KVM: nVMX: Fix posted intr delivery when vcpu is in guest mode

The PI vector for L0 and L1 must be different. If dest vcpu0
is in guest mode while vcpu1 is delivering a non-nested PI to
vcpu0, there wont't be any vmexit so that the non-nested interrupt
will be delayed.
Signed-off-by: Wincy Van <fanwenyi0529@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx.c

@@ -4987,9 +4987,12 @@ static void vmx_complete_nested_posted_interrupt(struct kvm_vcpu *vcpu)
 	}
 }
 
-static inline bool kvm_vcpu_trigger_posted_interrupt(struct kvm_vcpu *vcpu)
+static inline bool kvm_vcpu_trigger_posted_interrupt(struct kvm_vcpu *vcpu,
+						     bool nested)
 {
 #ifdef CONFIG_SMP
+	int pi_vec = nested ? POSTED_INTR_NESTED_VECTOR : POSTED_INTR_VECTOR;
+
 	if (vcpu->mode == IN_GUEST_MODE) {
 		struct vcpu_vmx *vmx = to_vmx(vcpu);
 
@@ -5007,8 +5010,7 @@ static inline bool kvm_vcpu_trigger_posted_interrupt(struct kvm_vcpu *vcpu)
 		 */
 		WARN_ON_ONCE(pi_test_sn(&vmx->pi_desc));
 
-		apic->send_IPI_mask(get_cpu_mask(vcpu->cpu),
-				POSTED_INTR_VECTOR);
+		apic->send_IPI_mask(get_cpu_mask(vcpu->cpu), pi_vec);
 		return true;
 	}
 #endif
@@ -5023,7 +5025,7 @@ static int vmx_deliver_nested_posted_interrupt(struct kvm_vcpu *vcpu,
 	if (is_guest_mode(vcpu) &&
 	    vector == vmx->nested.posted_intr_nv) {
 		/* the PIR and ON have been set by L1. */
-		kvm_vcpu_trigger_posted_interrupt(vcpu);
+		kvm_vcpu_trigger_posted_interrupt(vcpu, true);
 		/*
 		 * If a posted intr is not recognized by hardware,
 		 * we will accomplish it in the next vmentry.
@@ -5057,7 +5059,7 @@ static void vmx_deliver_posted_interrupt(struct kvm_vcpu *vcpu, int vector)
 	if (pi_test_and_set_on(&vmx->pi_desc))
 		return;
 
-	if (!kvm_vcpu_trigger_posted_interrupt(vcpu))
+	if (!kvm_vcpu_trigger_posted_interrupt(vcpu, false))
 		kvm_vcpu_kick(vcpu);
 }
 
@@ -10064,13 +10066,9 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 
 	/* Posted interrupts setting is only taken from vmcs12.  */
 	if (nested_cpu_has_posted_intr(vmcs12)) {
-		/*
-		 * Note that we use L0's vector here and in
-		 * vmx_deliver_nested_posted_interrupt.
-		 */
 		vmx->nested.posted_intr_nv = vmcs12->posted_intr_nv;
 		vmx->nested.pi_pending = false;
-		vmcs_write16(POSTED_INTR_NV, POSTED_INTR_VECTOR);
+		vmcs_write16(POSTED_INTR_NV, POSTED_INTR_NESTED_VECTOR);
 	} else {
 		exec_control &= ~PIN_BASED_POSTED_INTR;
 	}
@@ -10941,7 +10939,9 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu,
 		 */
 		vmx_flush_tlb(vcpu);
 	}
-
+	/* Restore posted intr vector. */
+	if (nested_cpu_has_posted_intr(vmcs12))
+		vmcs_write16(POSTED_INTR_NV, POSTED_INTR_VECTOR);
 
 	vmcs_write32(GUEST_SYSENTER_CS, vmcs12->host_ia32_sysenter_cs);
 	vmcs_writel(GUEST_SYSENTER_ESP, vmcs12->host_ia32_sysenter_esp);