KVM: x86: Add intr/vectoring info and error code to kvm_exit tracepoint

Extend the kvm_exit tracepoint to align it with kvm_nested_vmexit in
terms of what information is captured.  On SVM, add interrupt info and
error code, while on VMX it add IDT vectoring and error code.  This
sets the stage for macrofying the kvm_exit tracepoint definition so that
it can be reused for kvm_nested_vmexit without loss of information.

Opportunistically stuff a zero for VM_EXIT_INTR_INFO if the VM-Enter
failed, as the field is guaranteed to be invalid.  Note, it'd be
possible to further filter the interrupt/exception fields based on the
VM-Exit reason, but the helper is intended only for tracepoints, i.e.
an extra VMREAD or two is a non-issue, the failed VM-Enter case is just
low hanging fruit.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200923201349.16097-5-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -1143,7 +1143,12 @@ struct kvm_x86_ops {
 	/* Returns actual tsc_offset set in active VMCS */
 	u64 (*write_l1_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset);
 
-	void (*get_exit_info)(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2);
+	/*
+	 * Retrieve somewhat arbitrary exit information.  Intended to be used
+	 * only from within tracepoints to avoid VMREADs when tracing is off.
+	 */
+	void (*get_exit_info)(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2,
+			      u32 *exit_int_info, u32 *exit_int_info_err_code);
 
 	int (*check_intercept)(struct kvm_vcpu *vcpu,
 			       struct x86_instruction_info *info,

arch/x86/kvm/svm/svm.c

@@ -2965,12 +2965,19 @@ static void dump_vmcb(struct kvm_vcpu *vcpu)
 	       "excp_to:", save->last_excp_to);
 }
 
-static void svm_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2)
+static void svm_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2,
+			      u32 *intr_info, u32 *error_code)
 {
 	struct vmcb_control_area *control = &to_svm(vcpu)->vmcb->control;
 
 	*info1 = control->exit_info_1;
 	*info2 = control->exit_info_2;
+	*intr_info = control->exit_int_info;
+	if ((*intr_info & SVM_EXITINTINFO_VALID) &&
+	    (*intr_info & SVM_EXITINTINFO_VALID_ERR))
+		*error_code = control->exit_int_info_err;
+	else
+		*error_code = 0;
 }
 
 static int handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)

arch/x86/kvm/trace.h

@@ -248,6 +248,8 @@ TRACE_EVENT(kvm_exit,
 		__field(	u32,	        isa             )
 		__field(	u64,	        info1           )
 		__field(	u64,	        info2           )
+		__field(	u32,	        intr_info	)
+		__field(	u32,	        error_code	)
 		__field(	unsigned int,	vcpu_id         )
 	),
 
@@ -257,13 +259,17 @@ TRACE_EVENT(kvm_exit,
 		__entry->isa            = isa;
 		__entry->vcpu_id        = vcpu->vcpu_id;
 		kvm_x86_ops.get_exit_info(vcpu, &__entry->info1,
-					   &__entry->info2);
+					  &__entry->info2,
+					  &__entry->intr_info,
+					  &__entry->error_code);
 	),
 
-	TP_printk("vcpu %u reason %s%s%s rip 0x%lx info %llx %llx",
+	TP_printk("vcpu %u reason %s%s%s rip 0x%lx info1 0x%016llx "
+		  "info2 0x%016llx intr_info 0x%08x error_code 0x%08x",
 		  __entry->vcpu_id,
 		  kvm_print_exit_reason(__entry->exit_reason, __entry->isa),
-		  __entry->guest_rip, __entry->info1, __entry->info2)
+		  __entry->guest_rip, __entry->info1, __entry->info2,
+		  __entry->intr_info, __entry->error_code)
 );
 
 /*

arch/x86/kvm/vmx/vmx.c

@@ -5545,10 +5545,24 @@ static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = {
 static const int kvm_vmx_max_exit_handlers =
 	ARRAY_SIZE(kvm_vmx_exit_handlers);
 
-static void vmx_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2)
+static void vmx_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2,
+			      u32 *intr_info, u32 *error_code)
 {
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
+
 	*info1 = vmx_get_exit_qual(vcpu);
-	*info2 = vmx_get_intr_info(vcpu);
+	if (!(vmx->exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY)) {
+		*info2 = vmx->idt_vectoring_info;
+		*intr_info = vmx_get_intr_info(vcpu);
+		if (is_exception_with_error_code(*intr_info))
+			*error_code = vmcs_read32(VM_EXIT_INTR_ERROR_CODE);
+		else
+			*error_code = 0;
+	} else {
+		*info2 = 0;
+		*intr_info = 0;
+		*error_code = 0;
+	}
 }
 
 static void vmx_destroy_pml_buffer(struct vcpu_vmx *vmx)