[PATCH v6 5/5] KVM : VMX: Use posted interrupt to deliver virtual interrupt

[Yang Zhang <yang.z.zhang@intel.com>]

From: Yang Zhang <yang.z.zhang@Intel.com>

If posted interrupt is avaliable, then uses it to inject virtual
interrupt to guest.

Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
---
 arch/x86/kvm/irq.c   |    3 ++-
 arch/x86/kvm/lapic.c |   16 +++++++++++++---
 arch/x86/kvm/lapic.h |    1 +
 arch/x86/kvm/vmx.c   |   11 +++++++++++
 arch/x86/kvm/x86.c   |    4 ++++
 5 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c
index 484bc87..5179988 100644
--- a/arch/x86/kvm/irq.c
+++ b/arch/x86/kvm/irq.c
@@ -81,7 +81,8 @@ int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
 	if (kvm_cpu_has_extint(v))
 		return 1;
 
-	return kvm_apic_has_interrupt(v) != -1;	/* LAPIC */
+	return (kvm_apic_has_interrupt(v) != -1) ||
+		kvm_hwapic_has_interrupt(v);
 }
 EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
 
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index b3ea50e..46c7310 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -713,7 +713,10 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
 		} else
 			apic_clear_vector(vector, apic->regs + APIC_TMR);
 
-		result = !apic_test_and_set_irr(vector, apic);
+		result = 1;
+		if (!kvm_x86_ops->deliver_posted_interrupt(vcpu, vector))
+			result = !apic_test_and_set_irr(vector, apic);
+
 		trace_kvm_apic_accept_irq(vcpu->vcpu_id, delivery_mode,
 					  trig_mode, vector, !result);
 		if (!result) {
@@ -723,8 +726,10 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
 			break;
 		}
 
-		kvm_make_request(KVM_REQ_EVENT, vcpu);
-		kvm_vcpu_kick(vcpu);
+		if (!kvm_x86_ops->vm_has_apicv(vcpu->kvm)) {
+			kvm_make_request(KVM_REQ_EVENT, vcpu);
+			kvm_vcpu_kick(vcpu);
+		}
 		break;
 
 	case APIC_DM_REMRD:
@@ -1604,6 +1609,11 @@ int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu)
 	return highest_irr;
 }
 
+bool kvm_hwapic_has_interrupt(struct kvm_vcpu *vcpu)
+{
+	return kvm_x86_ops->hwapic_has_interrupt(vcpu);
+}
+
 int kvm_apic_accept_pic_intr(struct kvm_vcpu *vcpu)
 {
 	u32 lvt0 = kvm_apic_get_reg(vcpu->arch.apic, APIC_LVT0);
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index e5327be..c6abc63 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -37,6 +37,7 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu);
 void kvm_free_lapic(struct kvm_vcpu *vcpu);
 
 int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu);
+bool kvm_hwapic_has_interrupt(struct kvm_vcpu *vcpu);
 int kvm_apic_accept_pic_intr(struct kvm_vcpu *vcpu);
 int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu);
 void kvm_lapic_reset(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 0b5a8ae..48a2239 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3932,6 +3932,17 @@ static void vmx_posted_intr_clear_on(struct kvm_vcpu *vcpu)
 	clear_bit(POSTED_INTR_ON, (unsigned long *)&vmx->pi_desc.u.control);
 }
 
+/*
+ * Send interrupt to vcpu via posted interrupt way.
+ * Return false if posted interrupt is not supported and the caller will
+ * roll back to old way(via set vIRR).
+ * Return true if posted interrupt is avalialbe, the interrupt is set
+ * in pir(posted interrupt requests):
+ * 1. If target vcpu is running(non-root mode), send posted interrupt
+ * notification to vcpu and hardware will sync pir to vIRR atomically.
+ * 2. If target vcpu isn't running(root mode), kick it to pick up the
+ * interrupt from pir in next vmentry.
+ */
 static bool vmx_deliver_posted_interrupt(struct kvm_vcpu *vcpu, int vector)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0baa90d..0981100 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2679,6 +2679,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,
 				    struct kvm_lapic_state *s)
 {
+	kvm_x86_ops->sync_pir_to_irr(vcpu);
 	memcpy(s->regs, vcpu->arch.apic->regs, sizeof *s);
 
 	return 0;
@@ -5699,6 +5700,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	}
 
 	if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) {
+		kvm_x86_ops->sync_pir_to_irr(vcpu);
 		inject_pending_event(vcpu);
 
 		/* enable NMI/IRQ window open exits if needed */
@@ -5741,6 +5743,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 
 	local_irq_disable();
 
+	kvm_x86_ops->posted_intr_clear_on(vcpu);
+
 	if (vcpu->mode == EXITING_GUEST_MODE || vcpu->requests
 	    || need_resched() || signal_pending(current)) {
 		vcpu->mode = OUTSIDE_GUEST_MODE;
-- 
1.7.1