diff mbox series

[04/15] perf: Force architectures to opt-in to guest callbacks

Message ID 20210827005718.585190-5-seanjc@google.com (mailing list archive)
State New, archived
Headers show
Series [01/15] KVM: x86: Register perf callbacks after calling vendor's hardware_setup() | expand

Commit Message

Sean Christopherson Aug. 27, 2021, 12:57 a.m. UTC 
Introduce HAVE_GUEST_PERF_EVENTS and require architectures to select it
to allow register guest callbacks in perf.  Future patches will convert
the callbacks to per-CPU definitions.  Rather than churn a bunch of arch
code (that was presumably copy+pasted from x86), remove it wholesale as
it's useless and at best wasting cycles.

Wrap even the stubs with an #ifdef to avoid an arch sneaking in a bogus
registration with CONFIG_PERF_EVENTS=n.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/arm/kernel/perf_callchain.c   | 28 ++++------------------------
 arch/arm64/Kconfig                 |  1 +
 arch/csky/kernel/perf_callchain.c  | 10 ----------
 arch/nds32/kernel/perf_event_cpu.c | 29 ++++-------------------------
 arch/riscv/kernel/perf_callchain.c | 10 ----------
 arch/x86/Kconfig                   |  1 +
 include/linux/perf_event.h         |  4 ++++
 init/Kconfig                       |  3 +++
 kernel/events/core.c               |  2 ++
 9 files changed, 19 insertions(+), 69 deletions(-)
diff mbox series

Patch

diff --git a/arch/arm/kernel/perf_callchain.c b/arch/arm/kernel/perf_callchain.c
index 3b69a76d341e..bc6b246ab55e 100644
--- a/arch/arm/kernel/perf_callchain.c
+++ b/arch/arm/kernel/perf_callchain.c
@@ -64,11 +64,6 @@  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()) {
-		/* We don't support guest os callchain now */
-		return;
-	}
-
 	perf_callchain_store(entry, regs->ARM_pc);
 
 	if (!current->mm)
@@ -100,20 +95,12 @@  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()) {
-		/* We don't support guest os callchain now */
-		return;
-	}
-
 	arm_get_current_stackframe(regs, &fr);
 	walk_stackframe(&fr, callchain_trace, 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();
-
 	return instruction_pointer(regs);
 }
 
@@ -121,17 +108,10 @@  unsigned long perf_misc_flags(struct pt_regs *regs)
 {
 	int misc = 0;
 
-	if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
-		if (perf_guest_cbs->is_user_mode())
-			misc |= PERF_RECORD_MISC_GUEST_USER;
-		else
-			misc |= PERF_RECORD_MISC_GUEST_KERNEL;
-	} else {
-		if (user_mode(regs))
-			misc |= PERF_RECORD_MISC_USER;
-		else
-			misc |= PERF_RECORD_MISC_KERNEL;
-	}
+	if (user_mode(regs))
+		misc |= PERF_RECORD_MISC_USER;
+	else
+		misc |= PERF_RECORD_MISC_KERNEL;
 
 	return misc;
 }
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index b5b13a932561..72a201a686c5 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -190,6 +190,7 @@  config ARM64
 	select HAVE_NMI
 	select HAVE_PATA_PLATFORM
 	select HAVE_PERF_EVENTS
+	select HAVE_GUEST_PERF_EVENTS
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
 	select HAVE_REGS_AND_STACK_ACCESS_API
diff --git a/arch/csky/kernel/perf_callchain.c b/arch/csky/kernel/perf_callchain.c
index ab55e98ee8f6..92057de08f4f 100644
--- a/arch/csky/kernel/perf_callchain.c
+++ b/arch/csky/kernel/perf_callchain.c
@@ -88,10 +88,6 @@  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())
-		return;
-
 	fp = regs->regs[4];
 	perf_callchain_store(entry, regs->pc);
 
@@ -112,12 +108,6 @@  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()) {
-		pr_warn("C-SKY does not support perf in guest mode!");
-		return;
-	}
-
 	fr.fp = regs->regs[4];
 	fr.lr = regs->lr;
 	walk_stackframe(&fr, entry);
diff --git a/arch/nds32/kernel/perf_event_cpu.c b/arch/nds32/kernel/perf_event_cpu.c
index 0ce6f9f307e6..a78a879e7ef1 100644
--- a/arch/nds32/kernel/perf_event_cpu.c
+++ b/arch/nds32/kernel/perf_event_cpu.c
@@ -1371,11 +1371,6 @@  perf_callchain_user(struct perf_callchain_entry_ctx *entry,
 
 	leaf_fp = 0;
 
