[PATCH v3 2/3] RISC-V: KVM: add tracepoint for guest page faults

[wang.yechao255 at zte.com.cn]

From: Wang Yechao <wang.yechao255 at zte.com.cn>

Add the kvm_page_fault event tracepoint to count the number of KVM
guest page faults.

Signed-off-by: Wang Yechao <wang.yechao255 at zte.com.cn>
---
 arch/riscv/kvm/trace.h     | 25 +++++++++++++++++++++++++
 arch/riscv/kvm/vcpu_exit.c |  3 +++
 2 files changed, 28 insertions(+)

diff --git a/arch/riscv/kvm/trace.h b/arch/riscv/kvm/trace.h
index 3d54175d805c..9056cc9883cf 100644
--- a/arch/riscv/kvm/trace.h
+++ b/arch/riscv/kvm/trace.h
@@ -56,6 +56,31 @@ TRACE_EVENT(kvm_exit,
 		__entry->htinst)
 );

+/*
+ * Tracepoint for page fault.
+ */
+TRACE_EVENT(kvm_page_fault,
+	TP_PROTO(struct kvm_vcpu *vcpu, u64 fault_address, u64 error_code),
+	TP_ARGS(vcpu, fault_address, error_code),
+
+	TP_STRUCT__entry(
+		__field(unsigned int,   vcpu_id)
+		__field(u64,            fault_address)
+		__field(u64,            error_code)
+	),
+
+	TP_fast_assign(
+		__entry->vcpu_id        = vcpu->vcpu_id;
+		__entry->fault_address  = fault_address;
+		__entry->error_code     = error_code;
+	),
+
+	TP_printk("vcpu %u address 0x%016llx error_code 0x%llx",
+		__entry->vcpu_id,
+		__entry->fault_address,
+		__entry->error_code)
+);
+
 #endif /* _TRACE_RSICV_KVM_H */

 #undef TRACE_INCLUDE_PATH
diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
index 0bb0c51e3c89..57a21a246aa8 100644
--- a/arch/riscv/kvm/vcpu_exit.c
+++ b/arch/riscv/kvm/vcpu_exit.c
@@ -11,6 +11,7 @@
 #include <asm/insn-def.h>
 #include <asm/kvm_mmu.h>
 #include <asm/kvm_nacl.h>
+#include "trace.h"

 static int gstage_page_fault(struct kvm_vcpu *vcpu, struct kvm_run *run,
 			     struct kvm_cpu_trap *trap)
@@ -27,6 +28,8 @@ static int gstage_page_fault(struct kvm_vcpu *vcpu, struct kvm_run *run,
 	memslot = gfn_to_memslot(vcpu->kvm, gfn);
 	hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);

+	trace_kvm_page_fault(vcpu, fault_addr, trap->scause);
+
 	if (kvm_is_error_hva(hva) ||
 	    (trap->scause == EXC_STORE_GUEST_PAGE_FAULT && !writable)) {
 		switch (trap->scause) {
-- 
2.43.5