kvm: x86: add trace event for pvclock updates
The new trace event records:
* the id of vcpu being updated
* the pvclock_vcpu_time_info struct being written to guest memory
This is useful for debugging pvclock bugs, such as the bug fixed by
"[PATCH] kvm: x86: Fix kvm clock versioning.".
Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 6b06ab8..c2a34bb 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -5,6 +5,7 @@
#include <asm/vmx.h>
#include <asm/svm.h>
#include <asm/clocksource.h>
+#include <asm/pvclock-abi.h>
#undef TRACE_SYSTEM
#define TRACE_SYSTEM kvm
@@ -877,6 +878,42 @@
#define trace_kvm_ple_window_shrink(vcpu_id, new, old) \
trace_kvm_ple_window(false, vcpu_id, new, old)
+TRACE_EVENT(kvm_pvclock_update,
+ TP_PROTO(unsigned int vcpu_id, struct pvclock_vcpu_time_info *pvclock),
+ TP_ARGS(vcpu_id, pvclock),
+
+ TP_STRUCT__entry(
+ __field( unsigned int, vcpu_id )
+ __field( __u32, version )
+ __field( __u64, tsc_timestamp )
+ __field( __u64, system_time )
+ __field( __u32, tsc_to_system_mul )
+ __field( __s8, tsc_shift )
+ __field( __u8, flags )
+ ),
+
+ TP_fast_assign(
+ __entry->vcpu_id = vcpu_id;
+ __entry->version = pvclock->version;
+ __entry->tsc_timestamp = pvclock->tsc_timestamp;
+ __entry->system_time = pvclock->system_time;
+ __entry->tsc_to_system_mul = pvclock->tsc_to_system_mul;
+ __entry->tsc_shift = pvclock->tsc_shift;
+ __entry->flags = pvclock->flags;
+ ),
+
+ TP_printk("vcpu_id %u, pvclock { version %u, tsc_timestamp 0x%llx, "
+ "system_time 0x%llx, tsc_to_system_mul 0x%x, tsc_shift %d, "
+ "flags 0x%x }",
+ __entry->vcpu_id,
+ __entry->version,
+ __entry->tsc_timestamp,
+ __entry->system_time,
+ __entry->tsc_to_system_mul,
+ __entry->tsc_shift,
+ __entry->flags)
+);
+
#endif /* _TRACE_KVM_H */
#undef TRACE_INCLUDE_PATH
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8bf37d0..f85da5c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1661,6 +1661,8 @@
vcpu->hv_clock.flags = pvclock_flags;
+ trace_kvm_pvclock_update(v->vcpu_id, &vcpu->hv_clock);
+
kvm_write_guest_cached(v->kvm, &vcpu->pv_time,
&vcpu->hv_clock,
sizeof(vcpu->hv_clock));