KVM: MMU: add tracepoint for kvm_mmu_invalidate_all_pages

It is good for debug and development
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

arch/x86/kvm/mmu.c

@@ -4264,6 +4264,7 @@ static void kvm_zap_obsolete_pages(struct kvm *kvm)
 void kvm_mmu_invalidate_zap_all_pages(struct kvm *kvm)
 {
 	spin_lock(&kvm->mmu_lock);
+	trace_kvm_mmu_invalidate_zap_all_pages(kvm);
 	kvm->arch.mmu_valid_gen++;
 
 	kvm_zap_obsolete_pages(kvm);

arch/x86/kvm/mmutrace.h

@@ -276,6 +276,26 @@ TRACE_EVENT(
 		  __spte_satisfied(old_spte), __spte_satisfied(new_spte)
 	)
 );
+
+TRACE_EVENT(
+	kvm_mmu_invalidate_zap_all_pages,
+	TP_PROTO(struct kvm *kvm),
+	TP_ARGS(kvm),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, mmu_valid_gen)
+		__field(unsigned int, mmu_used_pages)
+	),
+
+	TP_fast_assign(
+		__entry->mmu_valid_gen = kvm->arch.mmu_valid_gen;
+		__entry->mmu_used_pages = kvm->arch.n_used_mmu_pages;
+	),
+
+	TP_printk("kvm-mmu-valid-gen %lx used_pages %x",
+		  __entry->mmu_valid_gen, __entry->mmu_used_pages
+	)
+);
 #endif /* _TRACE_KVMMMU_H */
 
 #undef TRACE_INCLUDE_PATH