Re: [PATCH 7/8] KVM: x86: Trace re-injected exceptions

Maxim Levitsky
2022-04-04T12:14:24Z

On Sat, 2022-04-02 at 01:09 +0000, Sean Christopherson wrote:
> Trace exceptions that are re-injected, not just those that KVM is
> injecting for the first time. Debugging re-injection bugs is painful
> enough as is, not having visibility into what KVM is doing only makes
> things worse.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
> arch/x86/kvm/x86.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 7a066cf92692..384091600bc2 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -9382,6 +9382,10 @@ int kvm_check_nested_events(struct kvm_vcpu *vcpu)
>
> static void kvm_inject_exception(struct kvm_vcpu *vcpu)
> {
> + trace_kvm_inj_exception(vcpu->arch.exception.nr,
> + vcpu->arch.exception.has_error_code,
> + vcpu->arch.exception.error_code);
> +

Can we use a {new tracepoint / new parameter for this tracepoint} for this to avoid confusion?

Best regards,
Maxim Levitsky

> if (vcpu->arch.exception.error_code && !is_protmode(vcpu))
> vcpu->arch.exception.error_code = false;
> static_call(kvm_x86_queue_exception)(vcpu);
> @@ -9439,10 +9443,6 @@ static int inject_pending_event(struct kvm_vcpu *vcpu, bool *req_immediate_exit)
>
> /* try to inject new event if pending */
> if (vcpu->arch.exception.pending) {
> - trace_kvm_inj_exception(vcpu->arch.exception.nr,
> - vcpu->arch.exception.has_error_code,
> - vcpu->arch.exception.error_code);
> -
> vcpu->arch.exception.pending = false;
> vcpu->arch.exception.injected = true;
>