Commit a61d7c54 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: x86: Trace re-injected exceptions 



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: default avatarSean Christopherson <seanjc@google.com>
Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: default avatarMaciej S. Szmigiero <maciej.szmigiero@oracle.com>
Message-Id: <25470690a38b4d2b32b6204875dd35676c65c9f2.1651440202.git.maciej.szmigiero@oracle.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 7e5b5ef8

arch/x86/kvm/trace.h

+8 −4
Original line number Diff line number Diff line
@@ -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]" : "")

);



/*

arch/x86/kvm/x86.c

+9 −7
Original line number Diff line number Diff line
@@ -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;

	}