Patch "KVM: x86: Trace re-injected exceptions" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    KVM: x86: Trace re-injected exceptions

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     kvm-x86-trace-re-injected-exceptions.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit a467d873bcb9e4b1b756937e6d6d02f7ce6283e8
Author: Sean Christopherson <seanjc@xxxxxxxxxx>
Date:   Mon May 2 00:07:31 2022 +0200

    KVM: x86: Trace re-injected exceptions
    
    [ Upstream commit a61d7c5432ac5a953bbcec17af031661c2bd201d ]
    
    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@xxxxxxxxxx>
    Reviewed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
    Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@xxxxxxxxxx>
    Message-Id: <25470690a38b4d2b32b6204875dd35676c65c9f2.1651440202.git.maciej.szmigiero@xxxxxxxxxx>
    Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
    Stable-dep-of: 5623f751bd9c ("KVM: x86: Treat #DBs from the emulator as fault-like (code and DR7.GD=1)")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 03ebe368333e..c41506ed8c7d 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -355,25 +355,29 @@ 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]" : "")
 );
 
 /*
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8648799d48f8..c171ca2bb85a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9010,6 +9010,11 @@ 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);
@@ -9067,13 +9072,6 @@ 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);
@@ -9087,6 +9085,10 @@ 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;
 	}