KVM: VMX: Move posted interrupt delivery code to common header

Move posted interrupt delivery code to common header so that TDX can
leverage it.

No functional change intended.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
[binbin: split into new patch]
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Reviewed-by: Chao Gao <chao.gao@intel.com>
Message-ID: <20250222014757.897978-4-binbin.wu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Author: yamahata

arch/x86/kvm/vmx/common.h

@@ -109,4 +109,71 @@ static inline int __vmx_handle_ept_violation(struct kvm_vcpu *vcpu, gpa_t gpa,
 	return kvm_mmu_page_fault(vcpu, gpa, error_code, NULL, 0);
 }
 
+static inline void kvm_vcpu_trigger_posted_interrupt(struct kvm_vcpu *vcpu,
+						     int pi_vec)
+{
+#ifdef CONFIG_SMP
+	if (vcpu->mode == IN_GUEST_MODE) {
+		/*
+		 * The vector of the virtual has already been set in the PIR.
+		 * Send a notification event to deliver the virtual interrupt
+		 * unless the vCPU is the currently running vCPU, i.e. the
+		 * event is being sent from a fastpath VM-Exit handler, in
+		 * which case the PIR will be synced to the vIRR before
+		 * re-entering the guest.
+		 *
+		 * When the target is not the running vCPU, the following
+		 * possibilities emerge:
+		 *
+		 * Case 1: vCPU stays in non-root mode. Sending a notification
+		 * event posts the interrupt to the vCPU.
+		 *
+		 * Case 2: vCPU exits to root mode and is still runnable. The
+		 * PIR will be synced to the vIRR before re-entering the guest.
+		 * Sending a notification event is ok as the host IRQ handler
+		 * will ignore the spurious event.
+		 *
+		 * Case 3: vCPU exits to root mode and is blocked. vcpu_block()
+		 * has already synced PIR to vIRR and never blocks the vCPU if
+		 * the vIRR is not empty. Therefore, a blocked vCPU here does
+		 * not wait for any requested interrupts in PIR, and sending a
+		 * notification event also results in a benign, spurious event.
+		 */
+
+		if (vcpu != kvm_get_running_vcpu())
+			__apic_send_IPI_mask(get_cpu_mask(vcpu->cpu), pi_vec);
+		return;
+	}
+#endif
+	/*
+	 * The vCPU isn't in the guest; wake the vCPU in case it is blocking,
+	 * otherwise do nothing as KVM will grab the highest priority pending
+	 * IRQ via ->sync_pir_to_irr() in vcpu_enter_guest().
+	 */
+	kvm_vcpu_wake_up(vcpu);
+}
+
+/*
+ * Post an interrupt to a vCPU's PIR and trigger the vCPU to process the
+ * interrupt if necessary.
+ */
+static inline void __vmx_deliver_posted_interrupt(struct kvm_vcpu *vcpu,
+						  struct pi_desc *pi_desc, int vector)
+{
+	if (pi_test_and_set_pir(vector, pi_desc))
+		return;
+
+	/* If a previous notification has sent the IPI, nothing to do.  */
+	if (pi_test_and_set_on(pi_desc))
+		return;
+
+	/*
+	 * The implied barrier in pi_test_and_set_on() pairs with the smp_mb_*()
+	 * after setting vcpu->mode in vcpu_enter_guest(), thus the vCPU is
+	 * guaranteed to see PID.ON=1 and sync the PIR to IRR if triggering a
+	 * posted interrupt "fails" because vcpu->mode != IN_GUEST_MODE.
+	 */
+	kvm_vcpu_trigger_posted_interrupt(vcpu, POSTED_INTR_VECTOR);
+}
+
 #endif /* __KVM_X86_VMX_COMMON_H */

arch/x86/kvm/vmx/vmx.c

@@ -4182,50 +4182,6 @@ void vmx_msr_filter_changed(struct kvm_vcpu *vcpu)
 		pt_update_intercept_for_msr(vcpu);
 }
 
-static inline void kvm_vcpu_trigger_posted_interrupt(struct kvm_vcpu *vcpu,
-						     int pi_vec)
-{
-#ifdef CONFIG_SMP
-	if (vcpu->mode == IN_GUEST_MODE) {
-		/*
-		 * The vector of the virtual has already been set in the PIR.
-		 * Send a notification event to deliver the virtual interrupt
-		 * unless the vCPU is the currently running vCPU, i.e. the
-		 * event is being sent from a fastpath VM-Exit handler, in
-		 * which case the PIR will be synced to the vIRR before
-		 * re-entering the guest.
-		 *
-		 * When the target is not the running vCPU, the following
-		 * possibilities emerge:
-		 *
-		 * Case 1: vCPU stays in non-root mode. Sending a notification
-		 * event posts the interrupt to the vCPU.
-		 *
-		 * Case 2: vCPU exits to root mode and is still runnable. The
-		 * PIR will be synced to the vIRR before re-entering the guest.
-		 * Sending a notification event is ok as the host IRQ handler
-		 * will ignore the spurious event.
-		 *
-		 * Case 3: vCPU exits to root mode and is blocked. vcpu_block()
-		 * has already synced PIR to vIRR and never blocks the vCPU if
-		 * the vIRR is not empty. Therefore, a blocked vCPU here does
-		 * not wait for any requested interrupts in PIR, and sending a
-		 * notification event also results in a benign, spurious event.
-		 */
-
-		if (vcpu != kvm_get_running_vcpu())
-			__apic_send_IPI_mask(get_cpu_mask(vcpu->cpu), pi_vec);
-		return;
-	}
-#endif
-	/*
-	 * The vCPU isn't in the guest; wake the vCPU in case it is blocking,
-	 * otherwise do nothing as KVM will grab the highest priority pending
-	 * IRQ via ->sync_pir_to_irr() in vcpu_enter_guest().
-	 */
-	kvm_vcpu_wake_up(vcpu);
-}
-
 static int vmx_deliver_nested_posted_interrupt(struct kvm_vcpu *vcpu,
 						int vector)
 {
@@ -4285,20 +4241,7 @@ static int vmx_deliver_posted_interrupt(struct kvm_vcpu *vcpu, int vector)
 	if (!vcpu->arch.apic->apicv_active)
 		return -1;
 
-	if (pi_test_and_set_pir(vector, &vt->pi_desc))
-		return 0;
-
-	/* If a previous notification has sent the IPI, nothing to do.  */
-	if (pi_test_and_set_on(&vt->pi_desc))
-		return 0;
-
-	/*
-	 * The implied barrier in pi_test_and_set_on() pairs with the smp_mb_*()
-	 * after setting vcpu->mode in vcpu_enter_guest(), thus the vCPU is
-	 * guaranteed to see PID.ON=1 and sync the PIR to IRR if triggering a
-	 * posted interrupt "fails" because vcpu->mode != IN_GUEST_MODE.
-	 */
-	kvm_vcpu_trigger_posted_interrupt(vcpu, POSTED_INTR_VECTOR);
+	__vmx_deliver_posted_interrupt(vcpu, &vt->pi_desc, vector);
 	return 0;
 }