); + if (vcpu && !vcpu_mode_priv(vcpu)) + state |= PERF_GUEST_USER; - return 0; + return state; } static unsigned long kvm_get_guest_ip(void)
@@ -43,9 +42,8 @@ static unsigned long kvm_get_guest_ip(void) } static struct perf_guest_info_callbacks kvm_guest_cbs = { - .is_in_guest = kvm_is_in_guest, - .is_user_mode = kvm_is_user_mode, - .get_guest_ip = kvm_get_guest_ip, + .state = kvm_guest_state, + .get_ip = kvm_get_guest_ip, }; int kvm_perf_init(void)
diff --git a/arch/csky/kernel/perf_callchain.c b/arch/csky/kernel/perf_callchain.c
index ab55e98ee8f6..3e42239dd1b2 100644
--- a/arch/csky/kernel/perf_callchain.c
+++ b/arch/csky/kernel/perf_callchain.c@@ -89,7 +89,7 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry, unsigned long fp = 0; /* C-SKY does not support virtualization. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) + if (perf_guest_cbs && perf_guest_cbs->state()) return; fp = regs->regs[4];
@@ -113,7 +113,7 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct stackframe fr; /* C-SKY does not support virtualization. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (perf_guest_cbs && perf_guest_cbs->state()) { pr_warn("C-SKY does not support perf in guest mode!"); return; }
diff --git a/arch/nds32/kernel/perf_event_cpu.c b/arch/nds32/kernel/perf_event_cpu.c
index 0ce6f9f307e6..1dc32ba842ce 100644
--- a/arch/nds32/kernel/perf_event_cpu.c
+++ b/arch/nds32/kernel/perf_event_cpu.c@@ -1371,7 +1371,7 @@ perf_callchain_user(struct perf_callchain_entry_ctx *entry, leaf_fp = 0; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (perf_guest_cbs && perf_guest_cbs->state()) { /* We don't support guest os callchain now */ return; }
@@ -1481,7 +1481,7 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, { struct stackframe fr; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (perf_guest_cbs && perf_guest_cbs->state()) { /* We don't support guest os callchain now */ return; }
@@ -1494,8 +1494,8 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, unsigned long perf_instruction_pointer(struct pt_regs *regs) { /* However, NDS32 does not support virtualization */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + if (perf_guest_cbs && perf_guest_cbs->state()) + return perf_guest_cbs->get_ip(); return instruction_pointer(regs); }
@@ -1503,10 +1503,14 @@ unsigned long perf_instruction_pointer(struct pt_regs *regs) unsigned long perf_misc_flags(struct pt_regs *regs) { int misc = 0; + unsigned int state = 0; + + if (perf_guest_cbs) + state = perf_guest_cbs->state(); /* However, NDS32 does not support virtualization */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (perf_guest_cbs && state) { + if (state & PERF_GUEST_USER) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL;
diff --git a/arch/riscv/kernel/perf_callchain.c b/arch/riscv/kernel/perf_callchain.c
index 0bb1854dce83..ea63f70cae5d 100644
--- a/arch/riscv/kernel/perf_callchain.c
+++ b/arch/riscv/kernel/perf_callchain.c@@ -59,7 +59,7 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry, unsigned long fp = 0; /* RISC-V does not support perf in guest mode. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) + if (perf_guest_cbs && perf_guest_cbs->state()) return; fp = regs->s0;
@@ -79,7 +79,7 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { /* RISC-V does not support perf in guest mode. */ - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (perf_guest_cbs && perf_guest_cbs->state()) { pr_warn("RISC-V does not support perf in guest mode!"); return; }
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 1eb45139fcc6..9a908631f6cc 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c@@ -90,6 +90,28 @@ DEFINE_STATIC_CALL_NULL(x86_pmu_pebs_aliases, *x86_pmu.pebs_aliases); */ DEFINE_STATIC_CALL_RET0(x86_pmu_guest_get_msrs, *x86_pmu.guest_get_msrs); +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)); + +void arch_perf_update_guest_cbs(void) +{ + static_call_update(x86_guest_state, (void *)&__static_call_return0); + static_call_update(x86_guest_get_ip, (void *)&__static_call_return0); + static_call_update(x86_guest_handle_intel_pt_intr, (void *)&__static_call_return0); + + if (perf_guest_cbs && perf_guest_cbs->state) + static_call_update(x86_guest_state, perf_guest_cbs->state); + + if (perf_guest_cbs && perf_guest_cbs->get_ip) + static_call_update(x86_guest_get_ip, perf_guest_cbs->get_ip); + + if (perf_guest_cbs && perf_guest_cbs->handle_intel_pt_intr) { + static_call_update(x86_guest_handle_intel_pt_intr, + perf_guest_cbs->handle_intel_pt_intr); + } +} + u64 __read_mostly hw_cache_event_ids [PERF_COUNT_HW_CACHE_MAX] [PERF_COUNT_HW_CACHE_OP_MAX]
