[PATCH v4 08/12] KVM: arm64: connect LPIs to the VGIC emulation

[Andre Przywara <andre.przywara@arm.com>]

LPIs are dynamically created (mapped) at guest runtime and their
actual numbers can be quite high, but is mostly assigned using a very
sparse allocation scheme. So arrays are not an ideal data structure
to hold the information. We use our equivalent of the "Interrupt
Translation Table Entry" (ITTE) to hold the vgic_irq struct for a
virtual LPI embedded in in the ITTE.
Connect the VGIC core code via an accessor function to help it get the
struct vgic_irq for a certain LPI.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 virt/kvm/arm/vgic/its-emul.c | 29 +++++++++++++++++++++++++++++
 virt/kvm/arm/vgic/vgic.h     |  8 +++++++-
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/arm/vgic/its-emul.c b/virt/kvm/arm/vgic/its-emul.c
index c0334ff..1188e9a 100644
--- a/virt/kvm/arm/vgic/its-emul.c
+++ b/virt/kvm/arm/vgic/its-emul.c
@@ -55,11 +55,29 @@ struct its_collection {
 struct its_itte {
 	struct list_head itte_list;
 
+	struct vgic_irq irq;
 	struct its_collection *collection;
 	u32 lpi;
 	u32 event_id;
 };
 
+/* To be used as an iterator this macro misses the enclosing parentheses */
+#define for_each_lpi(dev, itte, kvm) \
+	list_for_each_entry(dev, &(kvm)->arch.vgic.its.device_list, dev_list) \
+		list_for_each_entry(itte, &(dev)->itt, itte_list)
+
+static struct its_itte *find_itte_by_lpi(struct kvm *kvm, int lpi)
+{
+	struct its_device *device;
+	struct its_itte *itte;
+
+	for_each_lpi(device, itte, kvm) {
+		if (itte->lpi == lpi)
+			return itte;
+	}
+	return NULL;
+}
+
 #define BASER_BASE_ADDRESS(x) ((x) & 0xfffffffff000ULL)
 
 static int vgic_mmio_read_its_ctlr(struct kvm_vcpu *vcpu,
@@ -166,6 +184,17 @@ static int vgic_mmio_read_its_idregs(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
+struct vgic_irq *vgic_its_get_lpi(struct kvm *kvm, u32 intid)
+{
+	struct its_itte *itte;
+
+	itte = find_itte_by_lpi(kvm, intid);
+	if (!itte)
+		return NULL;
+
+	return &itte->irq;
+}
+
 static void its_free_itte(struct its_itte *itte)
 {
 	list_del(&itte->itte_list);
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index 08f97d1..160c511 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -63,6 +63,7 @@ int vgic_register_redist_regions(struct kvm *kvm, gpa_t dist_base_address);
 
 int vits_init(struct kvm *kvm);
 void vgic_enable_lpis(struct kvm_vcpu *vcpu);
+struct vgic_irq *vgic_its_get_lpi(struct kvm *kvm, u32 intid);
 void vits_destroy(struct kvm *kvm);
 #else
 static inline void vgic_v3_irq_change_affinity(struct kvm *kvm, u32 intid,
@@ -129,7 +130,7 @@ static inline int vgic_register_redist_regions(struct kvm *kvm,
 	return -ENODEV;
 }
 
-int vits_init(struct kvm *kvm)
+static inline int vits_init(struct kvm *kvm)
 {
 	return 0;
 }
@@ -139,6 +140,11 @@ static inline void vgic_enable_lpis(struct kvm_vcpu *vcpu)
 	return;
 }
 
+static inline struct vgic_irq *vgic_its_get_lpi(struct kvm *kvm, u32 intid)
+{
+	return NULL;
+}
+
 static inline void vits_destroy(struct kvm *kvm)
 {
 	return;
-- 
2.7.3