[Qemu-devel] [QEMU PATCH v4 0/6] migration: ensure hotplug and migration work together

[Qemu-devel] [QEMU PATCH v4 0/6] migration: ensure hotplug and migration work together

[Jianjun Duan]

Hi all,
   The previous patches seem to get buried deep somewhere. I am resending them
 without RFC tag. Comments are welcome.

v4: - Introduce a way to set customized instance_id in SaveStateEntry. Use it
      to set instance_id for DRC using its unique index to address David 
      Gibson's concern.
    - Rename VMS_CSTM to VMS_LINKED based on Paolo Bonzini's suggestions.
    - Clean up qjson stuff in put_qtailq. 
    - Add trace for put_qtailq and get_qtailq based on David Gilbert's 
      suggestion.

It is based on David's ppc-for-2.7. Comments are welcome. Previous versions are:

v3: - Simplify overall design followng discussion with Paolo. No longer need
      metadata to migrate QTAILQ.
    - Extend VMStateInfo instead of adding similar fields to VMStateField.
    - Clean up macros in qemu/queue.h.
(link: https://lists.nongnu.org/archive/html/qemu-devel/2016-05/msg05695.html)

v2: - Introduce a general approach to migrate QTAILQ in qemu/queue.h.
    - Migrate signalled field in the DRC state.
    - Put the newly added migrating fields in subsections so that backward 
      migration is not broken.  
    - Set detach_cb field right after migration so that a migrated hot-unplug
      event could finish its course.
(link: https://lists.nongnu.org/archive/html/qemu-devel/2016-05/msg04188.html)

v1: - Inital version.
(link: https://lists.nongnu.org/archive/html/qemu-devel/2016-04/msg02601.html)

To make guest device (PCI, CPU and memory) hotplug work together 
with guest migration, spapr drc state needs be transmitted in
migration. This patch defines the VMStateDescription struct for
spapr drc state to enable it.

To fix the potential racing between hotplug events on guest and 
guest migration, ccs_list and pending_events of spapr state need be 
transmitted in migration. This patch also takes care of it.

Jianjun Duan (6):
  migration: alternative way to set instance_id in SaveStateEntry
  migration: spapr_drc: defined VMStateDescription struct
  migration: extend VMStateInfo
  migration: migrate QTAILQ
  migration: spapr: migrate ccs_list in spapr state
  migration: spapr: migrate pending_events of spapr state

 hw/net/vmxnet3.c            |  18 +++--
 hw/nvram/eeprom93xx.c       |   6 +-
 hw/nvram/fw_cfg.c           |   6 +-
 hw/pci/msix.c               |   6 +-
 hw/pci/pci.c                |  12 ++--
 hw/pci/shpc.c               |   5 +-
 hw/ppc/spapr.c              |  67 ++++++++++++++++++
 hw/ppc/spapr_drc.c          |  69 +++++++++++++++++++
 hw/ppc/spapr_events.c       |  22 +++---
 hw/ppc/spapr_pci.c          |  22 ++++++
 hw/scsi/scsi-bus.c          |   6 +-
 hw/timer/twl92230.c         |   6 +-
 hw/usb/redirect.c           |  18 +++--
 hw/virtio/virtio-pci.c      |   6 +-
 hw/virtio/virtio.c          |   6 +-
 include/hw/ppc/spapr.h      |   3 +-
 include/hw/ppc/spapr_drc.h  |   9 +++
 include/hw/qdev-core.h      |   6 ++
 include/migration/vmstate.h |  36 ++++++++--
 include/qemu/queue.h        |  32 +++++++++
 migration/savevm.c          |  25 +++++--
 migration/vmstate.c         | 161 ++++++++++++++++++++++++++++++++++----------
 target-alpha/machine.c      |   5 +-
 target-arm/machine.c        |  12 ++--
 target-i386/machine.c       |  21 ++++--
 target-mips/machine.c       |  10 +--
 target-ppc/machine.c        |  10 +--
 target-sparc/machine.c      |   5 +-
 trace-events                |   4 ++
 29 files changed, 505 insertions(+), 109 deletions(-)

-- 
1.9.1

[Qemu-devel] [QEMU PATCH v4 1/6] migration: alternative way to set instance_id in SaveStateEntry

[Jianjun Duan]

In QOM(QEMU Object Model) migrated objects are identified with instance_id
which is calculated automatically using their path in the QOM composition
tree. For some objects, this path could change from source to target in
migration. To migrate such objects, we need to make sure the instance_id does
not change from source to target. We add a hook in DeviceClass to do customized
instance_id calculation in such cases.

As a result, in these cases compat will not be set in the concerned
SaveStateEntry. This will prevent the inconsistent idstr to be sent over in
migration. We could have set alias_id in a similar way. But that will be
overloading the purpose of alias_id.

The first application will be setting instance_id for DRC using its unique
index. Doing this makes the instance_id of DRC to be consistent across migration
and supports flexible management of DRC objects in migration.

Signed-off-by: Jianjun Duan <duanj@linux.vnet.ibm.com>
---
 include/hw/qdev-core.h |  6 ++++++
 migration/savevm.c     | 20 ++++++++++++++++++--
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index 1ce02b2..28173a7 100644
--- a/include/hw/qdev-core.h
+++ b/include/hw/qdev-core.h
@@ -139,6 +139,12 @@ typedef struct DeviceClass {
     qdev_initfn init; /* TODO remove, once users are converted to realize */
     qdev_event exit; /* TODO remove, once users are converted to unrealize */
     const char *bus_type;
+
+    /* When this field is set, qemu will use it to get an unique instance_id
+     * instead of calculating an auto idstr and instanc_id for the relevant
+     * SaveStateEntry
+     */
+    int (*dev_get_instance_id)(DeviceState *dev);
 } DeviceClass;
 
 typedef struct NamedGPIOList NamedGPIOList;
diff --git a/migration/savevm.c b/migration/savevm.c
index 6c21231..f7e7c68 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -494,6 +494,11 @@ int register_savevm_live(DeviceState *dev,
                          void *opaque)
 {
     SaveStateEntry *se;
+    /* when it is a device and it provides a way to get instance_id,
+     * we will use it and skip setting idstr and compat.
+     */
+    bool flag = (dev != NULL) &&
+                (DEVICE_GET_CLASS(dev)->dev_get_instance_id != NULL);
 
     se = g_new0(SaveStateEntry, 1);
     se->version_id = version_id;
@@ -506,7 +511,7 @@ int register_savevm_live(DeviceState *dev,
         se->is_ram = 1;
     }
 
