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KVM: x86: Trace re-injected exceptions

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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.

Delay propagating pending=>injected in the non-reinjection path so that
the tracing can properly identify reinjected exceptions.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Message-Id: <25470690a38b4d2b32b6204875dd35676c65c9f2.1651440202.git.maciej.szmigiero@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2022-05-02 00:07:31 +02:00 • committed by Paolo Bonzini
parent 7e5b5ef8dc
commit a61d7c5432
2 changed files with 17 additions and 11 deletions
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12
arch/x86/kvm/trace.h
View file

@ -358,25 +358,29 @@ TRACE_EVENT(kvm_inj_virq,
* Tracepoint for kvm interrupt injection:
*/
TRACE_EVENT(kvm_inj_exception,
TP_PROTO(unsigned exception, bool has_error, unsigned error_code),
TP_ARGS(exception, has_error, error_code),
TP_PROTO(unsigned exception, bool has_error, unsigned error_code,
bool reinjected),
TP_ARGS(exception, has_error, error_code, reinjected),
TP_STRUCT__entry(
__field( u8, exception )
__field( u8, has_error )
__field( u32, error_code )
__field( bool, reinjected )
),
TP_fast_assign(
__entry->exception = exception;
__entry->has_error = has_error;
__entry->error_code = error_code;
__entry->reinjected = reinjected;
),
TP_printk("%s (0x%x)",
TP_printk("%s (0x%x)%s",
__print_symbolic(__entry->exception, kvm_trace_sym_exc),
/* FIXME: don't print error_code if not present */
__entry->has_error ? __entry->error_code : 0)
__entry->has_error ? __entry->error_code : 0,
__entry->reinjected ? " [reinjected]" : "")
);
/*

16
arch/x86/kvm/x86.c
View file

@ -9408,6 +9408,11 @@ 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,
vcpu->arch.exception.injected);
if (vcpu->arch.exception.error_code && !is_protmode(vcpu))
vcpu->arch.exception.error_code = false;
static_call(kvm_x86_queue_exception)(vcpu);
@ -9465,13 +9470,6 @@ 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;
if (exception_type(vcpu->arch.exception.nr) == EXCPT_FAULT)
__kvm_set_rflags(vcpu, kvm_get_rflags(vcpu) |
X86_EFLAGS_RF);
@ -9485,6 +9483,10 @@ static int inject_pending_event(struct kvm_vcpu *vcpu, bool *req_immediate_exit)
}
kvm_inject_exception(vcpu);
vcpu->arch.exception.pending = false;
vcpu->arch.exception.injected = true;
can_inject = false;
}