@@ -2764,7 +2786,7 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re struct unwind_state state; unsigned long addr; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (static_call(x86_guest_state)()) { /* TODO: We don't support guest os callchain now */ return; }
@@ -2867,7 +2889,7 @@ perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs struct stack_frame frame; const struct stack_frame __user *fp; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + if (static_call(x86_guest_state)()) { /* TODO: We don't support guest os callchain now */ return; }
@@ -2944,18 +2966,21 @@ static unsigned long code_segment_base(struct pt_regs *regs) unsigned long perf_instruction_pointer(struct pt_regs *regs) { - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) - return perf_guest_cbs->get_guest_ip(); + unsigned long ip = static_call(x86_guest_get_ip)(); + + if (likely(!ip)) + ip = regs->ip + code_segment_base(regs); - return regs->ip + code_segment_base(regs); + return ip; } unsigned long perf_misc_flags(struct pt_regs *regs) { + unsigned int guest = static_call(x86_guest_state)(); int misc = 0; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { - if (perf_guest_cbs->is_user_mode()) + if (guest) { + if (guest & PERF_GUEST_USER) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL;
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index fca7a6e2242f..fb1bd7a0e1a6 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c@@ -2782,6 +2782,8 @@ static void intel_pmu_reset(void) local_irq_restore(flags); } +DECLARE_STATIC_CALL(x86_guest_handle_intel_pt_intr, *(perf_guest_cbs->handle_intel_pt_intr)); + static int handle_pmi_common(struct pt_regs *regs, u64 status) { struct perf_sample_data data;
@@ -2852,10 +2854,7 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status) */ if (__test_and_clear_bit(GLOBAL_STATUS_TRACE_TOPAPMI_BIT, (unsigned long *)&status)) { handled++; - if (unlikely(perf_guest_cbs && perf_guest_cbs->is_in_guest() && - perf_guest_cbs->handle_intel_pt_intr)) - perf_guest_cbs->handle_intel_pt_intr(); - else + if (!static_call(x86_guest_handle_intel_pt_intr)()) intel_pt_interrupt(); }
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 974cbfb1eefe..128e2dd9c944 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h@@ -1884,7 +1884,7 @@ int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu); int kvm_complete_insn_gp(struct kvm_vcpu *vcpu, int err); void __kvm_request_immediate_exit(struct kvm_vcpu *vcpu); -int kvm_is_in_guest(void); +unsigned int kvm_guest_state(void); void __user *__x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size);
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 827886c12c16..2dcbd1b30004 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c@@ -87,7 +87,7 @@ static void kvm_perf_overflow_intr(struct perf_event *perf_event, * woken up. So we should wake it, but this is impossible from * NMI context. Do it from irq work instead. */ - if (!kvm_is_in_guest()) + if (!kvm_guest_state()) irq_work_queue(&pmc_to_pmu(pmc)->irq_work); else kvm_make_request(KVM_REQ_PMI, pmc->vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e5d5c5ed7dd4..efd11702465c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c@@ -8268,44 +8268,47 @@ static void kvm_timer_init(void) DEFINE_PER_CPU(struct kvm_vcpu *, current_vcpu); EXPORT_PER_CPU_SYMBOL_GPL(current_vcpu); -int kvm_is_in_guest(void) +unsigned int kvm_guest_state(void) { - return __this_cpu_read(current_vcpu) != NULL; -} - -static int kvm_is_user_mode(void) -{ - int user_mode = 3; + struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu); + unsigned int state = 0; - if (__this_cpu_read(current_vcpu)) - user_mode = static_call(kvm_x86_get_cpl)(__this_cpu_read(current_vcpu)); + if (vcpu) { + state |= PERF_GUEST_ACTIVE; + if (static_call(kvm_x86_get_cpl)(vcpu)) + state |= PERF_GUEST_USER; + } - return user_mode != 0; + return state; } -static unsigned long kvm_get_guest_ip(void) +static unsigned long kvm_guest_get_ip(void) { + struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu); unsigned long ip = 0; - if (__this_cpu_read(current_vcpu)) - ip = kvm_rip_read(__this_cpu_read(current_vcpu)); + if (vcpu) + ip = kvm_rip_read(vcpu); return ip; } -static void kvm_handle_intel_pt_intr(void) +static unsigned int kvm_handle_intel_pt_intr(void) { struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu); + if (!vcpu) + return 0; + kvm_make_request(KVM_REQ_PMI, vcpu); __set_bit(MSR_CORE_PERF_GLOBAL_OVF_CTRL_TRACE_TOPA_PMI_BIT, (unsigned long *)&vcpu->arch.pmu.global_status); + return 1; } static struct perf_guest_info_callbacks kvm_guest_cbs = { - .is_in_guest = kvm_is_in_guest, - .is_user_mode = kvm_is_user_mode, - .get_guest_ip = kvm_get_guest_ip, + .state = kvm_guest_state, + .get_ip = kvm_guest_get_ip, .handle_intel_pt_intr = kvm_handle_intel_pt_intr, };
diff --git a/arch/x86/xen/pmu.c b/arch/x86/xen/pmu.c
index e13b0b49fcdf..85c6e6f6f422 100644
--- a/arch/x86/xen/pmu.c
+++ b/arch/x86/xen/pmu.c@@ -413,34 +413,28 @@ int pmu_apic_update(uint32_t val) } /* perf callbacks */ -static int xen_is_in_guest(void) +static unsigned int xen_guest_state(void) { const struct xen_pmu_data *xenpmu_data = get_xenpmu_data(); + unsigned int state = 0; if (!xenpmu_data) { pr_warn_once("%s: pmudata not initialized\n", __func__); - return 0; + return state; } if (!xen_initial_domain() || (xenpmu_data->domain_id >= DOMID_SELF)) - return 0; + return state; - return 1; -} + state |= PERF_GUEST_ACTIVE; -static int xen_is_user_mode(void) -{ - const struct xen_pmu_data *xenpmu_data = get_xenpmu_data(); + if (xenpmu_data->pmu.pmu_flags & PMU_SAMPLE_PV) { + if (xenpmu_data->pmu.pmu_flags & PMU_SAMPLE_USER) + state |= PERF_GUEST_USER; + } else if (xenpmu_data->pmu.r.regs.cpl & 3) + state |= PERF_GUEST_USER; - if (!xenpmu_data) { - pr_warn_once("%s: pmudata not initialized\n", __func__); - return 0; - } - - if (xenpmu_data->pmu.pmu_flags & PMU_SAMPLE_PV) - return (xenpmu_data->pmu.pmu_flags & PMU_SAMPLE_USER); - else - return !!(xenpmu_data->pmu.r.regs.cpl & 3); + return state; } static unsigned long xen_get_guest_ip(void)
@@ -456,9 +450,8 @@ static unsigned long xen_get_guest_ip(void) } static struct perf_guest_info_callbacks xen_guest_cbs = { - .is_in_guest = xen_is_in_guest, - .is_user_mode = xen_is_user_mode, - .get_guest_ip = xen_get_guest_ip, + .state = xen_guest_state, + .get_ip = xen_get_guest_ip, }; /* Convert registers from Xen's format to Linux' */
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 2d510ad750ed..e823677a214c 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h@@ -26,11 +26,13 @@ # include <asm/local64.h> #endif +#define PERF_GUEST_ACTIVE 0x01 +#define PERF_GUEST_USER 0x02 + struct perf_guest_info_callbacks { - int (*is_in_guest)(void); - int (*is_user_mode)(void); - unsigned long (*get_guest_ip)(void); - void (*handle_intel_pt_intr)(void); + unsigned int (*state)(void); + unsigned long (*get_ip)(void); + unsigned int (*handle_intel_pt_intr)(void); }; #ifdef CONFIG_HAVE_HW_BREAKPOINT
@@ -1237,6 +1239,8 @@ extern void perf_event_bpf_event(struct bpf_prog *prog, u16 flags); extern struct perf_guest_info_callbacks *perf_guest_cbs; +extern void __weak arch_perf_update_guest_cbs(void); + extern int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks); extern int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks);
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 464917096e73..e466fc8176e1 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c@@ -6489,9 +6489,18 @@ static void perf_pending_event(struct irq_work *entry) */ struct perf_guest_info_callbacks *perf_guest_cbs; +/* explicitly use __weak to fix duplicate symbol error */ +void __weak arch_perf_update_guest_cbs(void) +{ +} + int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) { + if (WARN_ON_ONCE(perf_guest_cbs)) + return -EBUSY; + perf_guest_cbs = cbs; + arch_perf_update_guest_cbs(); return 0; } EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
--
2.27.0
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