-    if (dev) {
+    if (dev && !flag) {
         char *id = qdev_get_dev_path(dev);
         if (id) {
             pstrcpy(se->idstr, sizeof(se->idstr), id);
@@ -522,6 +527,9 @@ int register_savevm_live(DeviceState *dev,
     }
     pstrcat(se->idstr, sizeof(se->idstr), idstr);
 
+    if (flag) {
+        instance_id = DEVICE_GET_CLASS(dev)->dev_get_instance_id(dev);
+    }
     if (instance_id == -1) {
         se->instance_id = calculate_new_instance_id(se->idstr);
     } else {
@@ -579,6 +587,11 @@ int vmstate_register_with_alias_id(DeviceState *dev, int instance_id,
                                    int required_for_version)
 {
     SaveStateEntry *se;
+    /* when it is a device and it provides a way to get instance_id,
+     * we will use it and skip setting idstr and compat.
+     */
+    bool flag = (dev != NULL) &&
+                (DEVICE_GET_CLASS(dev)->dev_get_instance_id != NULL);
 
     /* If this triggers, alias support can be dropped for the vmsd. */
     assert(alias_id == -1 || required_for_version >= vmsd->minimum_version_id);
@@ -590,7 +603,7 @@ int vmstate_register_with_alias_id(DeviceState *dev, int instance_id,
     se->vmsd = vmsd;
     se->alias_id = alias_id;
 
-    if (dev) {
+    if (dev && !flag) {
         char *id = qdev_get_dev_path(dev);
         if (id) {
             pstrcpy(se->idstr, sizeof(se->idstr), id);
@@ -606,6 +619,9 @@ int vmstate_register_with_alias_id(DeviceState *dev, int instance_id,
     }
     pstrcat(se->idstr, sizeof(se->idstr), vmsd->name);
 
+    if (flag) {
+        instance_id = DEVICE_GET_CLASS(dev)->dev_get_instance_id(dev);
+    }
     if (instance_id == -1) {
         se->instance_id = calculate_new_instance_id(se->idstr);
     } else {
-- 
1.9.1

[Qemu-devel] [QEMU PATCH v4 2/6] migration: spapr_drc: defined VMStateDescription struct

[Jianjun Duan]

To manage hotplug/unplug of dynamic resources such as PCI cards,
memory, and CPU on sPAPR guests, a firmware abstraction known as
a Dynamic Resource Connector (DRC) is used to assign a particular
dynamic resource to the guest, and provide an interface for the
guest to manage configuration/removal of the resource associated
with it.

To migrate the hotplugged resources in migration, the
associated DRC state need be migrated. To migrate the DRC state,
we defined the VMStateDescription struct for spapr_drc to enable
the transmission of spapr_drc state in migration.

Not all the elements in the DRC state are migrated. Only those
ones modifiable or needed by guest actions or device add/remove
operation are migrated. From the perspective of device
hotplugging, if we hotplug a device on the source, we need to
"coldplug" it on the target. The states across two hosts for the
same device are not the same. Ideally we want the states be same
after migration so that the device would function as hotplugged
on the target. For example we can unplug it. The minimum DRC
state we need to transfer should cover all the pieces changed by
hotplugging. Out of the elements of the DRC state, isolation_state,
allocation_sate, and configured are involved in the DR state
transition diagram from PAPR+ 2.7, 13.4. configured and signalled
are needed in attaching and detaching devices. indicator_state
provides users with hardware state information. These 6 elements
are migrated.

detach_cb in the DRC state is a function pointer that cannot be
migrated. We set it right after DRC state is migrated so that
a migrated hot-unplug event could finish its work.

The instance_id is used to identify objects in migration. We set
instance_id of DRC using the unique index so that it is the same
across migration.

Signed-off-by: Jianjun Duan <duanj@linux.vnet.ibm.com>
---
 hw/ppc/spapr_drc.c         | 69 ++++++++++++++++++++++++++++++++++++++++++++++
 hw/ppc/spapr_pci.c         | 22 +++++++++++++++
 include/hw/ppc/spapr_drc.h |  9 ++++++
 3 files changed, 100 insertions(+)

diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c
index 94c875d..7e6161d 100644
--- a/hw/ppc/spapr_drc.c
+++ b/hw/ppc/spapr_drc.c
@@ -617,6 +617,71 @@ static void spapr_dr_connector_instance_init(Object *obj)
                         NULL, NULL, NULL, NULL);
 }
 
+static bool spapr_drc_needed(void *opaque)
+{
+    sPAPRDRConnector *drc = (sPAPRDRConnector *)opaque;
+    sPAPRDRConnectorClass *drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
+    bool rc = false;
+    sPAPRDREntitySense value;
+
+    drck->entity_sense(drc, &value);
+    /* If no dev is plugged in there is no need to migrate the DRC state */
+    if (value != SPAPR_DR_ENTITY_SENSE_PRESENT) {
+        return false;
+    }
+    /*
+     * If there is dev plugged in, we need to migrate the DRC state when
+     * it is different from cold-plugged state
+     */
+    switch(drc->type) {
+    /* for PCI type */
+    case SPAPR_DR_CONNECTOR_TYPE_PCI:
+        rc = !((drc->isolation_state == SPAPR_DR_ISOLATION_STATE_UNISOLATED) &&
+               (drc->allocation_state == SPAPR_DR_ALLOCATION_STATE_USABLE) &&
+               drc->configured && drc->signalled && !drc->awaiting_release);
+        break;
+    /* for LMB type */
+    case SPAPR_DR_CONNECTOR_TYPE_LMB:
+        rc = !((drc->isolation_state == SPAPR_DR_ISOLATION_STATE_ISOLATED) &&
+               (drc->allocation_state == SPAPR_DR_ALLOCATION_STATE_UNUSABLE) &&
+               drc->configured && drc->signalled && !drc->awaiting_release);
+        break;
+    default:
+        ;
+    }
+
+    return rc;
+}
+
+/* detach_cb needs be set since it is not migrated */
+static void postmigrate_set_detach_cb(sPAPRDRConnector *drc,
+                                      spapr_drc_detach_cb *detach_cb)
+{
+    drc->detach_cb = detach_cb;
+}
+
+/* return the unique drc index as instance_id for qom interfaces*/
+static int get_instance_id(DeviceState *dev)
+{
+    return (int)get_index(SPAPR_DR_CONNECTOR(OBJECT(dev)));
+}
+
+static const VMStateDescription vmstate_spapr_drc = {
+    .name = "spapr_drc",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = spapr_drc_needed,
+    .fields  = (VMStateField []) {
+        VMSTATE_UINT32(isolation_state, sPAPRDRConnector),
+        VMSTATE_UINT32(allocation_state, sPAPRDRConnector),
+        VMSTATE_UINT32(indicator_state, sPAPRDRConnector),
+        VMSTATE_BOOL(configured, sPAPRDRConnector),
+        VMSTATE_BOOL(awaiting_release, sPAPRDRConnector),
+        VMSTATE_BOOL(signalled, sPAPRDRConnector),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static void spapr_dr_connector_class_init(ObjectClass *k, void *data)
 {
     DeviceClass *dk = DEVICE_CLASS(k);
@@ -625,6 +690,8 @@ static void spapr_dr_connector_class_init(ObjectClass *k, void *data)
     dk->reset = reset;
     dk->realize = realize;
     dk->unrealize = unrealize;
+    dk->vmsd = &vmstate_spapr_drc;
+    dk->dev_get_instance_id = get_instance_id;
     drck->set_isolation_state = set_isolation_state;
     drck->set_indicator_state = set_indicator_state;
     drck->set_allocation_state = set_allocation_state;
@@ -638,6 +705,8 @@ static void spapr_dr_connector_class_init(ObjectClass *k, void *data)
     drck->detach = detach;
     drck->release_pending = release_pending;
     drck->set_signalled = set_signalled;
+    drck->postmigrate_set_detach_cb = postmigrate_set_detach_cb;
+
     /*
      * Reason: it crashes FIXME find and document the real reason
      */
diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index 68de523..e03cec8 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -1575,11 +1575,33 @@ static void spapr_pci_pre_save(void *opaque)
     }
 }
 
