[v1,2/3] KVM: arm64: Add trace events with field 'vcpu_id'

Commit Message

Leo Yan Nov. 5, 2022, 7:23 a.m. UTC

The existed trace events kvm_entry and kvm_exit don't contain the info
for virtual CPU id, thus the perf tool has no chance to do statistics
based on virtual CPU wise; and the trace events are ABI and we cannot
change it to avoid ABI breakage.

For above reasons, this patch adds two trace events kvm_entry_v2 and
kvm_exit_v2 with a new field 'vcpu_id'.  To support both the old and
new events, we use the tracepoint callback to check if any event is
enabled or not, if it's enabled then the callback will invoke the
corresponding trace event.

Signed-off-by: Leo Yan <[e-mail]>
---
 arch/arm64/kvm/trace.c     |  6 +++++
 arch/arm64/kvm/trace_arm.h | 45 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)

Patch

diff --git a/arch/arm64/kvm/trace.c b/arch/arm64/kvm/trace.c
index d25a3db994e2..d9b2587c77c3 100644
--- a/arch/arm64/kvm/trace.c
+++ b/arch/arm64/kvm/trace.c
@@ -10,6 +10,9 @@  static void kvm_entry_tp(void *data, struct kvm_vcpu *vcpu)
 {
 	if (trace_kvm_entry_enabled())
 		trace_kvm_entry(*vcpu_pc(vcpu));
+
+	if (trace_kvm_entry_v2_enabled())
+		trace_kvm_entry_v2(vcpu);
 }
 
 static void kvm_exit_tp(void *data, int ret, struct kvm_vcpu *vcpu)
@@ -17,6 +20,9 @@  static void kvm_exit_tp(void *data, int ret, struct kvm_vcpu *vcpu)
 	if (trace_kvm_exit_enabled())
 		trace_kvm_exit(ret, kvm_vcpu_trap_get_class(vcpu),
 			       *vcpu_pc(vcpu));
+
+	if (trace_kvm_exit_v2_enabled())
+		trace_kvm_exit_v2(ret, vcpu);
 }
 
 static int __init kvm_tp_init(void)
diff --git a/arch/arm64/kvm/trace_arm.h b/arch/arm64/kvm/trace_arm.h
index ef02ae93b28b..932c9d0c36f3 100644
--- a/arch/arm64/kvm/trace_arm.h
+++ b/arch/arm64/kvm/trace_arm.h
@@ -4,6 +4,7 @@ 
 
 #include <kvm/arm_arch_timer.h>
 #include <linux/tracepoint.h>
+#include <asm/kvm_emulate.h>
 
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM kvm
@@ -30,6 +31,23 @@  TRACE_EVENT(kvm_entry,
 	TP_printk("PC: 0x%016lx", __entry->vcpu_pc)
 );
 
+TRACE_EVENT(kvm_entry_v2,
+	TP_PROTO(struct kvm_vcpu *vcpu),
+	TP_ARGS(vcpu),
+
+	TP_STRUCT__entry(
+		__field(	unsigned int,	vcpu_id		)
+		__field(	unsigned long,	vcpu_pc		)
+	),
+
+	TP_fast_assign(
+		__entry->vcpu_id		= vcpu->vcpu_id;
+		__entry->vcpu_pc		= *vcpu_pc(vcpu);
+	),
+
+	TP_printk("vcpu: %u PC: 0x%016lx", __entry->vcpu_id, __entry->vcpu_pc)
+);
+
 DECLARE_TRACE(kvm_exit_tp,
 	TP_PROTO(int ret, struct kvm_vcpu *vcpu),
 	TP_ARGS(ret, vcpu));
@@ -57,6 +75,33 @@  TRACE_EVENT(kvm_exit,
 		  __entry->vcpu_pc)
 );
 
+TRACE_EVENT(kvm_exit_v2,
+	TP_PROTO(int ret, struct kvm_vcpu *vcpu),
+	TP_ARGS(ret, vcpu),
+
+	TP_STRUCT__entry(
+		__field(	unsigned int,	vcpu_id		)
+		__field(	int,		ret		)
+		__field(	unsigned int,	esr_ec		)
+		__field(	unsigned long,	vcpu_pc		)
+	),
+
+	TP_fast_assign(
+		__entry->vcpu_id		= vcpu->vcpu_id;
+		__entry->ret			= ARM_EXCEPTION_CODE(ret);
+		__entry->esr_ec			= ARM_EXCEPTION_IS_TRAP(ret) ?
+						  kvm_vcpu_trap_get_class(vcpu): 0;
+		__entry->vcpu_pc		= *vcpu_pc(vcpu);
+	),
+
+	TP_printk("%s: vcpu: %u HSR_EC: 0x%04x (%s), PC: 0x%016lx",
+		  __print_symbolic(__entry->ret, kvm_arm_exception_type),
+		  __entry->vcpu_id,
+		  __entry->esr_ec,
+		  __print_symbolic(__entry->esr_ec, kvm_arm_exception_class),
+		  __entry->vcpu_pc)
+);
+
 TRACE_EVENT(kvm_guest_fault,
 	TP_PROTO(unsigned long vcpu_pc, unsigned long hsr,
 		 unsigned long hxfar,