qemu: support automatic VM managed save in system daemon

Currently automatic VM managed save is only performed in session
daemons, on desktop session close, or host OS shutdown request.

With this change it is possible to control shutdown behaviour for
all daemons. A recommended setup might be:

  auto_shutdown_try_save = "persistent"
  auto_shutdown_try_shutdown = "all"
  auto_shutdown_poweroff = "all"

Each setting accepts 'none', 'persistent', 'transient', and 'all'
to control what types of guest it applies to.

For historical compatibility, for the system daemon, the settings
currently default to:

  auto_shutdown_try_save = "none"
  auto_shutdown_try_shutdown = "none"
  auto_shutdown_poweroff = "none"

while for the session daemon they currently default to

  auto_shutdown_try_save = "persistent"
  auto_shutdown_try_shutdown = "none"
  auto_shutdown_poweroff = "none"

The system daemon settings should NOT be enabled if the traditional
libvirt-guests.service is already enabled.

Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

src/qemu/libvirtd_qemu.aug

@@ -103,6 +103,9 @@ module Libvirtd_qemu =
                  | bool_entry "auto_dump_bypass_cache"
                  | bool_entry "auto_start_bypass_cache"
                  | int_entry "auto_start_delay"
+                 | str_entry "auto_shutdown_try_save"
+                 | str_entry "auto_shutdown_try_shutdown"
+                 | str_entry "auto_shutdown_poweroff"
 
    let process_entry = str_entry "hugetlbfs_mount"
                  | str_entry "bridge_helper"

src/qemu/qemu.conf.in

@@ -664,6 +664,48 @@
 #
 #auto_start_delay = 0
 
+# The settings for auto shutdown actions accept one of
+# four possible options:
+#
+# * "none" - do not try to save any running VMs
+# * "persistent" - only try to save persistent running VMs
+# * "transient" - only try to save transient running VMs
+# * "all" - try to save all running VMs
+
+# Whether to perform managed save of running VMs if a host OS
+# shutdown is requested (system/session daemons), or the desktop
+# session terminates (session daemon only).
+#
+# Defaults to "persistent" for session daemons and "none"
+# for system daemons. The values "all" and "transient" are
+# not permitted for this setting, since managed save is not
+# implemented for transient VMs.
+#
+# If 'libvirt-guests.service' is enabled, then this must be
+# set to 'none' for system daemons to avoid dueling actions
+#auto_shutdown_try_save = "persistent"
+
+# As above, but with a graceful shutdown action instead of
+# managed save. If managed save is enabled, shutdown will
+# be tried only on failure to perform managed save.
+#
+# Defaults to "none"
+#
+# If 'libvirt-guests.service' is enabled, then this must be
+# set to 'none' for system daemons to avoid dueling actions
+#auto_shutdown_try_shutdown = "none"
+
+# As above, but with a forced poweroff instead of managed
+# save. If managed save or graceful shutdown are enabled,
+# forced poweroff will be tried only on failure of the
+# other options.
+#
+# Defaults to "none"
+#
+# If 'libvirt-guests.service' is enabled, then this must be
+# set to 'none' for system daemons to avoid dueling actions
+#auto_shutdown_poweroff = "none"
+
 # If provided by the host and a hugetlbfs mount point is configured,
 # a guest may request huge page backing.  When this mount point is
 # unspecified here, determination of a host mount point in /proc/mounts

src/qemu/qemu_conf.c

@@ -314,6 +314,21 @@ virQEMUDriverConfig *virQEMUDriverConfigNew(bool privileged,
     cfg->dumpGuestCore = true;
 #endif
 
+    if (privileged) {
+        /*
+         * Defer to libvirt-guests.service.
+         *
+         * XXX, or query if libvirt-guests.service is enabled perhaps ?
+         */
+        cfg->autoShutdownTrySave = VIR_DOMAIN_DRIVER_AUTO_SHUTDOWN_SCOPE_NONE;
+        cfg->autoShutdownTryShutdown = VIR_DOMAIN_DRIVER_AUTO_SHUTDOWN_SCOPE_NONE;
+        cfg->autoShutdownPoweroff = VIR_DOMAIN_DRIVER_AUTO_SHUTDOWN_SCOPE_NONE;
+    } else {
+        cfg->autoShutdownTrySave = VIR_DOMAIN_DRIVER_AUTO_SHUTDOWN_SCOPE_PERSISTENT;
+        cfg->autoShutdownTryShutdown = VIR_DOMAIN_DRIVER_AUTO_SHUTDOWN_SCOPE_NONE;
+        cfg->autoShutdownPoweroff = VIR_DOMAIN_DRIVER_AUTO_SHUTDOWN_SCOPE_NONE;
+    }
+
     return g_steal_pointer(&cfg);
 }
 
