From 717f87d86770e6290338c2e05e7aaca145b442a2 Mon Sep 17 00:00:00 2001
From: mtosatti@redhat.com <mtosatti@redhat.com>
Date: Tue, 14 Apr 2009 14:47:13 -0300
Subject: [PATCH 2/6] KVM: Interrupt mask notifiers for ioapic

commit d4f36909f8607e0d64633d23cde401520cc9b782
Author: Avi Kivity <avi@redhat.com>
Date:   Sun Jan 4 17:10:50 2009 +0200

    KVM: Interrupt mask notifiers for ioapic

    Allow clients to request notifications when the guest masks or unmasks a
    particular irq line.  This complements irq ack notifications, as the guest
    will not ack an irq line that is masked.

    Currently implemented for the ioapic only.

    Signed-off-by: Avi Kivity <avi@redhat.com>
    (cherry picked from commit 75858a84a6207f5e60196f6bbd18fde4250e5759)

Message-Id: <20090414174837.785519317@amt.cnet>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com
Bugzilla: 500263
RH-Upstream-status: applied(kvm/master)
Acked-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Zachary Amsden <zamsden@redhat.com>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
---
 include/linux/kvm_host.h |   17 +++++++++++++++++
 virt/kvm/ioapic.c        |    6 ++++++
 virt/kvm/irq_comm.c      |   24 ++++++++++++++++++++++++
 virt/kvm/kvm_main.c      |    3 +++
 4 files changed, 50 insertions(+), 0 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 11467dc..0ef30ff 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -127,6 +127,10 @@ struct kvm {
 	struct kvm_coalesced_mmio_ring *coalesced_mmio_ring;
 #endif
 
+#ifdef CONFIG_HAVE_KVM_IRQCHIP
+	struct hlist_head mask_notifier_list;
+#endif
+
 #ifdef KVM_ARCH_WANT_MMU_NOTIFIER
 	struct mmu_notifier mmu_notifier;
 	unsigned long mmu_notifier_seq;
@@ -322,6 +326,19 @@ struct kvm_assigned_dev_kernel {
 	struct pci_dev *dev;
 	struct kvm *kvm;
 };
+
+struct kvm_irq_mask_notifier {
+	void (*func)(struct kvm_irq_mask_notifier *kimn, bool masked);
+	int irq;
+	struct hlist_node link;
+};
+
+void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
+				    struct kvm_irq_mask_notifier *kimn);
+void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
+				      struct kvm_irq_mask_notifier *kimn);
+void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask);
+
 int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level);
 void kvm_notify_acked_irq(struct kvm *kvm, unsigned gsi);
 void kvm_register_irq_ack_notifier(struct kvm *kvm,
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 2948b72..e38eb9c 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -104,6 +104,7 @@ static int ioapic_service(struct kvm_ioapic *ioapic, unsigned int idx)
 static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
 {
 	unsigned index;
+	bool mask_before, mask_after;
 
 	switch (ioapic->ioregsel) {
 	case IOAPIC_REG_VERSION:
@@ -123,6 +124,7 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
 		ioapic_debug("change redir index %x val %x\n", index, val);
 		if (index >= IOAPIC_NUM_PINS)
 			return;
+		mask_before = ioapic->redirtbl[index].fields.mask;
 		if (ioapic->ioregsel & 1) {
 			ioapic->redirtbl[index].bits &= 0xffffffff;
 			ioapic->redirtbl[index].bits |= (u64) val << 32;
@@ -131,6 +133,9 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
 			ioapic->redirtbl[index].bits |= (u32) val;
 			ioapic->redirtbl[index].fields.remote_irr = 0;
 		}
+		mask_after = ioapic->redirtbl[index].fields.mask;
+		if (mask_before != mask_after)
+			kvm_fire_mask_notifiers(ioapic->kvm, index, mask_after);
 		if (ioapic->irr & (1 << index))
 			ioapic_service(ioapic, index);
 		break;
@@ -435,3 +440,4 @@ int kvm_ioapic_init(struct kvm *kvm)
 	kvm_io_bus_register_dev(&kvm->mmio_bus, &ioapic->dev);
 	return 0;
 }
+
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index a910e6e..0883b56 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -110,3 +110,27 @@ void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id)
 		clear_bit(irq_source_id, &kvm->arch.irq_states[i]);
 	clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap);
 }
+
+void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
+				    struct kvm_irq_mask_notifier *kimn)
+{
+	kimn->irq = irq;
+	hlist_add_head(&kimn->link, &kvm->mask_notifier_list);
+}
+
+void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
+				      struct kvm_irq_mask_notifier *kimn)
+{
+	hlist_del(&kimn->link);
+}
+
+void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask)
+{
+	struct kvm_irq_mask_notifier *kimn;
+	struct hlist_node *n;
+
+	hlist_for_each_entry(kimn, n, &kvm->mask_notifier_list, link)
+		if (kimn->irq == irq)
+			kimn->func(kimn, mask);
+}
+
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 247b8f8..b24aa5e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -822,6 +822,9 @@ static struct kvm *kvm_create_vm(void)
 
 	if (IS_ERR(kvm))
 		goto out;
+#ifdef CONFIG_HAVE_KVM_IRQCHIP
+	INIT_HLIST_HEAD(&kvm->mask_notifier_list);
+#endif
 
 #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
 	page = alloc_page(GFP_KERNEL | __GFP_ZERO);
-- 
1.6.3.rc4.29.g8146