+/*
+ * detach_cb in the DRC state is a function pointer that cannot be
+ * migrated. We set it right after migration so that a migrated
+ * hot-unplug event could finish its work.
+ */
+static void spapr_pci_set_detach_cb(PCIBus *bus, PCIDevice *pdev,
+                                 void *opaque)
+{
+    sPAPRPHBState *sphb = opaque;
+    sPAPRDRConnector *drc = spapr_phb_get_pci_drc(sphb, pdev);
+    sPAPRDRConnectorClass *drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
+    drck->postmigrate_set_detach_cb(drc, spapr_phb_remove_pci_device_cb);
+}
+
 static int spapr_pci_post_load(void *opaque, int version_id)
 {
     sPAPRPHBState *sphb = opaque;
     gpointer key, value;
     int i;
+    PCIBus *bus = PCI_HOST_BRIDGE(sphb)->bus;
+    unsigned int bus_no = 0;
+
+    /* Set detach_cb for the drc unconditionally after migration */
+    if (bus) {
+        pci_for_each_device(bus, pci_bus_num(bus), spapr_pci_set_detach_cb,
+                            &bus_no);
+    }
 
     for (i = 0; i < sphb->msi_devs_num; ++i) {
         key = g_memdup(&sphb->msi_devs[i].key,
diff --git a/include/hw/ppc/spapr_drc.h b/include/hw/ppc/spapr_drc.h
index fa21ba0..a68433b 100644
--- a/include/hw/ppc/spapr_drc.h
+++ b/include/hw/ppc/spapr_drc.h
@@ -190,6 +190,15 @@ typedef struct sPAPRDRConnectorClass {
                    void *detach_cb_opaque, Error **errp);
     bool (*release_pending)(sPAPRDRConnector *drc);
     void (*set_signalled)(sPAPRDRConnector *drc);
+
+    /*
+     * QEMU interface for setting detach_cb after migration.
+     * detach_cb in the DRC state is a function pointer that cannot be
+     * migrated. We set it right after migration so that a migrated
+     * hot-unplug event could finish its work.
+     */
+    void (*postmigrate_set_detach_cb)(sPAPRDRConnector *drc,
+                                      spapr_drc_detach_cb *detach_cb);
 } sPAPRDRConnectorClass;
 
 sPAPRDRConnector *spapr_dr_connector_new(Object *owner,
-- 
1.9.1

[Qemu-devel] [QEMU PATCH v4 3/6] migration: extend VMStateInfo

[Jianjun Duan]

Current migration code cannot handle some data structures such as
QTAILQ in qemu/queue.h. Here we extend the signatures of put/get
in VMStateInfo so that customized handling is supported.

Signed-off-by: Jianjun Duan <duanj@linux.vnet.ibm.com>
---
 hw/net/vmxnet3.c            | 18 ++++++---
 hw/nvram/eeprom93xx.c       |  6 ++-
 hw/nvram/fw_cfg.c           |  6 ++-
 hw/pci/msix.c               |  6 ++-
 hw/pci/pci.c                | 12 ++++--
 hw/pci/shpc.c               |  5 ++-
 hw/scsi/scsi-bus.c          |  6 ++-
 hw/timer/twl92230.c         |  6 ++-
 hw/usb/redirect.c           | 18 ++++++---
 hw/virtio/virtio-pci.c      |  6 ++-
 hw/virtio/virtio.c          |  6 ++-
 include/migration/vmstate.h | 10 +++--
 migration/savevm.c          |  5 ++-
 migration/vmstate.c         | 95 ++++++++++++++++++++++++++++-----------------
 target-alpha/machine.c      |  5 ++-
 target-arm/machine.c        | 12 ++++--
 target-i386/machine.c       | 21 ++++++----
 target-mips/machine.c       | 10 +++--
 target-ppc/machine.c        | 10 +++--
 target-sparc/machine.c      |  5 ++-
 20 files changed, 171 insertions(+), 97 deletions(-)

diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c
index 16645e6..7ddec0b 100644
--- a/hw/net/vmxnet3.c
+++ b/hw/net/vmxnet3.c
@@ -2445,7 +2445,8 @@ static void vmxnet3_put_tx_stats_to_file(QEMUFile *f,
     qemu_put_be64(f, tx_stat->pktsTxDiscard);
 }
 
-static int vmxnet3_get_txq_descr(QEMUFile *f, void *pv, size_t size)
+static int vmxnet3_get_txq_descr(QEMUFile *f, void *pv, size_t size,
+    VMStateField *field)
 {
     Vmxnet3TxqDescr *r = pv;
 
@@ -2459,7 +2460,8 @@ static int vmxnet3_get_txq_descr(QEMUFile *f, void *pv, size_t size)
     return 0;
 }
 
-static void vmxnet3_put_txq_descr(QEMUFile *f, void *pv, size_t size)
+static void vmxnet3_put_txq_descr(QEMUFile *f, void *pv, size_t size,
+    VMStateField *field, QJSON *vmdesc)
 {
     Vmxnet3TxqDescr *r = pv;
 
@@ -2506,7 +2508,8 @@ static void vmxnet3_put_rx_stats_to_file(QEMUFile *f,
     qemu_put_be64(f, rx_stat->pktsRxError);
 }
 
