qemu-ga: add guest-suspend-ram

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

qapi-schema-guest.json

@@ -319,3 +319,31 @@
 # Since: 1.1
 ##
 { 'command': 'guest-suspend-disk' }
+
+##
+# @guest-suspend-ram
+#
+# Suspend guest to ram.
+#
+# This command tries to execute the scripts provided by the pm-utils package.
+# If it's not available, the suspend operation will be performed by manually
+# writing to a sysfs file.
+#
+# For the best results it's strongly recommended to have the pm-utils
+# package installed in the guest.
+#
+# IMPORTANT: guest-suspend-ram requires QEMU to support the 'system_wakeup'
+# command.  Thus, it's *required* to query QEMU for the presence of the
+# 'system_wakeup' command before issuing guest-suspend-ram.
+#
+# Returns: nothing on success
+#          If suspend to ram is not supported, Unsupported
+#
+# Notes: o This is an asynchronous request. There's no guarantee a response
+#          will be sent
+#        o It's strongly recommended to issue the guest-sync command before
+#          sending commands when the guest resumes
+#
+# Since: 1.1
+##
+{ 'command': 'guest-suspend-ram' }

qga/commands-posix.c

@@ -705,6 +705,16 @@ void qmp_guest_suspend_disk(Error **err)
     guest_suspend("pm-hibernate", "disk", err);
 }
 
+void qmp_guest_suspend_ram(Error **err)
+{
+    bios_supports_mode("pm-is-supported", "--suspend", "mem", err);
+    if (error_is_set(err)) {
+        return;
+    }
+
+    guest_suspend("pm-suspend", "mem", err);
+}
+
 /* register init/cleanup routines for stateful command groups */
 void ga_command_state_init(GAState *s, GACommandState *cs)
 {

qga/commands-win32.c

@@ -129,6 +129,11 @@ void qmp_guest_suspend_disk(Error **err)
     error_set(err, QERR_UNSUPPORTED);
 }
 
+void qmp_guest_suspend_ram(Error **err)
+{
+    error_set(err, QERR_UNSUPPORTED);
+}
+
 /* register init/cleanup routines for stateful command groups */
 void ga_command_state_init(GAState *s, GACommandState *cs)
 {