KVM: x86: Add interrupt injection information to the kvm_entry tracepoint

Add VMX/SVM specific interrupt injection info the kvm_entry tracepoint.
As is done with kvm_exit, gather the information via a kvm_x86_ops hook
to avoid the moderately costly VMREADs on VMX when the tracepoint isn't
enabled.

Opportunistically rename the parameters in the get_exit_info()
declaration to match the names used by both SVM and VMX.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20240910200350.264245-2-mlevitsk@redhat.com
[sean: drop is_guest_mode() change, use intr_info/error_code for names]
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: Maxim Levitsky

arch/x86/include/asm/kvm-x86-ops.h

@@ -100,6 +100,7 @@ KVM_X86_OP(get_l2_tsc_multiplier)
 KVM_X86_OP(write_tsc_offset)
 KVM_X86_OP(write_tsc_multiplier)
 KVM_X86_OP(get_exit_info)
+KVM_X86_OP(get_entry_info)
 KVM_X86_OP(check_intercept)
 KVM_X86_OP(handle_exit_irqoff)
 KVM_X86_OP_OPTIONAL(update_cpu_dirty_logging)

arch/x86/include/asm/kvm_host.h

@@ -1770,12 +1770,15 @@ struct kvm_x86_ops {
 	void (*write_tsc_multiplier)(struct kvm_vcpu *vcpu);
 
 	/*
-	 * Retrieve somewhat arbitrary exit information.  Intended to
+	 * Retrieve somewhat arbitrary exit/entry information.  Intended to
 	 * be used only from within tracepoints or error paths.
 	 */
 	void (*get_exit_info)(struct kvm_vcpu *vcpu, u32 *reason,
 			      u64 *info1, u64 *info2,
-			      u32 *exit_int_info, u32 *exit_int_info_err_code);
+			      u32 *intr_info, u32 *error_code);
+
+	void (*get_entry_info)(struct kvm_vcpu *vcpu,
+			       u32 *intr_info, u32 *error_code);
 
 	int (*check_intercept)(struct kvm_vcpu *vcpu,
 			       struct x86_instruction_info *info,

arch/x86/kvm/svm/svm.c

@@ -3542,6 +3542,21 @@ static void svm_get_exit_info(struct kvm_vcpu *vcpu, u32 *reason,
 		*error_code = 0;
 }
 
+static void svm_get_entry_info(struct kvm_vcpu *vcpu, u32 *intr_info,
+			       u32 *error_code)
+{
+	struct vmcb_control_area *control = &to_svm(vcpu)->vmcb->control;
+
+	*intr_info = control->event_inj;
+
+	if ((*intr_info & SVM_EXITINTINFO_VALID) &&
+	    (*intr_info & SVM_EXITINTINFO_VALID_ERR))
+		*error_code = control->event_inj_err;
+	else
+		*error_code = 0;
+
+}
+
 static int svm_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -5082,6 +5097,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.required_apicv_inhibits = AVIC_REQUIRED_APICV_INHIBITS,
 
 	.get_exit_info = svm_get_exit_info,
+	.get_entry_info = svm_get_entry_info,
 
 	.vcpu_after_set_cpuid = svm_vcpu_after_set_cpuid,
 

arch/x86/kvm/trace.h

@@ -22,15 +22,22 @@ TRACE_EVENT(kvm_entry,
 		__field(	unsigned int,	vcpu_id		)
 		__field(	unsigned long,	rip		)
 		__field(	bool,		immediate_exit	)
+		__field(	u32,		intr_info	)
+		__field(	u32,		error_code	)
 	),
 
 	TP_fast_assign(
 		__entry->vcpu_id        = vcpu->vcpu_id;
 		__entry->rip		= kvm_rip_read(vcpu);
 		__entry->immediate_exit	= force_immediate_exit;
+
+		kvm_x86_call(get_entry_info)(vcpu, &__entry->intr_info,
+					     &__entry->error_code);
 	),
 
-	TP_printk("vcpu %u, rip 0x%lx%s", __entry->vcpu_id, __entry->rip,
+	TP_printk("vcpu %u, rip 0x%lx intr_info 0x%08x error_code 0x%08x%s",
+		  __entry->vcpu_id, __entry->rip,
+		  __entry->intr_info, __entry->error_code,
 		  __entry->immediate_exit ? "[immediate exit]" : "")
 );
 

arch/x86/kvm/vmx/main.c

@@ -111,6 +111,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.get_mt_mask = vmx_get_mt_mask,
 
 	.get_exit_info = vmx_get_exit_info,
+	.get_entry_info = vmx_get_entry_info,
 
 	.vcpu_after_set_cpuid = vmx_vcpu_after_set_cpuid,
 

arch/x86/kvm/vmx/vmx.c

@@ -6194,6 +6194,15 @@ void vmx_get_exit_info(struct kvm_vcpu *vcpu, u32 *reason,
 	}
 }
 
+void vmx_get_entry_info(struct kvm_vcpu *vcpu, u32 *intr_info, u32 *error_code)
+{
+	*intr_info = vmcs_read32(VM_ENTRY_INTR_INFO_FIELD);
+	if (is_exception_with_error_code(*intr_info))
+		*error_code = vmcs_read32(VM_ENTRY_EXCEPTION_ERROR_CODE);
+	else
+		*error_code = 0;
+}
+
 static void vmx_destroy_pml_buffer(struct vcpu_vmx *vmx)
 {
 	if (vmx->pml_pg) {

arch/x86/kvm/vmx/x86_ops.h

@@ -104,8 +104,11 @@ void vmx_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap);
 int vmx_set_tss_addr(struct kvm *kvm, unsigned int addr);
 int vmx_set_identity_map_addr(struct kvm *kvm, u64 ident_addr);
 u8 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
+
 void vmx_get_exit_info(struct kvm_vcpu *vcpu, u32 *reason,
 		       u64 *info1, u64 *info2, u32 *intr_info, u32 *error_code);
+void vmx_get_entry_info(struct kvm_vcpu *vcpu, u32 *intr_info, u32 *error_code);
+
 u64 vmx_get_l2_tsc_offset(struct kvm_vcpu *vcpu);
 u64 vmx_get_l2_tsc_multiplier(struct kvm_vcpu *vcpu);
 void vmx_write_tsc_offset(struct kvm_vcpu *vcpu);