@@ -659,6 +674,10 @@ virQEMUDriverConfigLoadSaveEntry(virQEMUDriverConfig *cfg,
     g_autofree char *savestr = NULL;
     g_autofree char *dumpstr = NULL;
     g_autofree char *snapstr = NULL;
+    g_autofree char *autoShutdownTrySave = NULL;
+    g_autofree char *autoShutdownTryShutdown = NULL;
+    g_autofree char *autoShutdownPoweroff = NULL;
+    int autoShutdownVal;
 
     if (virConfGetValueString(conf, "save_image_format", &savestr) < 0)
         return -1;
@@ -695,6 +714,54 @@ virQEMUDriverConfigLoadSaveEntry(virQEMUDriverConfig *cfg,
         return -1;
     if (virConfGetValueUInt(conf, "auto_start_delay", &cfg->autoStartDelayMS) < 0)
         return -1;
+    if (virConfGetValueString(conf, "auto_shutdown_try_save", &autoShutdownTrySave) < 0)
+        return -1;
+
+    if (autoShutdownTrySave != NULL) {
+        if ((autoShutdownVal =
+             virDomainDriverAutoShutdownScopeTypeFromString(autoShutdownTrySave)) < 0) {
+            virReportError(VIR_ERR_INVALID_ARG,
+                           _("unknown auto_shutdown_try_save '%1$s'"),
+                           autoShutdownTrySave);
+            return -1;
+        }
+        cfg->autoShutdownTrySave = autoShutdownVal;
+    }
+
+    if (cfg->autoShutdownTrySave == VIR_DOMAIN_DRIVER_AUTO_SHUTDOWN_SCOPE_ALL ||
+        cfg->autoShutdownTrySave == VIR_DOMAIN_DRIVER_AUTO_SHUTDOWN_SCOPE_TRANSIENT) {
+        virReportError(VIR_ERR_INVALID_ARG, "%s",
+                       _("managed save cannot be requested for transient domains"));
+        return -1;
+    }
+
+    if (virConfGetValueString(conf, "auto_shutdown_try_shutdown", &autoShutdownTryShutdown) < 0)
+        return -1;
+
+    if (autoShutdownTryShutdown != NULL) {
+        if ((autoShutdownVal =
+             virDomainDriverAutoShutdownScopeTypeFromString(autoShutdownTryShutdown)) < 0) {
+            virReportError(VIR_ERR_INVALID_ARG,
+                           _("unknown auto_shutdown_try_shutdown '%1$s'"),
+                           autoShutdownTryShutdown);
+            return -1;
+        }
+        cfg->autoShutdownTryShutdown = autoShutdownVal;
+    }
+
+    if (virConfGetValueString(conf, "auto_shutdown_poweroff", &autoShutdownPoweroff) < 0)
+        return -1;
+
+    if (autoShutdownPoweroff != NULL) {
+        if ((autoShutdownVal =
+             virDomainDriverAutoShutdownScopeTypeFromString(autoShutdownPoweroff)) < 0) {
+            virReportError(VIR_ERR_INVALID_ARG,
+                           _("unknown auto_shutdown_poweroff '%1$s'"),
+                           autoShutdownPoweroff);
+            return -1;
+        }
+        cfg->autoShutdownPoweroff = autoShutdownVal;
+    }
 
     return 0;
 }

src/qemu/qemu_conf.h

@@ -43,6 +43,7 @@
 #include "virfilecache.h"
 #include "virfirmware.h"
 #include "virinhibitor.h"
+#include "domain_driver.h"
 
 #define QEMU_DRIVER_NAME "QEMU"
 
@@ -211,6 +212,9 @@ struct _virQEMUDriverConfig {
     bool autoDumpBypassCache;
     bool autoStartBypassCache;
     unsigned int autoStartDelayMS;
+    virDomainDriverAutoShutdownScope autoShutdownTrySave;
+    virDomainDriverAutoShutdownScope autoShutdownTryShutdown;
+    virDomainDriverAutoShutdownScope autoShutdownPoweroff;
 
     char *lockManagerName;
 

src/qemu/qemu_driver.c

@@ -966,13 +966,12 @@ qemuStateStop(void)
     g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(qemu_driver);
     virDomainDriverAutoShutdownConfig ascfg = {
         .uri = cfg->uri,
-        .trySave = VIR_DOMAIN_DRIVER_AUTO_SHUTDOWN_SCOPE_PERSISTENT,
-        .tryShutdown =  VIR_DOMAIN_DRIVER_AUTO_SHUTDOWN_SCOPE_NONE,
-        .poweroff = VIR_DOMAIN_DRIVER_AUTO_SHUTDOWN_SCOPE_NONE
+        .trySave = cfg->autoShutdownTrySave,
+        .tryShutdown = cfg->autoShutdownTryShutdown,
+        .poweroff = cfg->autoShutdownPoweroff,
     };
 
-    if (!qemu_driver->privileged)
-        virDomainDriverAutoShutdown(&ascfg);
+    virDomainDriverAutoShutdown(&ascfg);
 
     return 0;
 }

src/qemu/test_libvirtd_qemu.aug.in

@@ -80,6 +80,9 @@ module Test_libvirtd_qemu =
 { "auto_dump_bypass_cache" = "0" }
 { "auto_start_bypass_cache" = "0" }
 { "auto_start_delay" = "0" }
+{ "auto_shutdown_try_save" = "persistent" }
+{ "auto_shutdown_try_shutdown" = "none" }
+{ "auto_shutdown_poweroff" = "none" }
 { "hugetlbfs_mount" = "/dev/hugepages" }
 { "bridge_helper" = "qemu-bridge-helper" }
 { "set_process_name" = "1" }