qemu: add dbus-vmstate

Add dbusVMStates to keep a list of dbus-vmstate objects needed for
migration. They are populated on the command line during start or
qemuDBusVMStateAdd/Remove() will hotplug them as needed.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

src/qemu/Makefile.inc.am

@@ -13,6 +13,8 @@ QEMU_DRIVER_SOURCES = \
 	qemu/qemu_capabilities.h \
 	qemu/qemu_command.c \
 	qemu/qemu_command.h \
+	qemu/qemu_dbus.c \
+	qemu/qemu_dbus.h \
 	qemu/qemu_domain.c \
 	qemu/qemu_domain.h \
 	qemu/qemu_domain_address.c \

src/qemu/qemu_alias.c

@@ -841,3 +841,20 @@ qemuDomainGetUnmanagedPRAlias(const char *parentalias)
 
     return ret;
 }
+
+char *
+qemuAliasDBusVMStateFromId(const char *id)
+{
+    char *ret;
+    size_t i;
+
+    if (virAsprintf(&ret, "dbus-vms-%s", id) < 0)
+        return NULL;
+
+    for (i = 0; ret[i]; i++) {
+        if (ret[i] == ':')
+            ret[i] = '_';
+    }
+
+    return ret;
+}

src/qemu/qemu_alias.h

@@ -95,3 +95,6 @@ char *qemuAliasChardevFromDevAlias(const char *devAlias)
 const char *qemuDomainGetManagedPRAlias(void);
 
 char *qemuDomainGetUnmanagedPRAlias(const char *parentalias);
+
+char *qemuAliasDBusVMStateFromId(const char *id)
+    ATTRIBUTE_NONNULL(1);

src/qemu/qemu_command.c

@@ -27,6 +27,7 @@
 #include "qemu_interface.h"
 #include "qemu_alias.h"
 #include "qemu_security.h"
+#include "qemu_dbus.h"
 #include "qemu_block.h"
 #include "cpu/cpu.h"
 #include "dirname.h"
@@ -9983,6 +9984,85 @@ qemuBuildManagedPRCommandLine(virCommandPtr cmd,
 }
 
 
+static virJSONValuePtr
+qemuBuildDBusVMStateInfoPropsInternal(const char *alias,
+                                      const char *addr)
+{
+    virJSONValuePtr ret = NULL;
+
+    if (qemuMonitorCreateObjectProps(&ret,
+                                     "dbus-vmstate", alias,
+                                     "s:addr", addr, NULL) < 0)
+        return NULL;
+
+    return ret;
+}
+
+
+virJSONValuePtr
+qemuBuildDBusVMStateInfoProps(const char *id,
+                              const char *addr)
+{
+    VIR_AUTOFREE(char *) alias = qemuAliasDBusVMStateFromId(id);
+
+    if (!alias)
+        return NULL;
+
+    return qemuBuildDBusVMStateInfoPropsInternal(alias, addr);
+}
+
+
+typedef struct qemuBuildDBusVMStateCommandLineData {
+    virCommandPtr cmd;
+} qemuBuildDBusVMStateCommandLineData;
+
+
+static int
+qemuBuildDBusVMStateCommandLineEach(void *payload,
+                                    const void *id,
+                                    void *user_data)
+{
+    qemuBuildDBusVMStateCommandLineData *data = user_data;
+    qemuDBusVMStatePtr vms = payload;
+    VIR_AUTOCLEAN(virBuffer) buf = VIR_BUFFER_INITIALIZER;
+    VIR_AUTOPTR(virJSONValue) props = NULL;
+
+    if (!(props = qemuBuildDBusVMStateInfoProps(id, vms->addr)))
+        return -1;
+
+    if (virQEMUBuildObjectCommandlineFromJSON(&buf, props) < 0)
+        return -1;
+
+    virCommandAddArg(data->cmd, "-object");
+    virCommandAddArgBuffer(data->cmd, &buf);
+
+    return 0;
+}
+
+static int
+qemuBuildDBusVMStateCommandLine(virCommandPtr cmd,
+                                qemuDomainObjPrivatePtr priv)
+{
+    qemuBuildDBusVMStateCommandLineData data = {
+        .cmd = cmd,
+    };
+
+    if (virHashSize(priv->dbusVMStates) == 0)
+        return 0;
+
+    if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DBUS_VMSTATE)) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                       _("dbus-vmstate object is not supported by this QEMU binary"));
+        return 0;
+    }
+
+    if (virHashForEach(priv->dbusVMStates, qemuBuildDBusVMStateCommandLineEach, &data) < 0)
+        return -1;
+
+    return 0;
+}
+
+
 /**
  * qemuBuildCommandLineValidate:
  *
@@ -10217,6 +10297,9 @@ qemuBuildCommandLine(virQEMUDriverPtr driver,
     if (qemuBuildMasterKeyCommandLine(cmd, priv) < 0)
         return NULL;
 
