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Commit ce1a5e60 authored by David Matlack's avatar David Matlack Committed by Paolo Bonzini
Browse files

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: default avatarDavid Matlack <dmatlack@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 09a0c3f1

arch/x86/kvm/trace.h

+37 −0
Original line number Diff line number Diff line
@@ -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 @@ TRACE_EVENT(kvm_ple_window, 
#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

arch/x86/kvm/x86.c

+2 −0
Original line number Diff line number Diff line
@@ -1661,6 +1661,8 @@ static int kvm_guest_time_update(struct kvm_vcpu *v) 


	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));