-static int vmxnet3_get_rxq_descr(QEMUFile *f, void *pv, size_t size)
+static int vmxnet3_get_rxq_descr(QEMUFile *f, void *pv, size_t size,
+    VMStateField *field)
 {
     Vmxnet3RxqDescr *r = pv;
     int i;
@@ -2524,7 +2527,8 @@ static int vmxnet3_get_rxq_descr(QEMUFile *f, void *pv, size_t size)
     return 0;
 }
 
-static void vmxnet3_put_rxq_descr(QEMUFile *f, void *pv, size_t size)
+static void vmxnet3_put_rxq_descr(QEMUFile *f, void *pv, size_t size,
+    VMStateField *field, QJSON *vmdesc)
 {
     Vmxnet3RxqDescr *r = pv;
     int i;
@@ -2569,7 +2573,8 @@ static const VMStateInfo rxq_descr_info = {
     .put = vmxnet3_put_rxq_descr
 };
 
-static int vmxnet3_get_int_state(QEMUFile *f, void *pv, size_t size)
+static int vmxnet3_get_int_state(QEMUFile *f, void *pv, size_t size,
+    VMStateField *field)
 {
     Vmxnet3IntState *r = pv;
 
@@ -2580,7 +2585,8 @@ static int vmxnet3_get_int_state(QEMUFile *f, void *pv, size_t size)
     return 0;
 }
 
-static void vmxnet3_put_int_state(QEMUFile *f, void *pv, size_t size)
+static void vmxnet3_put_int_state(QEMUFile *f, void *pv, size_t size,
+    VMStateField *field, QJSON *vmdesc)
 {
     Vmxnet3IntState *r = pv;
 
diff --git a/hw/nvram/eeprom93xx.c b/hw/nvram/eeprom93xx.c
index 2c16fc2..76d5f41 100644
--- a/hw/nvram/eeprom93xx.c
+++ b/hw/nvram/eeprom93xx.c
@@ -94,14 +94,16 @@ struct _eeprom_t {
    This is a Big hack, but it is how the old state did it.
  */
 
-static int get_uint16_from_uint8(QEMUFile *f, void *pv, size_t size)
+static int get_uint16_from_uint8(QEMUFile *f, void *pv, size_t size,
+                                 VMStateField *field)
 {
     uint16_t *v = pv;
     *v = qemu_get_ubyte(f);
     return 0;
 }
 
-static void put_unused(QEMUFile *f, void *pv, size_t size)
+static void put_unused(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                       QJSON *vmdesc)
 {
     fprintf(stderr, "uint16_from_uint8 is used only for backwards compatibility.\n");
     fprintf(stderr, "Never should be used to write a new state.\n");
diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index cdbdfb5..c294f9a 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -524,14 +524,16 @@ static void fw_cfg_reset(DeviceState *d)
    Or we broke compatibility in the state, or we can't use struct tm
  */
 
-static int get_uint32_as_uint16(QEMUFile *f, void *pv, size_t size)
+static int get_uint32_as_uint16(QEMUFile *f, void *pv, size_t size,
+                                VMStateField *field)
 {
     uint32_t *v = pv;
     *v = qemu_get_be16(f);
     return 0;
 }
 
-static void put_unused(QEMUFile *f, void *pv, size_t size)
+static void put_unused(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                       QJSON *vmdesc)
 {
     fprintf(stderr, "uint32_as_uint16 is only used for backward compatibility.\n");
     fprintf(stderr, "This functions shouldn't be called.\n");
diff --git a/hw/pci/msix.c b/hw/pci/msix.c
index 0ec1cb1..69e7a50 100644
--- a/hw/pci/msix.c
+++ b/hw/pci/msix.c
@@ -587,12 +587,14 @@ void msix_unset_vector_notifiers(PCIDevice *dev)
     dev->msix_vector_poll_notifier = NULL;
 }
 
-static void put_msix_state(QEMUFile *f, void *pv, size_t size)
+static void put_msix_state(QEMUFile *f, void *pv, size_t size,
+                           VMStateField *field, QJSON *vmdesc)
 {
     msix_save(pv, f);
 }
 
-static int get_msix_state(QEMUFile *f, void *pv, size_t size)
+static int get_msix_state(QEMUFile *f, void *pv, size_t size,
+                          VMStateField *field)
 {
     msix_load(pv, f);
     return 0;
diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index bb605ef..75abae6 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -414,7 +414,8 @@ int pci_bus_numa_node(PCIBus *bus)
     return PCI_BUS_GET_CLASS(bus)->numa_node(bus);
 }
 
-static int get_pci_config_device(QEMUFile *f, void *pv, size_t size)
+static int get_pci_config_device(QEMUFile *f, void *pv, size_t size,
+                                 VMStateField *field)
 {
     PCIDevice *s = container_of(pv, PCIDevice, config);
     PCIDeviceClass *pc = PCI_DEVICE_GET_CLASS(s);
@@ -453,7 +454,8 @@ static int get_pci_config_device(QEMUFile *f, void *pv, size_t size)
 }
 
 /* just put buffer */
-static void put_pci_config_device(QEMUFile *f, void *pv, size_t size)
+static void put_pci_config_device(QEMUFile *f, void *pv, size_t size,
+                                  VMStateField *field, QJSON *vmdesc)
 {
     const uint8_t **v = pv;
     assert(size == pci_config_size(container_of(pv, PCIDevice, config)));
@@ -466,7 +468,8 @@ static VMStateInfo vmstate_info_pci_config = {
     .put  = put_pci_config_device,
 };
 
-static int get_pci_irq_state(QEMUFile *f, void *pv, size_t size)
+static int get_pci_irq_state(QEMUFile *f, void *pv, size_t size,
+                             VMStateField *field)
 {
     PCIDevice *s = container_of(pv, PCIDevice, irq_state);
     uint32_t irq_state[PCI_NUM_PINS];
@@ -487,7 +490,8 @@ static int get_pci_irq_state(QEMUFile *f, void *pv, size_t size)
     return 0;
 }
 
-static void put_pci_irq_state(QEMUFile *f, void *pv, size_t size)
+static void put_pci_irq_state(QEMUFile *f, void *pv, size_t size,
+                              VMStateField *field, QJSON *vmdesc)
 {
     int i;
     PCIDevice *s = container_of(pv, PCIDevice, irq_state);
diff --git a/hw/pci/shpc.c b/hw/pci/shpc.c
index 3dcd472..9f82aa6 100644
--- a/hw/pci/shpc.c
+++ b/hw/pci/shpc.c
@@ -695,13 +695,14 @@ void shpc_cap_write_config(PCIDevice *d, uint32_t addr, uint32_t val, int l)
     shpc_cap_update_dword(d);
 }
 