+    if (qemuBuildDBusVMStateCommandLine(cmd, priv) < 0)
+        return NULL;
+
     if (qemuBuildManagedPRCommandLine(cmd, def, priv) < 0)
         return NULL;
 

src/qemu/qemu_command.h

@@ -62,6 +62,9 @@ virJSONValuePtr qemuBuildPRManagedManagerInfoProps(qemuDomainObjPrivatePtr priv)
 int qemuBuildSecretInfoProps(qemuDomainSecretInfoPtr secinfo,
                              virJSONValuePtr *propsret);
 
+virJSONValuePtr qemuBuildDBusVMStateInfoProps(const char *id,
+                                              const char *addr);
+
 /* Generate the object properties for a tls-creds-x509 */
 int qemuBuildTLSx509BackendProps(const char *tlspath,
                                  bool isListen,

src/qemu/qemu_dbus.c

@@ -0,0 +1,97 @@
+/*
+ * qemu_dbus.c: QEMU DBus-related helpers
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+
+#include "qemu_extdevice.h"
+#include "qemu_dbus.h"
+#include "qemu_hotplug.h"
+#include "qemu_security.h"
+
+#include "viralloc.h"
+#include "virlog.h"
+#include "virstring.h"
+#include "virtime.h"
+#include "virpidfile.h"
+
+#define VIR_FROM_THIS VIR_FROM_QEMU
+
+VIR_LOG_INIT("qemu.dbus");
+
+
+qemuDBusVMStatePtr
+qemuDBusVMStateNew(const char *id, const char *addr)
+{
+    VIR_AUTOPTR(qemuDBusVMState) self = NULL;
+
+    if (VIR_ALLOC(self) < 0)
+        return NULL;
+
+    if (VIR_STRDUP(self->id, id) < 0)
+        return NULL;
+
+    if (VIR_STRDUP(self->addr, addr) < 0)
+        return NULL;
+
+    VIR_RETURN_PTR(self);
+}
+
+
+void
+qemuDBusVMStateFree(qemuDBusVMStatePtr self)
+{
+    if (!self)
+        return;
+
+    VIR_FREE(self->id);
+    VIR_FREE(self->addr);
+    VIR_FREE(self);
+}
+
+
+int
+qemuDBusVMStateAdd(virQEMUDriverPtr driver, virDomainObjPtr vm,
+                   const char *id, const char *addr, bool hot)
+{
+    qemuDBusVMStatePtr d = qemuDBusVMStateNew(id, addr);
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+
+    if (virHashAddEntry(priv->dbusVMStates, id, d) < 0) {
+        qemuDBusVMStateFree(d);
+        return -1;
+    }
+
+    if (hot && virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DBUS_VMSTATE) &&
+        qemuDomainAttachDBusVMState(driver, vm, id, addr, QEMU_ASYNC_JOB_NONE) < 0)
+        return -1;
+
+    return 0;
+}
+
+
+void
+qemuDBusVMStateRemove(virQEMUDriverPtr driver, virDomainObjPtr vm,
+                      const char *id, bool hot)
+{
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+
+    if (virHashRemoveEntry(priv->dbusVMStates, id) < 0 ||
+        (hot && virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DBUS_VMSTATE) &&
+         qemuDomainDetachDBusVMState(driver, vm, id, QEMU_ASYNC_JOB_NONE) < 0))
+        VIR_ERROR(_("Failed to remove vmstate id '%s'"), vm->def->name);
+}

src/qemu/qemu_dbus.h

@@ -0,0 +1,42 @@
+/*
+ * qemu_dbus.h: QEMU DBus-related helpers
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "qemu_conf.h"
+#include "qemu_domain.h"
+
+typedef struct _qemuDBusVMState qemuDBusVMState;
+typedef qemuDBusVMState *qemuDBusVMStatePtr;
+struct _qemuDBusVMState {
+    char *id;
+    char *addr;
+};
+
+
+qemuDBusVMStatePtr qemuDBusVMStateNew(const char *id, const char *addr);
+
+void qemuDBusVMStateFree(qemuDBusVMStatePtr self);
+
+int qemuDBusVMStateAdd(virQEMUDriverPtr driver, virDomainObjPtr vm,
+                       const char *id, const char *addr, bool hot);
+
+void qemuDBusVMStateRemove(virQEMUDriverPtr driver, virDomainObjPtr vm,
+                           const char *id, bool hot);
+
+VIR_DEFINE_AUTOPTR_FUNC(qemuDBusVMState, qemuDBusVMStateFree);

src/qemu/qemu_domain.c

@@ -26,6 +26,7 @@
 #include "qemu_block.h"
 #include "qemu_cgroup.h"
 #include "qemu_command.h"
+#include "qemu_dbus.h"
 #include "qemu_process.h"
 #include "qemu_capabilities.h"
 #include "qemu_migration.h"
@@ -1959,6 +1960,14 @@ qemuDomainSetPrivatePaths(virQEMUDriverPtr driver,
 }
 
