Add memory backing configuration

README.md

@@ -974,6 +974,24 @@ Vagrant.configure("2") do |config|
 end
 ```
 
+## Memory Backing
+
+You can specify memoryBacking options via `libvirt.memorybacking`. Available options are shown below. Full documentation is available at the [libvirt _memoryBacking_ section](https://libvirt.org/formatdomain.html#elementsMemoryBacking).
+
+NOTE: The hugepages `<page>` element is not yet supported
+
+```ruby
+Vagrant.configure("2") do |config|
+  config.vm.provider :libvirt do |libvirt|
+    libvirt.memorybacking :hugepages
+    libvirt.memorybacking :nosharepages
+    libvirt.memorybacking :locked
+    libvirt.memorybacking :source, :type => 'file'
+    libvirt.memorybacking :access, :mode => 'shared'
+    libvirt.memorybacking :allocation, :mode => 'immediate'
+  end
+end
+```
 ## USB device passthrough
 
 You can specify multiple USB devices to passthrough to the VM via

lib/vagrant-libvirt/action/create_domain.rb

@@ -46,6 +46,7 @@ module VagrantPlugins
           @disk_device = config.disk_device
           @nested = config.nested
           @memory_size = config.memory.to_i * 1024
+          @memory_backing = config.memory_backing
           @management_network_mac = config.management_network_mac
           @domain_volume_cache = config.volume_cache
           @kernel = config.kernel
@@ -182,6 +183,9 @@ module VagrantPlugins
             env[:ui].info(" -- Feature:           #{feature}")
           end
           env[:ui].info(" -- Memory:            #{@memory_size / 1024}M")
+          @memory_backing.each do |backing|
+            env[:ui].info(" -- Memory Backing:    #{backing[:name]}: #{backing[:config].map { |k,v| "#{k}='#{v}'"}.join(' ')}")
+          end
           env[:ui].info(" -- Management MAC:    #{@management_network_mac}")
           env[:ui].info(" -- Loader:            #{@loader}")
           if env[:machine].config.vm.box

lib/vagrant-libvirt/config.rb

@@ -58,6 +58,7 @@ module VagrantPlugins
       # Domain specific settings used while creating new domain.
       attr_accessor :uuid
       attr_accessor :memory
+      attr_accessor :memory_backing
       attr_accessor :channel
       attr_accessor :cpus
       attr_accessor :cpu_mode
@@ -164,6 +165,7 @@ module VagrantPlugins
         # Domain specific settings.
         @uuid              = UNSET_VALUE
         @memory            = UNSET_VALUE
+        @memory_backing    = UNSET_VALUE
         @cpus              = UNSET_VALUE
         @cpu_mode          = UNSET_VALUE
         @cpu_model         = UNSET_VALUE
@@ -313,6 +315,21 @@ module VagrantPlugins
                            policy: options[:policy])
       end
 
+      def memorybacking(option, config = {})
+        case option
+        when :source
+          raise 'Source type must be specified' if config[:type].nil?
+        when :access
+          raise 'Access mode must be specified' if config[:mode].nil?
+        when :allocation
+          raise 'Allocation mode must be specified' if config[:mode].nil?
+        end
+
+        @memory_backing = [] if @memory_backing == UNSET_VALUE
+        @memory_backing.push(name: option,
+                             config: config)
+      end
+
       def input(options = {})
         if options[:type].nil? || options[:bus].nil?
           raise 'Input type AND bus must be specified'
@@ -569,6 +586,7 @@ module VagrantPlugins
         # Domain specific settings.
         @uuid = '' if @uuid == UNSET_VALUE
         @memory = 512 if @memory == UNSET_VALUE
+        @memory_backing = [] if @memory_backing == UNSET_VALUE
         @cpus = 1 if @cpus == UNSET_VALUE
         @cpu_mode = 'host-model' if @cpu_mode == UNSET_VALUE
         @cpu_model = if (@cpu_model == UNSET_VALUE) && (@cpu_mode == 'custom')

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

@@ -25,6 +25,13 @@
     <% end %>
   </cpu>
 
+<% unless @memory_backing.empty? %>
+  <memoryBacking>
+  <% @memory_backing.each do |backing| %>
+    <<%= backing[:name] %> <%= backing[:config].map { |k,v| "#{k}='#{v}'"}.join(' ')  %>/>
+  <% end %>
+  </memoryBacking>
+<% end%>
 
   <os>
     <% if @machine_type %>