arm/arm64: KVM: make the maximum number of vCPUs a per-VM value
Currently the maximum number of vCPUs supported is a global value
limited by the used GIC model. GICv3 will lift this limit, but we
still need to observe it for guests using GICv2.
So the maximum number of vCPUs is per-VM value, depending on the
GIC model the guest uses.
Store and check the value in struct kvm_arch, but keep it down to
8 for now.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 1c3b75e..2126bf5 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1878,6 +1878,17 @@
return 0;
}
+/**
+ * kvm_vgic_get_max_vcpus - Get the maximum number of VCPUs allowed by HW
+ *
+ * The host's GIC naturally limits the maximum amount of VCPUs a guest
+ * can use.
+ */
+int kvm_vgic_get_max_vcpus(void)
+{
+ return vgic->max_gic_vcpus;
+}
+
void kvm_vgic_destroy(struct kvm *kvm)
{
struct vgic_dist *dist = &kvm->arch.vgic;
@@ -2072,6 +2083,8 @@
dist->vm_ops.add_sgi_source = vgic_v2_add_sgi_source;
dist->vm_ops.init_model = vgic_v2_init_model;
dist->vm_ops.map_resources = vgic_v2_map_resources;
+
+ kvm->arch.max_vcpus = VGIC_V2_MAX_CPUS;
}
static int init_vgic_model(struct kvm *kvm, int type)
@@ -2084,6 +2097,9 @@
return -ENODEV;
}
+ if (atomic_read(&kvm->online_vcpus) > kvm->arch.max_vcpus)
+ return -E2BIG;
+
return 0;
}