[PATCH 1/8] KVM: arm/arm64: vgic: Add LPI translation cache definition

[Marc Zyngier <marc.zyngier@arm.com>]

Add the basic data structure that expresses an MSI to LPI
translation as well as the allocation/release hooks.

THe size of the cache is arbitrarily defined as 4*nr_vcpus.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 include/kvm/arm_vgic.h        | 10 ++++++++++
 virt/kvm/arm/vgic/vgic-init.c | 34 ++++++++++++++++++++++++++++++++++
 virt/kvm/arm/vgic/vgic-its.c  |  2 ++
 virt/kvm/arm/vgic/vgic.h      |  3 +++
 4 files changed, 49 insertions(+)

diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index c36c86f1ec9a..5a0d6b07c5ef 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -173,6 +173,14 @@ struct vgic_io_device {
 	struct kvm_io_device dev;
 };
 
+struct vgic_translation_cache_entry {
+	struct list_head	entry;
+	phys_addr_t		db;
+	u32			devid;
+	u32			eventid;
+	struct vgic_irq		*irq;
+};
+
 struct vgic_its {
 	/* The base address of the ITS control register frame */
 	gpa_t			vgic_its_base;
@@ -260,6 +268,8 @@ struct vgic_dist {
 	struct list_head	lpi_list_head;
 	int			lpi_list_count;
 
+	struct list_head	lpi_translation_cache;
+
 	/* used by vgic-debug */
 	struct vgic_state_iter *iter;
 
diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index 3bdb31eaed64..25ae25694a28 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -64,6 +64,7 @@ void kvm_vgic_early_init(struct kvm *kvm)
 	struct vgic_dist *dist = &kvm->arch.vgic;
 
 	INIT_LIST_HEAD(&dist->lpi_list_head);
+	INIT_LIST_HEAD(&dist->lpi_translation_cache);
 	raw_spin_lock_init(&dist->lpi_list_lock);
 }
 
@@ -260,6 +261,27 @@ static void kvm_vgic_vcpu_enable(struct kvm_vcpu *vcpu)
 		vgic_v3_enable(vcpu);
 }
 
+void vgic_lpi_translation_cache_init(struct kvm *kvm)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	int i;
+
+	if (!list_empty(&dist->lpi_translation_cache))
+		return;
+
+	for (i = 0; i < LPI_CACHE_SIZE(kvm); i++) {
+		struct vgic_translation_cache_entry *cte;
+
+		/* An allocation failure is not fatal */
+		cte = kzalloc(sizeof(*cte), GFP_KERNEL);
+		if (WARN_ON(!cte))
+			break;
+
+		INIT_LIST_HEAD(&cte->entry);
+		list_add(&cte->entry, &dist->lpi_translation_cache);
+	}
+}
+
 /*
  * vgic_init: allocates and initializes dist and vcpu data structures
  * depending on two dimensioning parameters:
@@ -305,6 +327,7 @@ int vgic_init(struct kvm *kvm)
 	}
 
 	if (vgic_has_its(kvm)) {
+		vgic_lpi_translation_cache_init(kvm);
 		ret = vgic_v4_init(kvm);
 		if (ret)
 			goto out;
@@ -346,6 +369,17 @@ static void kvm_vgic_dist_destroy(struct kvm *kvm)
 		INIT_LIST_HEAD(&dist->rd_regions);
 	}
 
+	if (vgic_has_its(kvm)) {
+		struct vgic_translation_cache_entry *cte, *tmp;
+
+		list_for_each_entry_safe(cte, tmp,
+					 &dist->lpi_translation_cache, entry) {
+			list_del(&cte->entry);
+			kfree(cte);
+		}
+		INIT_LIST_HEAD(&dist->lpi_translation_cache);
+	}
+
 	if (vgic_supports_direct_msis(kvm))
 		vgic_v4_teardown(kvm);
 }
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 44ceaccb18cf..5758504fd934 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -1696,6 +1696,8 @@ static int vgic_its_create(struct kvm_device *dev, u32 type)
 			kfree(its);
 			return ret;
 		}
+
+		vgic_lpi_translation_cache_init(dev->kvm);
 	}
 
 	mutex_init(&its->its_lock);
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index abeeffabc456..a58e1b263dca 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -316,6 +316,9 @@ int vgic_copy_lpi_list(struct kvm *kvm, struct kvm_vcpu *vcpu, u32 **intid_ptr);
 int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its,
 			 u32 devid, u32 eventid, struct vgic_irq **irq);
 struct vgic_its *vgic_msi_to_its(struct kvm *kvm, struct kvm_msi *msi);
+void vgic_lpi_translation_cache_init(struct kvm *kvm);
+
+#define LPI_CACHE_SIZE(kvm)	(atomic_read(&(kvm)->online_vcpus) * 4)
 
 bool vgic_supports_direct_msis(struct kvm *kvm);
 int vgic_v4_init(struct kvm *kvm);
-- 
2.20.1