-	if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
-		/* We don't support guest os callchain now */
-		return;
-	}
-
 	perf_callchain_store(entry, regs->ipc);
 	fp = regs->fp;
 	gp = regs->gp;
@@ -1481,10 +1476,6 @@  perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
 {
 	struct stackframe fr;
 
-	if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
-		/* We don't support guest os callchain now */
-		return;
-	}
 	fr.fp = regs->fp;
 	fr.lp = regs->lp;
 	fr.sp = regs->sp;
@@ -1493,10 +1484,6 @@  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();
-
 	return instruction_pointer(regs);
 }
 
@@ -1504,18 +1491,10 @@  unsigned long perf_misc_flags(struct pt_regs *regs)
 {
 	int misc = 0;
 
-	/* However, NDS32 does not support virtualization */
-	if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
-		if (perf_guest_cbs->is_user_mode())
-			misc |= PERF_RECORD_MISC_GUEST_USER;
-		else
-			misc |= PERF_RECORD_MISC_GUEST_KERNEL;
-	} else {
-		if (user_mode(regs))
-			misc |= PERF_RECORD_MISC_USER;
-		else
-			misc |= PERF_RECORD_MISC_KERNEL;
-	}
+	if (user_mode(regs))
+		misc |= PERF_RECORD_MISC_USER;
+	else
+		misc |= PERF_RECORD_MISC_KERNEL;
 
 	return misc;
 }
diff --git a/arch/riscv/kernel/perf_callchain.c b/arch/riscv/kernel/perf_callchain.c
index 0bb1854dce83..1fc075b8f764 100644
--- a/arch/riscv/kernel/perf_callchain.c
+++ b/arch/riscv/kernel/perf_callchain.c
@@ -58,10 +58,6 @@  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())
-		return;
-
 	fp = regs->s0;
 	perf_callchain_store(entry, regs->epc);
 
@@ -78,11 +74,5 @@  static bool fill_callchain(void *entry, unsigned long pc)
 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()) {
-		pr_warn("RISC-V does not support perf in guest mode!");
-		return;
-	}
-
 	walk_stackframe(NULL, regs, fill_callchain, entry);
 }
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 49270655e827..a4de4aa7a3df 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -229,6 +229,7 @@  config X86
 	select HAVE_PERF_EVENTS
 	select HAVE_PERF_EVENTS_NMI
 	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
+	select HAVE_GUEST_PERF_EVENTS
 	select HAVE_PCI
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 05c0efba3cd1..5eab690622ca 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1236,9 +1236,11 @@  extern void perf_event_bpf_event(struct bpf_prog *prog,
 				 enum perf_bpf_event_type type,
 				 u16 flags);
 
+#ifdef CONFIG_HAVE_GUEST_PERF_EVENTS
 extern struct perf_guest_info_callbacks *perf_guest_cbs;
 extern void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks);
 extern void perf_unregister_guest_info_callbacks(void);
+#endif /* CONFIG_HAVE_GUEST_PERF_EVENTS */
 
 extern void perf_event_exec(void);
 extern void perf_event_comm(struct task_struct *tsk, bool exec);
@@ -1481,9 +1483,11 @@  perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)	{ }
 static inline void
 perf_bp_event(struct perf_event *event, void *data)			{ }
 
+#ifdef CONFIG_HAVE_GUEST_PERF_EVENTS
 static inline void perf_register_guest_info_callbacks
 (struct perf_guest_info_callbacks *callbacks)				{ }
 static inline void perf_unregister_guest_info_callbacks(void)		{ }
+#endif
 
 static inline void perf_event_mmap(struct vm_area_struct *vma)		{ }
 
diff --git a/init/Kconfig b/init/Kconfig
index 55f9f7738ebb..9ef51ae53977 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1776,6 +1776,9 @@  config HAVE_PERF_EVENTS
 	help
 	  See tools/perf/design.txt for details.
 
+config HAVE_GUEST_PERF_EVENTS
+	bool
+
 config PERF_USE_VMALLOC
 	bool
 	help
diff --git a/kernel/events/core.c b/kernel/events/core.c
index baae796612b9..9820df7ee455 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_HAVE_GUEST_PERF_EVENTS
 struct perf_guest_info_callbacks *perf_guest_cbs;
 
 void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
@@ -6495,6 +6496,7 @@  void perf_unregister_guest_info_callbacks(void)
 	perf_guest_cbs = NULL;
 }
 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
+#endif
 
 static void
 perf_output_sample_regs(struct perf_output_handle *handle,