Add NUMA topology support

libvirt has supported specification of a guest NUMA topology since
0.9.8. This functionality can be used for basic validation of some
NUMA-dependent features during development. Add basic configuration
support, by allowing the user to specify how many NUMA nodes the
instance may have.

The following options are added:

* numa_nodes - Defaults to none

For additional information on specifying NUMA nodes with Libvirt, see:

* https://libvirt.org/formatdomain.html#elementsCPU

README.md

@@ -237,6 +237,7 @@ end
 * `cpu_fallback` - Whether to allow libvirt to fall back to a CPU model close
   to the specified model if features in the guest CPU are not supported on the
   host. Defaults to 'allow' if not set. Allowed values: `allow`, `forbid`.
+* `numa_nodes` - Number of NUMA nodes on guest. Must be a factor of `cpu`.
 * `loader` - Sets path to custom UEFI loader.
 * `volume_cache` - Controls the cache mechanism. Possible values are "default",
   "none", "writethrough", "writeback", "directsync" and "unsafe". [See

lib/vagrant-libvirt/action/create_domain.rb

@@ -37,6 +37,7 @@ module VagrantPlugins
           @cpu_mode = config.cpu_mode
           @cpu_model = config.cpu_model
           @cpu_fallback = config.cpu_fallback
+          @numa_nodes = config.numa_nodes
           @loader = config.loader
           @machine_type = config.machine_type
           @machine_arch = config.machine_arch

lib/vagrant-libvirt/config.rb

@@ -62,6 +62,7 @@ module VagrantPlugins
       attr_accessor :cpu_model
       attr_accessor :cpu_fallback
       attr_accessor :cpu_features
+      attr_accessor :numa_nodes
       attr_accessor :loader
       attr_accessor :boot_order
       attr_accessor :machine_type
@@ -143,6 +144,7 @@ module VagrantPlugins
         @cpu_model         = UNSET_VALUE
         @cpu_fallback      = UNSET_VALUE
         @cpu_features      = UNSET_VALUE
+        @numa_nodes        = UNSET_VALUE
         @loader            = UNSET_VALUE
         @machine_type      = UNSET_VALUE
         @machine_arch      = UNSET_VALUE
@@ -232,6 +234,29 @@ module VagrantPlugins
         raise 'Only four cdroms may be attached at a time'
       end
 
+      def _generate_numa
+        if @cpus % @numa_nodes != 0
+          raise 'NUMA nodes must be a factor of CPUs'
+        end
+
+        numa = []
+
+        (1..@numa_nodes).each do |node|
+          numa_cpu_start = (@cpus / @numa_nodes) * (node - 1)
+          numa_cpu_end = (@cpus / @numa_nodes) * node - 1
+          numa_cpu = Array(numa_cpu_start..numa_cpu_end).join(',')
+          numa_mem = @memory / @numa_nodes
+
+          numa.push({
+            id: node,
+            cpu: numa_cpu,
+            mem: numa_mem
+          })
+        end
+
+        @numa_nodes = numa
+      end
+
       def cpu_feature(options={})
         if options[:name].nil? || options[:policy].nil?
           raise 'CPU Feature name AND policy must be specified'
@@ -457,6 +482,7 @@ module VagrantPlugins
         @cpu_model = 'qemu64' if @cpu_model == UNSET_VALUE
         @cpu_fallback = 'allow' if @cpu_fallback == UNSET_VALUE
         @cpu_features = [] if @cpu_features == UNSET_VALUE
+        @numa_nodes = _generate_numa() if @numa_nodes != UNSET_VALUE
         @loader = nil if @loader == UNSET_VALUE
         @machine_type = nil if @machine_type == UNSET_VALUE
         @machine_arch = nil if @machine_arch == UNSET_VALUE

lib/vagrant-libvirt/templates/domain.xml.erb

@@ -15,6 +15,14 @@
       <% @cpu_features.each do |cpu_feature| %>
         <feature name='<%= cpu_feature[:name] %>' policy='<%= cpu_feature[:policy] %>'/>
       <% end %>
+    <% else %>
+      <% if @numa_nodes %>
+        <numa>
+          <% @numa_nodes.each do |node| %>
+            <cell id='<%= node[:id] %>' cpus='<%= node[:cpu] %>' memory='<%= node[:mem] %>'/>
+          <% end %>
+        </numa>
+      <% end %>
     <% end %>
   </cpu>