[PATCH 1/7] KVM: x86: Add RIP to the kvm_entry, i.e. VM-Enter, tracepoint

Sean Christopherson
2020-07-18T06:39:47Z

Add RIP to the kvm_entry tracepoint to help debug if the kvm_exit
tracepoint is disable or if VM-Enter fails, in which case the kvm_exit
tracepoint won't be hit.

Read RIP from within the tracepoint itself to avoid a potential VMREAD
and retpoline if the guest's RIP isn't available.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/trace.h | 10 ++++++----
arch/x86/kvm/x86.c | 2 +-
2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index b66432b015d2e..9899ff0fa2534 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -15,18 +15,20 @@
* Tracepoint for guest mode entry.
*/
TRACE_EVENT(kvm_entry,
- TP_PROTO(unsigned int vcpu_id),
- TP_ARGS(vcpu_id),
+ TP_PROTO(struct kvm_vcpu *vcpu),
+ TP_ARGS(vcpu),

TP_STRUCT__entry(
__field( unsigned int, vcpu_id )
+ __field( unsigned long, rip )
),

TP_fast_assign(
- __entry->vcpu_id = vcpu_id;
+ __entry->vcpu_id = vcpu->vcpu_id;
+ __entry->rip = kvm_rip_read(vcpu);
),

- TP_printk("vcpu %u", __entry->vcpu_id)
+ TP_printk("vcpu %u, rip 0x%lx", __entry->vcpu_id, __entry->rip)
);

/*
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5f526d94c33f3..3563359316d64 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8547,7 +8547,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
kvm_x86_ops.request_immediate_exit(vcpu);
}

- trace_kvm_entry(vcpu->vcpu_id);
+ trace_kvm_entry(vcpu);

fpregs_assert_state_consistent();
if (test_thread_flag(TIF_NEED_FPU_LOAD))
--
2.26.0