x86, apicv: add virtual interrupt delivery support

Virtual interrupt delivery avoids KVM to inject vAPIC interrupts
manually, which is fully taken care of by the hardware. This needs
some special awareness into existing interrupr injection path:

- for pending interrupt, instead of direct injection, we may need
  update architecture specific indicators before resuming to guest.

- A pending interrupt, which is masked by ISR, should be also
  considered in above update action, since hardware will decide
  when to inject it at right time. Current has_interrupt and
  get_interrupt only returns a valid vector from injection p.o.v.

Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

4 files changed, 73 insertions, 0 deletions

diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index f3abbef..ce82b94 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -35,6 +35,7 @@
 #include <linux/hrtimer.h>
 #include <linux/io.h>
 #include <linux/slab.h>
+#include <linux/export.h>
 #include <asm/processor.h>
 #include <asm/page.h>
 #include <asm/current.h>
@@ -115,6 +116,42 @@ static void update_handled_vectors(struct kvm_ioapic *ioapic)
 	smp_wmb();
 }
 
+void kvm_ioapic_calculate_eoi_exitmap(struct kvm_vcpu *vcpu,
+					u64 *eoi_exit_bitmap)
+{
+	struct kvm_ioapic *ioapic = vcpu->kvm->arch.vioapic;
+	union kvm_ioapic_redirect_entry *e;
+	struct kvm_lapic_irq irqe;
+	int index;
+
+	spin_lock(&ioapic->lock);
+	/* traverse ioapic entry to set eoi exit bitmap*/
+	for (index = 0; index < IOAPIC_NUM_PINS; index++) {
+		e = &ioapic->redirtbl[index];
+		if (!e->fields.mask &&
+			(e->fields.trig_mode == IOAPIC_LEVEL_TRIG ||
+			 kvm_irq_has_notifier(ioapic->kvm, KVM_IRQCHIP_IOAPIC,
+				 index))) {
+			irqe.dest_id = e->fields.dest_id;
+			irqe.vector = e->fields.vector;
+			irqe.dest_mode = e->fields.dest_mode;
+			irqe.delivery_mode = e->fields.delivery_mode << 8;
+			kvm_calculate_eoi_exitmap(vcpu, &irqe, eoi_exit_bitmap);
+		}
+	}
+	spin_unlock(&ioapic->lock);
+}
+EXPORT_SYMBOL_GPL(kvm_ioapic_calculate_eoi_exitmap);
+
+void kvm_ioapic_make_eoibitmap_request(struct kvm *kvm)
+{
+	struct kvm_ioapic *ioapic = kvm->arch.vioapic;
+
+	if (!kvm_apic_vid_enabled(kvm) || !ioapic)
+		return;
+	kvm_make_update_eoibitmap_request(kvm);
+}
+
 static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
 {
 	unsigned index;
@@ -156,6 +193,7 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
 		if (e->fields.trig_mode == IOAPIC_LEVEL_TRIG
 		    && ioapic->irr & (1 << index))
 			ioapic_service(ioapic, index);
+		kvm_ioapic_make_eoibitmap_request(ioapic->kvm);
 		break;
 	}
 }
@@ -455,6 +493,7 @@ int kvm_set_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state)
 	spin_lock(&ioapic->lock);
 	memcpy(ioapic, state, sizeof(struct kvm_ioapic_state));
 	update_handled_vectors(ioapic);
+	kvm_ioapic_make_eoibitmap_request(kvm);
 	spin_unlock(&ioapic->lock);
 	return 0;
 }
diff --git a/virt/kvm/ioapic.h b/virt/kvm/ioapic.h
index a30abfe..0400a46 100644
--- a/virt/kvm/ioapic.h
+++ b/virt/kvm/ioapic.h
@@ -82,5 +82,9 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
 		struct kvm_lapic_irq *irq);
 int kvm_get_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state);
 int kvm_set_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state);
+void kvm_ioapic_make_eoibitmap_request(struct kvm *kvm);
+void kvm_ioapic_calculate_eoi_exitmap(struct kvm_vcpu *vcpu,
+					u64 *eoi_exit_bitmap);
+
 
 #endif
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 656fa45..ff6d40e 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -22,6 +22,7 @@
 
 #include <linux/kvm_host.h>
 #include <linux/slab.h>
+#include <linux/export.h>
 #include <trace/events/kvm.h>
 
 #include <asm/msidef.h>
@@ -237,6 +238,28 @@ int kvm_set_irq_inatomic(struct kvm *kvm, int irq_source_id, u32 irq, int level)
 	return ret;
 }
 
+bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin)
+{
+	struct kvm_irq_ack_notifier *kian;
+	struct hlist_node *n;
+	int gsi;
+
+	rcu_read_lock();
+	gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
+	if (gsi != -1)
+		hlist_for_each_entry_rcu(kian, n, &kvm->irq_ack_notifier_list,
+					 link)
+			if (kian->gsi == gsi) {
+				rcu_read_unlock();
+				return true;
+			}
+
+	rcu_read_unlock();
+
+	return false;
+}
+EXPORT_SYMBOL_GPL(kvm_irq_has_notifier);
+
 void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
 {
 	struct kvm_irq_ack_notifier *kian;
@@ -261,6 +284,7 @@ void kvm_register_irq_ack_notifier(struct kvm *kvm,
 	mutex_lock(&kvm->irq_lock);
 	hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list);
 	mutex_unlock(&kvm->irq_lock);
+	kvm_ioapic_make_eoibitmap_request(kvm);
 }
 
 void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
@@ -270,6 +294,7 @@ void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
 	hlist_del_init_rcu(&kian->link);
 	mutex_unlock(&kvm->irq_lock);
 	synchronize_rcu();
+	kvm_ioapic_make_eoibitmap_request(kvm);
 }
 
 int kvm_request_irq_source_id(struct kvm *kvm)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 3fec2cd..abc23e2 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -217,6 +217,11 @@ void kvm_make_mclock_inprogress_request(struct kvm *kvm)
 	make_all_cpus_request(kvm, KVM_REQ_MCLOCK_INPROGRESS);
 }
 
+void kvm_make_update_eoibitmap_request(struct kvm *kvm)
+{
+	make_all_cpus_request(kvm, KVM_REQ_EOIBITMAP);
+}
+
 int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
 {
 	struct page *page;