-static void shpc_save(QEMUFile *f, void *pv, size_t size)
+static void shpc_save(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                QJSON *vmdesc)
 {
     PCIDevice *d = container_of(pv, PCIDevice, shpc);
     qemu_put_buffer(f, d->shpc->config, SHPC_SIZEOF(d));
 }
 
-static int shpc_load(QEMUFile *f, void *pv, size_t size)
+static int shpc_load(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     PCIDevice *d = container_of(pv, PCIDevice, shpc);
     int ret = qemu_get_buffer(f, d->shpc->config, SHPC_SIZEOF(d));
diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
index ad6f398..ae2bfa2 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -1906,7 +1906,8 @@ SCSIDevice *scsi_device_find(SCSIBus *bus, int channel, int id, int lun)
 
 /* SCSI request list.  For simplicity, pv points to the whole device */
 
-static void put_scsi_requests(QEMUFile *f, void *pv, size_t size)
+static void put_scsi_requests(QEMUFile *f, void *pv, size_t size,
+                              VMStateField *field, QJSON *vmdesc)
 {
     SCSIDevice *s = pv;
     SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, s->qdev.parent_bus);
@@ -1931,7 +1932,8 @@ static void put_scsi_requests(QEMUFile *f, void *pv, size_t size)
     qemu_put_sbyte(f, 0);
 }
 
-static int get_scsi_requests(QEMUFile *f, void *pv, size_t size)
+static int get_scsi_requests(QEMUFile *f, void *pv, size_t size,
+                             VMStateField *field)
 {
     SCSIDevice *s = pv;
     SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, s->qdev.parent_bus);
diff --git a/hw/timer/twl92230.c b/hw/timer/twl92230.c
index 7ba4e9a..95eb7f3 100644
--- a/hw/timer/twl92230.c
+++ b/hw/timer/twl92230.c
@@ -747,14 +747,16 @@ static int menelaus_rx(I2CSlave *i2c)
    Or we broke compatibility in the state, or we can't use struct tm
  */
 
-static int get_int32_as_uint16(QEMUFile *f, void *pv, size_t size)
+static int get_int32_as_uint16(QEMUFile *f, void *pv, size_t size,
+                               VMStateField *field)
 {
     int *v = pv;
     *v = qemu_get_be16(f);
     return 0;
 }
 
-static void put_int32_as_uint16(QEMUFile *f, void *pv, size_t size)
+static void put_int32_as_uint16(QEMUFile *f, void *pv, size_t size,
+                                VMStateField *field, QJSON *vmdesc)
 {
     int *v = pv;
     qemu_put_be16(f, *v);
diff --git a/hw/usb/redirect.c b/hw/usb/redirect.c
index 8d80540..806af1b 100644
--- a/hw/usb/redirect.c
+++ b/hw/usb/redirect.c
@@ -2151,7 +2151,8 @@ static int usbredir_post_load(void *priv, int version_id)
 }
 
 /* For usbredirparser migration */
-static void usbredir_put_parser(QEMUFile *f, void *priv, size_t unused)
+static void usbredir_put_parser(QEMUFile *f, void *priv, size_t unused,
+                                void *opaque, QJSON *vmdesc)
 {
     USBRedirDevice *dev = priv;
     uint8_t *data;
@@ -2171,7 +2172,8 @@ static void usbredir_put_parser(QEMUFile *f, void *priv, size_t unused)
     free(data);
 }
 
-static int usbredir_get_parser(QEMUFile *f, void *priv, size_t unused)
+static int usbredir_get_parser(QEMUFile *f, void *priv, size_t unused,
+                               void *opaque)
 {
     USBRedirDevice *dev = priv;
     uint8_t *data;
@@ -2214,7 +2216,8 @@ static const VMStateInfo usbredir_parser_vmstate_info = {
 
 
 /* For buffered packets (iso/irq) queue migration */
-static void usbredir_put_bufpq(QEMUFile *f, void *priv, size_t unused)
+static void usbredir_put_bufpq(QEMUFile *f, void *priv, size_t unused,
+                               VMStateField *field, QJSON *vmdesc)
 {
     struct endp_data *endp = priv;
     USBRedirDevice *dev = endp->dev;
@@ -2234,7 +2237,8 @@ static void usbredir_put_bufpq(QEMUFile *f, void *priv, size_t unused)
     assert(i == endp->bufpq_size);
 }
 
-static int usbredir_get_bufpq(QEMUFile *f, void *priv, size_t unused)
+static int usbredir_get_bufpq(QEMUFile *f, void *priv, size_t unused,
+                              VMStateField *field)
 {
     struct endp_data *endp = priv;
     USBRedirDevice *dev = endp->dev;
@@ -2337,7 +2341,8 @@ static const VMStateDescription usbredir_ep_vmstate = {
 
 
 /* For PacketIdQueue migration */
-static void usbredir_put_packet_id_q(QEMUFile *f, void *priv, size_t unused)
+static void usbredir_put_packet_id_q(QEMUFile *f, void *priv, size_t unused,
+                                     VMStateField *field, QJSON *vmdesc)
 {
     struct PacketIdQueue *q = priv;
     USBRedirDevice *dev = q->dev;
@@ -2353,7 +2358,8 @@ static void usbredir_put_packet_id_q(QEMUFile *f, void *priv, size_t unused)
     assert(remain == 0);
 }
 
-static int usbredir_get_packet_id_q(QEMUFile *f, void *priv, size_t unused)
+static int usbredir_get_packet_id_q(QEMUFile *f, void *priv, size_t unused,
+                                    VMStateField *field)
 {
     struct PacketIdQueue *q = priv;
     USBRedirDevice *dev = q->dev;
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index bfedbbf..79914c2 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -108,7 +108,8 @@ static bool virtio_pci_has_extra_state(DeviceState *d)
     return proxy->flags & VIRTIO_PCI_FLAG_MIGRATE_EXTRA;
 }
 
-static int get_virtio_pci_modern_state(QEMUFile *f, void *pv, size_t size)
+static int get_virtio_pci_modern_state(QEMUFile *f, void *pv, size_t size,
+                                       VMStateField *field)
 {
     VirtIOPCIProxy *proxy = pv;
     int i;
@@ -137,7 +138,8 @@ static void virtio_pci_save_modern_queue_state(VirtIOPCIQueue *vq,
     qemu_put_be32(f, vq->used[1]);
 }
 
-static void put_virtio_pci_modern_state(QEMUFile *f, void *pv, size_t size)
+static void put_virtio_pci_modern_state(QEMUFile *f, void *pv, size_t size,
+                                        VMStateField *field, QJSON *vmdesc)
 {
     VirtIOPCIProxy *proxy = pv;
     int i;
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 30ede3d..b5e0e54 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -1314,7 +1314,8 @@ static const VMStateDescription vmstate_virtio_ringsize = {
     }
 };
 
