KVM: arm/arm64: vgic-new: vgic_init: implement vgic_init

This patch allocates and initializes the data structures used
to model the vgic distributor and virtual cpu interfaces. At that
stage the number of IRQs and number of virtual CPUs is frozen.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 217 insertions, 0 deletions

diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index 15d54284305b..bed3240bd634 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -22,6 +22,42 @@
 #include <asm/kvm_mmu.h>
 #include "vgic.h"
 
+/*
+ * Initialization rules: there are multiple stages to the vgic
+ * initialization, both for the distributor and the CPU interfaces.
+ *
+ * Distributor:
+ *
+ * - kvm_vgic_early_init(): initialization of static data that doesn't
+ *   depend on any sizing information or emulation type. No allocation
+ *   is allowed there.
+ *
+ * - vgic_init(): allocation and initialization of the generic data
+ *   structures that depend on sizing information (number of CPUs,
+ *   number of interrupts). Also initializes the vcpu specific data
+ *   structures. Can be executed lazily for GICv2.
+ *
+ * CPU Interface:
+ *
+ * - kvm_vgic_cpu_early_init(): initialization of static data that
+ *   doesn't depend on any sizing information or emulation type. No
+ *   allocation is allowed there.
+ */
+
+/* EARLY INIT */
+
+/*
+ * Those 2 functions should not be needed anymore but they
+ * still are called from arm.c
+ */
+void kvm_vgic_early_init(struct kvm *kvm)
+{
+}
+
+void kvm_vgic_vcpu_early_init(struct kvm_vcpu *vcpu)
+{
+}
+
 /* CREATION */
 
 /**
@@ -29,6 +65,8 @@
  * user space, either through the legacy KVM_CREATE_IRQCHIP ioctl (v2 only)
  * or through the generic KVM_CREATE_DEVICE API ioctl.
  * irqchip_in_kernel() tells you if this function succeeded or not.
+ * @kvm: kvm struct pointer
+ * @type: KVM_DEV_TYPE_ARM_VGIC_V[23]
  */
 int kvm_vgic_create(struct kvm *kvm, u32 type)
 {
@@ -106,6 +144,185 @@ out:
 	return ret;
 }
 
+/* INIT/DESTROY */
+
+/**
+ * kvm_vgic_dist_init: initialize the dist data structures
+ * @kvm: kvm struct pointer
+ * @nr_spis: number of spis, frozen by caller
+ */
+static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	struct kvm_vcpu *vcpu0 = kvm_get_vcpu(kvm, 0);
+	int i;
+
+	dist->spis = kcalloc(nr_spis, sizeof(struct vgic_irq), GFP_KERNEL);
+	if (!dist->spis)
+		return  -ENOMEM;
+
+	/*
+	 * In the following code we do not take the irq struct lock since
+	 * no other action on irq structs can happen while the VGIC is
+	 * not initialized yet:
+	 * If someone wants to inject an interrupt or does a MMIO access, we
+	 * require prior initialization in case of a virtual GICv3 or trigger
+	 * initialization when using a virtual GICv2.
+	 */
+	for (i = 0; i < nr_spis; i++) {
+		struct vgic_irq *irq = &dist->spis[i];
+
+		irq->intid = i + VGIC_NR_PRIVATE_IRQS;
+		INIT_LIST_HEAD(&irq->ap_list);
+		spin_lock_init(&irq->irq_lock);
+		irq->vcpu = NULL;
+		irq->target_vcpu = vcpu0;
+		if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
+			irq->targets = 0;
+		else
+			irq->mpidr = 0;
+	}
+	return 0;
+}
+
+/**
+ * kvm_vgic_vcpu_init: initialize the vcpu data structures and
+ * enable the VCPU interface
+ * @vcpu: the VCPU which's VGIC should be initialized
+ */
+static void kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+	int i;
+
+	INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
+	spin_lock_init(&vgic_cpu->ap_list_lock);
+
+	/*
+	 * Enable and configure all SGIs to be edge-triggered and
+	 * configure all PPIs as level-triggered.
+	 */
+	for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
+		struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
+
+		INIT_LIST_HEAD(&irq->ap_list);
+		spin_lock_init(&irq->irq_lock);
+		irq->intid = i;
+		irq->vcpu = NULL;
+		irq->target_vcpu = vcpu;
+		irq->targets = 1U << vcpu->vcpu_id;
+		if (vgic_irq_is_sgi(i)) {
+			/* SGIs */
+			irq->enabled = 1;
+			irq->config = VGIC_CONFIG_EDGE;
+		} else {
+			/* PPIs */
+			irq->config = VGIC_CONFIG_LEVEL;
+		}
+	}
+	if (kvm_vgic_global_state.type == VGIC_V2)
+		vgic_v2_enable(vcpu);
+	else
+		vgic_v3_enable(vcpu);
+}
+
+/*
+ * vgic_init: allocates and initializes dist and vcpu data structures
+ * depending on two dimensioning parameters:
+ * - the number of spis
+ * - the number of vcpus
+ * The function is generally called when nr_spis has been explicitly set
+ * by the guest through the KVM DEVICE API. If not nr_spis is set to 256.
+ * vgic_initialized() returns true when this function has succeeded.
+ * Must be called with kvm->lock held!
+ */
+int vgic_init(struct kvm *kvm)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	struct kvm_vcpu *vcpu;
+	int ret = 0, i;
+
+	if (vgic_initialized(kvm))
+		return 0;
+
+	/* freeze the number of spis */
+	if (!dist->nr_spis)
+		dist->nr_spis = VGIC_NR_IRQS_LEGACY - VGIC_NR_PRIVATE_IRQS;
+
+	ret = kvm_vgic_dist_init(kvm, dist->nr_spis);
+	if (ret)
+		goto out;
+
+	kvm_for_each_vcpu(i, vcpu, kvm)
+		kvm_vgic_vcpu_init(vcpu);
+
+	dist->initialized = true;
+out:
+	return ret;
+}
+
+static void kvm_vgic_dist_destroy(struct kvm *kvm)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+
+	mutex_lock(&kvm->lock);
+
+	dist->ready = false;
+	dist->initialized = false;
+
+	kfree(dist->spis);
+	kfree(dist->redist_iodevs);
+	dist->nr_spis = 0;
+
+	mutex_unlock(&kvm->lock);
+}
+
+void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+
+	INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
+}
+
+void kvm_vgic_destroy(struct kvm *kvm)
+{
+	struct kvm_vcpu *vcpu;
+	int i;
+
+	kvm_vgic_dist_destroy(kvm);
+
+	kvm_for_each_vcpu(i, vcpu, kvm)
+		kvm_vgic_vcpu_destroy(vcpu);
+}
+
+/**
+ * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest
+ * is a GICv2. A GICv3 must be explicitly initialized by the guest using the
+ * KVM_DEV_ARM_VGIC_GRP_CTRL KVM_DEVICE group.
+ * @kvm: kvm struct pointer
+ */
+int vgic_lazy_init(struct kvm *kvm)
+{
+	int ret = 0;
+
+	if (unlikely(!vgic_initialized(kvm))) {
+		/*
+		 * We only provide the automatic initialization of the VGIC
+		 * for the legacy case of a GICv2. Any other type must
+		 * be explicitly initialized once setup with the respective
+		 * KVM device call.
+		 */
+		if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2)
+			return -EBUSY;
+
+		mutex_lock(&kvm->lock);
+		ret = vgic_init(kvm);
+		mutex_unlock(&kvm->lock);
+	}
+
+	return ret;
+}
+
 /* GENERIC PROBE */
 
 static void vgic_init_maintenance_interrupt(void *info)