Thread (1 message) 1 message, 1 author, 2021-07-22
STALE1783d REVIEWED: 1 (0M)
Revisions (4)
  1. v7 [diff vs current]
  2. v8 [diff vs current]
  3. v9 current
  4. v10 [diff vs current]

[PATCH V9 01/18] perf/core: Use static_call to optimize perf_guest_info_callbacks

From: Zhu Lingshan <hidden>
Date: 2021-07-22 05:42:38
Also in: kvm, kvmarm, linux-riscv, lkml, xen-devel
Subsystem: arm pmu profiling and debugging, arm port, arm64 port (aarch64 architecture), c-sky architecture, kernel virtual machine for arm64 (kvm/arm64), kernel virtual machine for x86 (kvm/x86), performance events subsystem, risc-v architecture, the rest, x86 architecture (32-bit and 64-bit), xen hypervisor x86 · Maintainers: Will Deacon, Mark Rutland, Russell King, Catalin Marinas, Guo Ren, Marc Zyngier, Oliver Upton, Sean Christopherson, Paolo Bonzini, Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Paul Walmsley, Palmer Dabbelt, Albert Ou, Linus Torvalds, Thomas Gleixner, Borislav Petkov, Dave Hansen, Juergen Gross

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>
---
 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 c6dc1b445231..429cb4c22097 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8259,44 +8259,47 @@ 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


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help