-static int get_extra_state(QEMUFile *f, void *pv, size_t size)
+static int get_extra_state(QEMUFile *f, void *pv, size_t size,
+                           VMStateField *field)
 {
     VirtIODevice *vdev = pv;
     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
@@ -1327,7 +1328,8 @@ static int get_extra_state(QEMUFile *f, void *pv, size_t size)
     }
 }
 
-static void put_extra_state(QEMUFile *f, void *pv, size_t size)
+static void put_extra_state(QEMUFile *f, void *pv, size_t size,
+                            VMStateField *field, QJSON *vmdesc)
 {
     VirtIODevice *vdev = pv;
     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index 6c65811..56a4171 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -80,11 +80,13 @@ void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque);
 
 typedef struct VMStateInfo VMStateInfo;
 typedef struct VMStateDescription VMStateDescription;
+typedef struct VMStateField VMStateField;
 
 struct VMStateInfo {
     const char *name;
-    int (*get)(QEMUFile *f, void *pv, size_t size);
-    void (*put)(QEMUFile *f, void *pv, size_t size);
+    int (*get)(QEMUFile *f, void *pv, size_t size, VMStateField *field);
+    void (*put)(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                QJSON *vmdesc);
 };
 
 enum VMStateFlags {
@@ -185,7 +187,7 @@ enum VMStateFlags {
     VMS_MULTIPLY_ELEMENTS = 0x4000,
 };
 
-typedef struct {
+struct VMStateField {
     const char *name;
     size_t offset;
     size_t size;
@@ -198,7 +200,7 @@ typedef struct {
     const VMStateDescription *vmsd;
     int version_id;
     bool (*field_exists)(void *opaque, int version_id);
-} VMStateField;
+};
 
 struct VMStateDescription {
     const char *name;
diff --git a/migration/savevm.c b/migration/savevm.c
index f7e7c68..27a372d 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -219,14 +219,15 @@ void timer_get(QEMUFile *f, QEMUTimer *ts)
  * Not in vmstate.c to not add qemu-timer.c as dependency to vmstate.c
  */
 
-static int get_timer(QEMUFile *f, void *pv, size_t size)
+static int get_timer(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     QEMUTimer *v = pv;
     timer_get(f, v);
     return 0;
 }
 
-static void put_timer(QEMUFile *f, void *pv, size_t size)
+static void put_timer(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                QJSON *vmdesc)
 {
     QEMUTimer *v = pv;
     timer_put(f, v);
diff --git a/migration/vmstate.c b/migration/vmstate.c
index 46dc55e..644ba1f 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -121,7 +121,7 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
                     ret = vmstate_load_state(f, field->vmsd, addr,
                                              field->vmsd->version_id);
                 } else {
-                    ret = field->info->get(f, addr, size);
+                    ret = field->info->get(f, addr, size, NULL);
 
                 }
                 if (ret >= 0) {
@@ -327,7 +327,7 @@ void vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
                 if (field->flags & VMS_STRUCT) {
                     vmstate_save_state(f, field->vmsd, addr, vmdesc_loop);
                 } else {
-                    field->info->put(f, addr, size);
+                    field->info->put(f, addr, size, NULL, NULL);
                 }
 
                 written_bytes = qemu_ftell_fast(f) - old_offset;
@@ -460,14 +460,15 @@ static void vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
 
 /* bool */
 
-static int get_bool(QEMUFile *f, void *pv, size_t size)
+static int get_bool(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     bool *v = pv;
     *v = qemu_get_byte(f);
     return 0;
 }
 
-static void put_bool(QEMUFile *f, void *pv, size_t size)
+static void put_bool(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                     QJSON *vmdesc)
 {
     bool *v = pv;
     qemu_put_byte(f, *v);
@@ -481,14 +482,15 @@ const VMStateInfo vmstate_info_bool = {
 
 /* 8 bit int */
 
-static int get_int8(QEMUFile *f, void *pv, size_t size)
+static int get_int8(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     int8_t *v = pv;
     qemu_get_s8s(f, v);
     return 0;
 }
 
-static void put_int8(QEMUFile *f, void *pv, size_t size)
+static void put_int8(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                     QJSON *vmdesc)
 {
     int8_t *v = pv;
     qemu_put_s8s(f, v);
@@ -502,14 +504,15 @@ const VMStateInfo vmstate_info_int8 = {
 
 /* 16 bit int */
 
-static int get_int16(QEMUFile *f, void *pv, size_t size)
+static int get_int16(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     int16_t *v = pv;
     qemu_get_sbe16s(f, v);
     return 0;
 }
 
-static void put_int16(QEMUFile *f, void *pv, size_t size)
+static void put_int16(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                      QJSON *vmdesc)
 {
     int16_t *v = pv;
     qemu_put_sbe16s(f, v);
@@ -523,14 +526,15 @@ const VMStateInfo vmstate_info_int16 = {
 
 /* 32 bit int */
 
-static int get_int32(QEMUFile *f, void *pv, size_t size)
+static int get_int32(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     int32_t *v = pv;
     qemu_get_sbe32s(f, v);
     return 0;
 }
 
-static void put_int32(QEMUFile *f, void *pv, size_t size)
+static void put_int32(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                      QJSON *vmdesc)
 {
     int32_t *v = pv;
     qemu_put_sbe32s(f, v);
@@ -545,7 +549,8 @@ const VMStateInfo vmstate_info_int32 = {
 /* 32 bit int. See that the received value is the same than the one
    in the field */
 
-static int get_int32_equal(QEMUFile *f, void *pv, size_t size)
+static int get_int32_equal(QEMUFile *f, void *pv, size_t size,
+                           VMStateField *field)
 {
     int32_t *v = pv;
     int32_t v2;
@@ -567,7 +572,7 @@ const VMStateInfo vmstate_info_int32_equal = {
  * and less than or equal to the one in the field.
  */
 
-static int get_int32_le(QEMUFile *f, void *pv, size_t size)
+static int get_int32_le(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     int32_t *cur = pv;
     int32_t loaded;
@@ -588,14 +593,15 @@ const VMStateInfo vmstate_info_int32_le = {
 
 /* 64 bit int */
 
-static int get_int64(QEMUFile *f, void *pv, size_t size)
+static int get_int64(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     int64_t *v = pv;
     qemu_get_sbe64s(f, v);
     return 0;
 }
 
-static void put_int64(QEMUFile *f, void *pv, size_t size)
+static void put_int64(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                      QJSON *vmdesc)
 {
     int64_t *v = pv;
     qemu_put_sbe64s(f, v);
@@ -609,14 +615,15 @@ const VMStateInfo vmstate_info_int64 = {
 
