MIPS: KVM: Add kvm_asid_change trace event

Add a trace event for guest ASID changes, replacing the existing
kvm_debug call.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/mips/kvm/emulate.c

@@ -1082,11 +1082,10 @@ enum emulation_result kvm_mips_emulate_CP0(u32 inst, u32 *opc, u32 cause,
 				if ((KSEGX(vcpu->arch.gprs[rt]) != CKSEG0) &&
 				    ((kvm_read_c0_guest_entryhi(cop0) &
 				      KVM_ENTRYHI_ASID) != nasid)) {
-					kvm_debug("MTCz, change ASID from %#lx to %#lx\n",
+					trace_kvm_asid_change(vcpu,
 						kvm_read_c0_guest_entryhi(cop0)
-						& KVM_ENTRYHI_ASID,
-						vcpu->arch.gprs[rt]
-						& KVM_ENTRYHI_ASID);
+							& KVM_ENTRYHI_ASID,
+						nasid);
 
 					/* Blow away the shadow host TLBs */
 					kvm_mips_flush_host_tlb(1);

arch/mips/kvm/trace.h

@@ -122,6 +122,28 @@ TRACE_EVENT(kvm_aux,
 		      __entry->pc)
 );
 
+TRACE_EVENT(kvm_asid_change,
+	    TP_PROTO(struct kvm_vcpu *vcpu, unsigned int old_asid,
+		     unsigned int new_asid),
+	    TP_ARGS(vcpu, old_asid, new_asid),
+	    TP_STRUCT__entry(
+			__field(unsigned long, pc)
+			__field(u8, old_asid)
+			__field(u8, new_asid)
+	    ),
+
+	    TP_fast_assign(
+			__entry->pc = vcpu->arch.pc;
+			__entry->old_asid = old_asid;
+			__entry->new_asid = new_asid;
+	    ),
+
+	    TP_printk("PC: 0x%08lx old: 0x%02x new: 0x%02x",
+		      __entry->pc,
+		      __entry->old_asid,
+		      __entry->new_asid)
+);
+
 #endif /* _TRACE_KVM_H */
 
 /* This part must be outside protection */