Merge tag 'perf_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf updates from Borislav Petkov:
 "Cleanup of the perf/kvm interaction."

* tag 'perf_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Drop guest callback (un)register stubs
  KVM: arm64: Drop perf.c and fold its tiny bits of code into arm.c
  KVM: arm64: Hide kvm_arm_pmu_available behind CONFIG_HW_PERF_EVENTS=y
  KVM: arm64: Convert to the generic perf callbacks
  KVM: x86: Move Intel Processor Trace interrupt handler to vmx.c
  KVM: Move x86's perf guest info callbacks to generic KVM
  KVM: x86: More precisely identify NMI from guest when handling PMI
  KVM: x86: Drop current_vcpu for kvm_running_vcpu + kvm_arch_vcpu variable
  perf/core: Use static_call to optimize perf_guest_info_callbacks
  perf: Force architectures to opt-in to guest callbacks
  perf: Add wrappers for invoking guest callbacks
  perf/core: Rework guest callbacks to prepare for static_call support
  perf: Drop dead and useless guest "support" from arm, csky, nds32 and riscv
  perf: Stop pretending that perf can handle multiple guest callbacks
  KVM: x86: Register Processor Trace interrupt hook iff PT enabled in guest
  KVM: x86: Register perf callbacks after calling vendor's hardware_setup()
  perf: Protect perf_guest_cbs with RCU

Author: torvalds

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)
@@ -100,38 +95,23 @@ 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);
 }
 
 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;
 }

arch/arm64/include/asm/kvm_host.h

@@ -675,8 +675,15 @@ unsigned long kvm_mmio_read_buf(const void *buf, unsigned int len);
 int kvm_handle_mmio_return(struct kvm_vcpu *vcpu);
 int io_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa);
 
-int kvm_perf_init(void);
-int kvm_perf_teardown(void);
+/*
+ * Returns true if a Performance Monitoring Interrupt (PMI), a.k.a. perf event,
+ * arrived in guest context.  For arm64, any event that arrives while a vCPU is
+ * loaded is considered to be "in guest".
+ */
+static inline bool kvm_arch_pmi_in_guest(struct kvm_vcpu *vcpu)
+{
+	return IS_ENABLED(CONFIG_GUEST_PERF_EVENTS) && !!vcpu;
+}
 
 long kvm_hypercall_pv_features(struct kvm_vcpu *vcpu);
 gpa_t kvm_init_stolen_time(struct kvm_vcpu *vcpu);

arch/arm64/kernel/image-vars.h

@@ -102,7 +102,9 @@ KVM_NVHE_ALIAS(__stop___kvm_ex_table);
 KVM_NVHE_ALIAS(kvm_arm_hyp_percpu_base);
 
 /* PMU available static key */
+#ifdef CONFIG_HW_PERF_EVENTS
 KVM_NVHE_ALIAS(kvm_arm_pmu_available);
+#endif
 
 /* Position-independent library routines */
 KVM_NVHE_ALIAS_HYP(clear_page, __pi_clear_page);

arch/arm64/kernel/perf_callchain.c

@@ -102,7 +102,7 @@ compat_user_backtrace(struct compat_frame_tail __user *tail,
 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 (perf_guest_state()) {
 		/* We don't support guest os callchain now */
 		return;
 	}
@@ -141,7 +141,7 @@ static bool callchain_trace(void *data, unsigned long pc)
 void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
 			   struct pt_regs *regs)
 {
-	if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
+	if (perf_guest_state()) {
 		/* We don't support guest os callchain now */
 		return;
 	}
@@ -151,18 +151,19 @@ 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 (perf_guest_state())
+		return perf_guest_get_ip();
 
 	return instruction_pointer(regs);
 }
 
 unsigned long perf_misc_flags(struct pt_regs *regs)
 {
+	unsigned int guest_state = perf_guest_state();
 	int misc = 0;
 
-	if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
-		if (perf_guest_cbs->is_user_mode())
+	if (guest_state) {
+		if (guest_state & PERF_GUEST_USER)
 			misc |= PERF_RECORD_MISC_GUEST_USER;
 		else
 			misc |= PERF_RECORD_MISC_GUEST_KERNEL;

arch/arm64/kvm/Kconfig

@@ -39,6 +39,7 @@ 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.
 

arch/arm64/kvm/Makefile

@@ -12,7 +12,7 @@ obj-$(CONFIG_KVM) += hyp/
 
 kvm-y := $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o \
 	 $(KVM)/vfio.o $(KVM)/irqchip.o $(KVM)/binary_stats.o \
-	 arm.o mmu.o mmio.o psci.o perf.o hypercalls.o pvtime.o \
+	 arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
 	 inject_fault.o va_layout.o handle_exit.o \
 	 guest.o debug.o reset.o sys_regs.o \
 	 vgic-sys-reg-v3.o fpsimd.o pmu.o \

arch/arm64/kvm/arm.c

@@ -503,6 +503,13 @@ bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
 	return vcpu_mode_priv(vcpu);
 }
 
+#ifdef CONFIG_GUEST_PERF_EVENTS
+unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu)
+{
+	return *vcpu_pc(vcpu);
+}
+#endif
+
 /* Just ensure a guest exit from a particular CPU */
 static void exit_vm_noop(void *info)
 {
@@ -1775,7 +1782,8 @@ static int init_subsystems(void)
 	if (err)
 		goto out;
 
-	kvm_perf_init();
+	kvm_register_perf_callbacks(NULL);
+
 	kvm_sys_reg_table_init();
 
 out:
@@ -2163,7 +2171,7 @@ int kvm_arch_init(void *opaque)
 /* NOP: Compiling as a module not supported */
 void kvm_arch_exit(void)
 {
-	kvm_perf_teardown();
+	kvm_unregister_perf_callbacks();
 }
 
 static int __init early_kvm_mode_cfg(char *arg)

arch/arm64/kvm/perf.c

@@ -14,6 +14,8 @@
 #include <kvm/arm_pmu.h>
 #include <kvm/arm_vgic.h>
 
+DEFINE_STATIC_KEY_FALSE(kvm_arm_pmu_available);
+
 static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx);
 static void kvm_pmu_update_pmc_chained(struct kvm_vcpu *vcpu, u64 select_idx);
 static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc);

arch/arm64/kvm/pmu-emul.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);