 /* 8 bit unsigned int */
 
-static int get_uint8(QEMUFile *f, void *pv, size_t size)
+static int get_uint8(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     uint8_t *v = pv;
     qemu_get_8s(f, v);
     return 0;
 }
 
-static void put_uint8(QEMUFile *f, void *pv, size_t size)
+static void put_uint8(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                      QJSON *vmdesc)
 {
     uint8_t *v = pv;
     qemu_put_8s(f, v);
@@ -630,14 +637,15 @@ const VMStateInfo vmstate_info_uint8 = {
 
 /* 16 bit unsigned int */
 
-static int get_uint16(QEMUFile *f, void *pv, size_t size)
+static int get_uint16(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     uint16_t *v = pv;
     qemu_get_be16s(f, v);
     return 0;
 }
 
-static void put_uint16(QEMUFile *f, void *pv, size_t size)
+static void put_uint16(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                       QJSON *vmdesc)
 {
     uint16_t *v = pv;
     qemu_put_be16s(f, v);
@@ -651,14 +659,15 @@ const VMStateInfo vmstate_info_uint16 = {
 
 /* 32 bit unsigned int */
 
-static int get_uint32(QEMUFile *f, void *pv, size_t size)
+static int get_uint32(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     uint32_t *v = pv;
     qemu_get_be32s(f, v);
     return 0;
 }
 
-static void put_uint32(QEMUFile *f, void *pv, size_t size)
+static void put_uint32(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                       QJSON *vmdesc)
 {
     uint32_t *v = pv;
     qemu_put_be32s(f, v);
@@ -673,7 +682,8 @@ const VMStateInfo vmstate_info_uint32 = {
 /* 32 bit uint. See that the received value is the same than the one
    in the field */
 
-static int get_uint32_equal(QEMUFile *f, void *pv, size_t size)
+static int get_uint32_equal(QEMUFile *f, void *pv, size_t size,
+                            VMStateField *field)
 {
     uint32_t *v = pv;
     uint32_t v2;
@@ -693,14 +703,15 @@ const VMStateInfo vmstate_info_uint32_equal = {
 
 /* 64 bit unsigned int */
 
-static int get_uint64(QEMUFile *f, void *pv, size_t size)
+static int get_uint64(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     uint64_t *v = pv;
     qemu_get_be64s(f, v);
     return 0;
 }
 
-static void put_uint64(QEMUFile *f, void *pv, size_t size)
+static void put_uint64(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                       QJSON *vmdesc)
 {
     uint64_t *v = pv;
     qemu_put_be64s(f, v);
@@ -715,7 +726,8 @@ const VMStateInfo vmstate_info_uint64 = {
 /* 64 bit unsigned int. See that the received value is the same than the one
    in the field */
 
-static int get_uint64_equal(QEMUFile *f, void *pv, size_t size)
+static int get_uint64_equal(QEMUFile *f, void *pv, size_t size,
+                            VMStateField *field)
 {
     uint64_t *v = pv;
     uint64_t v2;
@@ -736,7 +748,8 @@ const VMStateInfo vmstate_info_uint64_equal = {
 /* 8 bit int. See that the received value is the same than the one
    in the field */
 
-static int get_uint8_equal(QEMUFile *f, void *pv, size_t size)
+static int get_uint8_equal(QEMUFile *f, void *pv, size_t size,
+                           VMStateField *field)
 {
     uint8_t *v = pv;
     uint8_t v2;
@@ -757,7 +770,8 @@ const VMStateInfo vmstate_info_uint8_equal = {
 /* 16 bit unsigned int int. See that the received value is the same than the one
    in the field */
 
-static int get_uint16_equal(QEMUFile *f, void *pv, size_t size)
+static int get_uint16_equal(QEMUFile *f, void *pv, size_t size,
+                            VMStateField *field)
 {
     uint16_t *v = pv;
     uint16_t v2;
@@ -777,7 +791,8 @@ const VMStateInfo vmstate_info_uint16_equal = {
 
 /* floating point */
 
-static int get_float64(QEMUFile *f, void *pv, size_t size)
+static int get_float64(QEMUFile *f, void *pv, size_t size,
+                       VMStateField *field)
 {
     float64 *v = pv;
 
@@ -785,7 +800,8 @@ static int get_float64(QEMUFile *f, void *pv, size_t size)
     return 0;
 }
 
-static void put_float64(QEMUFile *f, void *pv, size_t size)
+static void put_float64(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                        QJSON *vmdesc)
 {
     uint64_t *v = pv;
 
@@ -800,7 +816,8 @@ const VMStateInfo vmstate_info_float64 = {
 
 /* CPU_DoubleU type */
 
-static int get_cpudouble(QEMUFile *f, void *pv, size_t size)
+static int get_cpudouble(QEMUFile *f, void *pv, size_t size,
+                         VMStateField *field)
 {
     CPU_DoubleU *v = pv;
     qemu_get_be32s(f, &v->l.upper);
@@ -808,7 +825,8 @@ static int get_cpudouble(QEMUFile *f, void *pv, size_t size)
     return 0;
 }
 
-static void put_cpudouble(QEMUFile *f, void *pv, size_t size)
+static void put_cpudouble(QEMUFile *f, void *pv, size_t size,
+                          VMStateField *field, QJSON *vmdesc)
 {
     CPU_DoubleU *v = pv;
     qemu_put_be32s(f, &v->l.upper);
@@ -823,14 +841,16 @@ const VMStateInfo vmstate_info_cpudouble = {
 
 /* uint8_t buffers */
 
-static int get_buffer(QEMUFile *f, void *pv, size_t size)
+static int get_buffer(QEMUFile *f, void *pv, size_t size,
+                      VMStateField *field)
 {
     uint8_t *v = pv;
     qemu_get_buffer(f, v, size);
     return 0;
 }
 
-static void put_buffer(QEMUFile *f, void *pv, size_t size)
+static void put_buffer(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                       QJSON *vmdesc)
 {
     uint8_t *v = pv;
     qemu_put_buffer(f, v, size);
@@ -845,7 +865,8 @@ const VMStateInfo vmstate_info_buffer = {
 /* unused buffers: space that was used for some fields that are
    not useful anymore */
 
-static int get_unused_buffer(QEMUFile *f, void *pv, size_t size)
+static int get_unused_buffer(QEMUFile *f, void *pv, size_t size,
+                             VMStateField *field)
 {
     uint8_t buf[1024];
     int block_len;
@@ -858,7 +879,8 @@ static int get_unused_buffer(QEMUFile *f, void *pv, size_t size)
    return 0;
 }
 
