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

This patch implements the vgic_creation function which is
called on CREATE_IRQCHIP VM IOCTL (v2 only) or KVM_CREATE_DEVICE

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, 84 insertions, 0 deletions

diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index 4523beb029f3..15d54284305b 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -22,6 +22,90 @@
 #include <asm/kvm_mmu.h>
 #include "vgic.h"
 
+/* CREATION */
+
+/**
+ * kvm_vgic_create: triggered by the instantiation of the VGIC device by
+ * 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.
+ */
+int kvm_vgic_create(struct kvm *kvm, u32 type)
+{
+        int i, vcpu_lock_idx = -1, ret;
+        struct kvm_vcpu *vcpu;
+
+        mutex_lock(&kvm->lock);
+
+        if (irqchip_in_kernel(kvm)) {
+                ret = -EEXIST;
+                goto out;
+        }
+
+        /*
+         * This function is also called by the KVM_CREATE_IRQCHIP handler,
+         * which had no chance yet to check the availability of the GICv2
+         * emulation. So check this here again. KVM_CREATE_DEVICE does
+         * the proper checks already.
+         */
+        if (type == KVM_DEV_TYPE_ARM_VGIC_V2 &&
+                !kvm_vgic_global_state.can_emulate_gicv2) {
+                ret = -ENODEV;
+                goto out;
+        }
+
+        /*
+         * Any time a vcpu is run, vcpu_load is called which tries to grab the
+         * vcpu->mutex.  By grabbing the vcpu->mutex of all VCPUs we ensure
+         * that no other VCPUs are run while we create the vgic.
+         */
+        ret = -EBUSY;
+        kvm_for_each_vcpu(i, vcpu, kvm) {
+                if (!mutex_trylock(&vcpu->mutex))
+                        goto out_unlock;
+                vcpu_lock_idx = i;
+        }
+
+        kvm_for_each_vcpu(i, vcpu, kvm) {
+                if (vcpu->arch.has_run_once)
+                        goto out_unlock;
+        }
+        ret = 0;
+
+        if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
+                kvm->arch.max_vcpus = VGIC_V2_MAX_CPUS;
+        else
+                kvm->arch.max_vcpus = VGIC_V3_MAX_CPUS;
+
+        if (atomic_read(&kvm->online_vcpus) > kvm->arch.max_vcpus) {
+                ret = -E2BIG;
+                goto out_unlock;
+        }
+
+        kvm->arch.vgic.in_kernel = true;
+        kvm->arch.vgic.vgic_model = type;
+
+        /*
+         * kvm_vgic_global_state.vctrl_base is set on vgic probe (kvm_arch_init)
+         * it is stored in distributor struct for asm save/restore purpose
+         */
+        kvm->arch.vgic.vctrl_base = kvm_vgic_global_state.vctrl_base;
+
+        kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
+        kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
+        kvm->arch.vgic.vgic_redist_base = VGIC_ADDR_UNDEF;
+
+out_unlock:
+        for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
+                vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
+                mutex_unlock(&vcpu->mutex);
+        }
+
+out:
+        mutex_unlock(&kvm->lock);
+        return ret;
+}
+
 /* GENERIC PROBE */
 
 static void vgic_init_maintenance_interrupt(void *info)