KVM: MMU: trace fast page fault

To see what happen on this path and help us to optimize it

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

2 files changed, 40 insertions, 0 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 8637bffbdb4a..28c8fbcc6763 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2776,6 +2776,8 @@ static bool fast_page_fault(struct kvm_vcpu *vcpu, gva_t gva, int level,
          */
         ret = fast_pf_fix_direct_spte(vcpu, iterator.sptep, spte);
 exit:
+        trace_fast_page_fault(vcpu, gva, error_code, iterator.sptep,
+                              spte, ret);
         walk_shadow_page_lockless_end(vcpu);
 
         return ret;
diff --git a/arch/x86/kvm/mmutrace.h b/arch/x86/kvm/mmutrace.h
index 89fb0e81322a..c364abc8d034 100644
--- a/arch/x86/kvm/mmutrace.h
+++ b/arch/x86/kvm/mmutrace.h
@@ -243,6 +243,44 @@ TRACE_EVENT(
         TP_printk("addr:%llx gfn %llx access %x", __entry->addr, __entry->gfn,
                   __entry->access)
 );
+
+#define __spte_satisfied(__spte)                                \
+        (__entry->retry && is_writable_pte(__entry->__spte))
+
+TRACE_EVENT(
+        fast_page_fault,
+        TP_PROTO(struct kvm_vcpu *vcpu, gva_t gva, u32 error_code,
+                 u64 *sptep, u64 old_spte, bool retry),
+        TP_ARGS(vcpu, gva, error_code, sptep, old_spte, retry),
+
+        TP_STRUCT__entry(
+                __field(int, vcpu_id)
+                __field(gva_t, gva)
+                __field(u32, error_code)
+                __field(u64 *, sptep)
+                __field(u64, old_spte)
+                __field(u64, new_spte)
+                __field(bool, retry)
+        ),
+
+        TP_fast_assign(
+                __entry->vcpu_id = vcpu->vcpu_id;
+                __entry->gva = gva;
+                __entry->error_code = error_code;
+                __entry->sptep = sptep;
+                __entry->old_spte = old_spte;
+                __entry->new_spte = *sptep;
+                __entry->retry = retry;
+        ),
+
+        TP_printk("vcpu %d gva %lx error_code %s sptep %p old %#llx"
+                  " new %llx spurious %d fixed %d", __entry->vcpu_id,
+                  __entry->gva, __print_flags(__entry->error_code, "|",
+                  kvm_mmu_trace_pferr_flags), __entry->sptep,
+                  __entry->old_spte, __entry->new_spte,
+                  __spte_satisfied(old_spte), __spte_satisfied(new_spte)
+        )
+);
 #endif /* _TRACE_KVMMMU_H */
 
 #undef TRACE_INCLUDE_PATH