Implement EFI host creation

This implements EFI host creation by specifying the os_firmware
attribute to be efi. It's also possible to set the os_loader attribute
to secure (for UEFI secure boot) or stateless (for AMD SEV). Both secure
and stateless imply the os_firmware to be efi.

lib/fog/libvirt/models/compute/server.rb

@@ -13,7 +13,9 @@ class Server < Fog::Compute::Server
 
         attribute :cpus
         attribute :cputime
+        attribute :os_firmware
         attribute :os_type
+        attribute :os_loader
         attribute :memory_size
         attribute :max_memory_size
         attribute :name
@@ -281,10 +283,28 @@ def to_xml
               end
 
               xml.vcpu(cpus)
-              xml.os do
+
+              os_tags = {}
+
+              # Secure boot and stateless UEFI both imply an EFI firmware
+              if ["secure", "stateless"].include?(os_loader)
+                os_tags[:firmware] = "efi"
+              elsif os_firmware
+                os_tags[:firmware] = os_firmware
+              end
+
+              xml.os(**os_tags) do
                 type = xml.type(os_type, :arch => arch)
                 type[:machine] = "q35" if ["i686", "x86_64"].include?(arch)
 
+                # TODO: can you use both secure and stateless at the same time?
+                case attributes[:os_loader]
+                when "secure"
+                  xml.loader(:secure => "yes")
+                when "stateless"
+                  xml.loader(:stateless => "yes")
+                end
+
                 boot_order.each do |dev|
                   xml.boot(:dev => dev)
                 end

tests/libvirt/models/compute/server_tests.rb

@@ -30,6 +30,8 @@
       attributes = [ :id,
         :cpus,
         :cputime,
+        :os_firmware,
+        :os_loader,
         :os_type,
         :memory_size,
         :max_memory_size,
@@ -60,6 +62,7 @@
     end
     test('be a kind of Fog::Libvirt::Compute::Server') { server.kind_of? Fog::Libvirt::Compute::Server }
     tests("serializes to xml") do
+      test("without firmware") { server.to_xml.match?(%r{<os>}) }
       test("with memory") { server.to_xml.match?(%r{<memory>\d+</memory>}) }
       test("with disk of type file") do
         xml = server.to_xml
@@ -78,6 +81,27 @@
         xml.match?(/<disk type="block" device="disk">/) && xml.match?(%r{<source dev="/dev/sda"/>})
       end
       test("with q35 machine type on x86_64") { server.to_xml.match?(%r{<type arch="x86_64" machine="q35">hvm</type>}) }
+      test("with efi firmware") do
+        server = Fog::Libvirt::Compute::Server.new(
+          {
+            :os_firmware => 'efi',
+            :nics => [],
+            :volumes => [],
+          }
+        )
+        server.to_xml.match?(%r{<os firmware="efi">})
+      end
+      test("with secure boot") do
+        server = Fog::Libvirt::Compute::Server.new(
+          {
+            :os_loader => 'secure',
+            :nics => [],
+            :volumes => [],
+          }
+        )
+        xml = server.to_xml
+        xml.include?('<os firmware="efi">') && xml.include?('<loader secure="yes"/>')
+      end
     end
   end
 end