 
+static void
+dbusVMStateHashFree(void *opaque,
+                    const void *name ATTRIBUTE_UNUSED)
+{
+    qemuDBusVMStateFree(opaque);
+}
+
+
 static void *
 qemuDomainObjPrivateAlloc(void *opaque)
 {
@@ -1979,6 +1988,9 @@ qemuDomainObjPrivateAlloc(void *opaque)
     if (!(priv->blockjobs = virHashCreate(5, virObjectFreeHashData)))
         goto error;
 
+    if (!(priv->dbusVMStates = virHashCreate(5, dbusVMStateHashFree)))
+        goto error;
+
     priv->migMaxBandwidth = QEMU_DOMAIN_MIG_BANDWIDTH_MAX;
     priv->driver = opaque;
 
@@ -2050,6 +2062,7 @@ qemuDomainObjPrivateDataClear(qemuDomainObjPrivatePtr priv)
     qemuDomainObjResetAsyncJob(priv);
 
     virHashRemoveAll(priv->blockjobs);
+    virHashRemoveAll(priv->dbusVMStates);
 }
 
 
@@ -2082,6 +2095,7 @@ qemuDomainObjPrivateFree(void *data)
     qemuDomainMasterKeyFree(priv);
 
     virHashFree(priv->blockjobs);
+    virHashFree(priv->dbusVMStates);
 
     VIR_FREE(priv);
 }

src/qemu/qemu_domain.h

@@ -392,6 +392,8 @@ struct _qemuDomainObjPrivate {
 
     /* running block jobs */
     virHashTablePtr blockjobs;
+
+    virHashTablePtr dbusVMStates;
 };
 
 #define QEMU_DOMAIN_PRIVATE(vm) \

src/qemu/qemu_hotplug.c

@@ -412,6 +412,83 @@ qemuHotplugRemoveManagedPR(virQEMUDriverPtr driver,
 }
 
 
+/**
+ * qemuDomainAttachDBusVMState:
+ * @driver: QEMU driver object
+ * @vm: domain object
+ * @id
+ * @addr
+ * @asyncJob: asynchronous job identifier
+ *
+ * Add dbus-vmstate object.
+ *
+ * Returns: 0 on success, -1 on error.
+ */
+int
+qemuDomainAttachDBusVMState(virQEMUDriverPtr driver,
+                            virDomainObjPtr vm,
+                            const char *id,
+                            const char *addr,
+                            qemuDomainAsyncJob asyncJob)
+{
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+    VIR_AUTOPTR(virJSONValue) props = NULL;
+    int ret;
+
+    if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DBUS_VMSTATE)) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                       _("dbus-vmstate object is not supported by this QEMU binary"));
+        return -1;
+    }
+
+    if (!(props = qemuBuildDBusVMStateInfoProps(id, addr)))
+        return -1;
+
+    if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)
+        return -1;
+
+    ret = qemuMonitorAddObject(priv->mon, &props, NULL);
+
+    if (qemuDomainObjExitMonitor(driver, vm) < 0)
+        return -1;
+
+    return ret;
+}
+
+
+/**
+ * qemuDomainDetachDBusVMState:
+ * @driver: QEMU driver object
+ * @vm: domain object
+ * @asyncJob: asynchronous job identifier
+ *
+ * Remove dbus-vmstate object from @vm.
+ *
+ * Returns: 0 on success, -1 on error.
+ */
+int
+qemuDomainDetachDBusVMState(virQEMUDriverPtr driver,
+                            virDomainObjPtr vm,
+                            const char *id,
+                            qemuDomainAsyncJob asyncJob)
+{
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+    VIR_AUTOFREE(char *) alias = qemuAliasDBusVMStateFromId(id);
+    int ret;
+
+    if (!alias ||
+        qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)
+        return -1;
+
+    ret = qemuMonitorDelObject(priv->mon, alias);
+
+    if (qemuDomainObjExitMonitor(driver, vm) < 0)
+        return -1;
+
+    return ret;
+}
+
+
 /**
  * qemuDomainChangeMediaBlockdev:
  * @driver: qemu driver structure

src/qemu/qemu_hotplug.h

@@ -150,3 +150,14 @@ int qemuDomainSetVcpuInternal(virQEMUDriverPtr driver,
                               virDomainDefPtr persistentDef,
                               virBitmapPtr vcpus,
                               bool state);
+
+int qemuDomainAttachDBusVMState(virQEMUDriverPtr driver,
+                                virDomainObjPtr vm,
+                                const char *id,
+                                const char *addr,
+                                qemuDomainAsyncJob asyncJob);
+
+int qemuDomainDetachDBusVMState(virQEMUDriverPtr driver,
+                                virDomainObjPtr vm,
+                                const char *id,
+                                qemuDomainAsyncJob asyncJob);