KVM: x86: Trace re-injected exceptions

stable inclusion
from stable-v5.10.154
commit e5d7c6786befe4aca0ba645dc5b836fc60ea733c
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I64YCB

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e5d7c6786befe4aca0ba645dc5b836fc60ea733c

--------------------------------

[ Upstream commit a61d7c54 ]

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: NSean Christopherson <seanjc@google.com>
Reviewed-by: NMaxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: NMaciej S. Szmigiero <maciej.szmigiero@oracle.com>
Message-Id: <25470690a38b4d2b32b6204875dd35676c65c9f2.1651440202.git.maciej.szmigiero@oracle.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Stable-dep-of: 5623f751 ("KVM: x86: Treat #DBs from the emulator as fault-like (code and DR7.GD=1)")
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NLipeng Sang <sanglipeng1@jd.com>

arch/x86/kvm/trace.h

@@ -304,25 +304,29 @@ 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

@@ -8589,6 +8589,11 @@ static void update_cr8_intercept(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;
 	kvm_x86_ops.queue_exception(vcpu);
@@ -8646,13 +8651,6 @@ static void 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);
@@ -8666,6 +8664,10 @@ static void 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;
 	}