KVM: MMU: add tracepoint for check_mmio_spte

It is useful for debug mmio spte invalidation

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

2 files changed, 31 insertions, 2 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 3e893cd90389..417f36b7c0e4 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -283,8 +283,13 @@ static bool set_mmio_spte(struct kvm *kvm, u64 *sptep, gfn_t gfn,
 
 static bool check_mmio_spte(struct kvm *kvm, u64 spte)
 {
-        return likely(get_mmio_spte_generation(spte) ==
-                        kvm_current_mmio_generation(kvm));
+        unsigned int kvm_gen, spte_gen;
+
+        kvm_gen = kvm_current_mmio_generation(kvm);
+        spte_gen = get_mmio_spte_generation(spte);
+
+        trace_check_mmio_spte(spte, kvm_gen, spte_gen);
+        return likely(kvm_gen == spte_gen);
 }
 
 static inline u64 rsvd_bits(int s, int e)
diff --git a/arch/x86/kvm/mmutrace.h b/arch/x86/kvm/mmutrace.h
index ad24757041ad..9d2e0ffcb190 100644
--- a/arch/x86/kvm/mmutrace.h
+++ b/arch/x86/kvm/mmutrace.h
@@ -298,6 +298,30 @@ TRACE_EVENT(
                   __entry->mmu_valid_gen, __entry->mmu_used_pages
         )
 );
+
+
+TRACE_EVENT(
+        check_mmio_spte,
+        TP_PROTO(u64 spte, unsigned int kvm_gen, unsigned int spte_gen),
+        TP_ARGS(spte, kvm_gen, spte_gen),
+
+        TP_STRUCT__entry(
+                __field(unsigned int, kvm_gen)
+                __field(unsigned int, spte_gen)
+                __field(u64, spte)
+        ),
+
+        TP_fast_assign(
+                __entry->kvm_gen = kvm_gen;
+                __entry->spte_gen = spte_gen;
+                __entry->spte = spte;
+        ),
+
+        TP_printk("spte %llx kvm_gen %x spte-gen %x valid %d", __entry->spte,
+                  __entry->kvm_gen, __entry->spte_gen,
+                  __entry->kvm_gen == __entry->spte_gen
+        )
+);
 #endif /* _TRACE_KVMMMU_H */
 
 #undef TRACE_INCLUDE_PATH