-static void put_unused_buffer(QEMUFile *f, void *pv, size_t size)
+static void put_unused_buffer(QEMUFile *f, void *pv, size_t size,
+                              VMStateField *field, QJSON *vmdesc)
 {
     static const uint8_t buf[1024];
     int block_len;
@@ -883,7 +905,7 @@ const VMStateInfo vmstate_info_unused_buffer = {
  */
 /* This is the number of 64 bit words sent over the wire */
 #define BITS_TO_U64S(nr) DIV_ROUND_UP(nr, 64)
-static int get_bitmap(QEMUFile *f, void *pv, size_t size)
+static int get_bitmap(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     unsigned long *bmp = pv;
     int i, idx = 0;
@@ -897,7 +919,8 @@ static int get_bitmap(QEMUFile *f, void *pv, size_t size)
     return 0;
 }
 
-static void put_bitmap(QEMUFile *f, void *pv, size_t size)
+static void put_bitmap(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                QJSON *vmdesc)
 {
     unsigned long *bmp = pv;
     int i, idx = 0;
diff --git a/target-alpha/machine.c b/target-alpha/machine.c
index 710b783..48e3278 100644
--- a/target-alpha/machine.c
+++ b/target-alpha/machine.c
@@ -5,14 +5,15 @@
 #include "hw/boards.h"
 #include "migration/cpu.h"
 
-static int get_fpcr(QEMUFile *f, void *opaque, size_t size)
+static int get_fpcr(QEMUFile *f, void *opaque, size_t size, VMStateField *field)
 {
     CPUAlphaState *env = opaque;
     cpu_alpha_store_fpcr(env, qemu_get_be64(f));
     return 0;
 }
 
-static void put_fpcr(QEMUFile *f, void *opaque, size_t size)
+static void put_fpcr(QEMUFile *f, void *opaque, size_t size,
+                     VMStateField *field, QJSON *vmdesc)
 {
     CPUAlphaState *env = opaque;
     qemu_put_be64(f, cpu_alpha_load_fpcr(env));
diff --git a/target-arm/machine.c b/target-arm/machine.c
index 2f45260..6815fd8 100644
--- a/target-arm/machine.c
+++ b/target-arm/machine.c
@@ -17,7 +17,8 @@ static bool vfp_needed(void *opaque)
     return arm_feature(env, ARM_FEATURE_VFP);
 }
 
-static int get_fpscr(QEMUFile *f, void *opaque, size_t size)
+static int get_fpscr(QEMUFile *f, void *opaque, size_t size,
+                     VMStateField *field)
 {
     ARMCPU *cpu = opaque;
     CPUARMState *env = &cpu->env;
@@ -27,7 +28,8 @@ static int get_fpscr(QEMUFile *f, void *opaque, size_t size)
     return 0;
 }
 
-static void put_fpscr(QEMUFile *f, void *opaque, size_t size)
+static void put_fpscr(QEMUFile *f, void *opaque, size_t size,
+                      VMStateField *field, QJSON *vmdesc)
 {
     ARMCPU *cpu = opaque;
     CPUARMState *env = &cpu->env;
@@ -163,7 +165,8 @@ static const VMStateDescription vmstate_pmsav7 = {
     }
 };
 
-static int get_cpsr(QEMUFile *f, void *opaque, size_t size)
+static int get_cpsr(QEMUFile *f, void *opaque, size_t size,
+                    VMStateField *field)
 {
     ARMCPU *cpu = opaque;
     CPUARMState *env = &cpu->env;
@@ -180,7 +183,8 @@ static int get_cpsr(QEMUFile *f, void *opaque, size_t size)
     return 0;
 }
 
-static void put_cpsr(QEMUFile *f, void *opaque, size_t size)
+static void put_cpsr(QEMUFile *f, void *opaque, size_t size,
+                     VMStateField *field, QJSON *vmdesc)
 {
     ARMCPU *cpu = opaque;
     CPUARMState *env = &cpu->env;
diff --git a/target-i386/machine.c b/target-i386/machine.c
index cb9adf2..e5279e7 100644
--- a/target-i386/machine.c
+++ b/target-i386/machine.c
@@ -139,7 +139,8 @@ static const VMStateDescription vmstate_mtrr_var = {
 #define VMSTATE_MTRR_VARS(_field, _state, _n, _v)                    \
     VMSTATE_STRUCT_ARRAY(_field, _state, _n, _v, vmstate_mtrr_var, MTRRVar)
 
-static void put_fpreg_error(QEMUFile *f, void *opaque, size_t size)
+static void put_fpreg_error(QEMUFile *f, void *opaque, size_t size,
+                            VMStateField *field, QJSON *vmdesc)
 {
     fprintf(stderr, "call put_fpreg() with invalid arguments\n");
     exit(0);
@@ -167,7 +168,8 @@ static void fp64_to_fp80(union x86_longdouble *p, uint64_t temp)
     p->exp = e;
 }
 
-static int get_fpreg(QEMUFile *f, void *opaque, size_t size)
+static int get_fpreg(QEMUFile *f, void *opaque, size_t size,
+                     VMStateField *field)
 {
     FPReg *fp_reg = opaque;
     uint64_t mant;
@@ -179,7 +181,8 @@ static int get_fpreg(QEMUFile *f, void *opaque, size_t size)
     return 0;
 }
 
-static void put_fpreg(QEMUFile *f, void *opaque, size_t size)
+static void put_fpreg(QEMUFile *f, void *opaque, size_t size,
+                      VMStateField *field, QJSON *vmdesc)
 {
     FPReg *fp_reg = opaque;
     uint64_t mant;
@@ -197,7 +200,8 @@ static const VMStateInfo vmstate_fpreg = {
     .put  = put_fpreg,
 };
 
-static int get_fpreg_1_mmx(QEMUFile *f, void *opaque, size_t size)
+static int get_fpreg_1_mmx(QEMUFile *f, void *opaque, size_t size,
+                           VMStateField *field)
 {
     union x86_longdouble *p = opaque;
     uint64_t mant;
@@ -214,7 +218,8 @@ static const VMStateInfo vmstate_fpreg_1_mmx = {
     .put  = put_fpreg_error,
 };
 
-static int get_fpreg_1_no_mmx(QEMUFile *f, void *opaque, size_t size)
+static int get_fpreg_1_no_mmx(QEMUFile *f, void *opaque, size_t size,
+                              VMStateField *field)
 {
     union x86_longdouble *p = opaque;
     uint64_t mant;
@@ -276,14 +281,16 @@ static bool less_than_7(void *opaque, int version_id)
     return version_id < 7;
 }
 
-static int get_uint64_as_uint32(QEMUFile *f, void *pv, size_t size)
+static int get_uint64_as_uint32(QEMUFile *f, void *pv, size_t size,
+                                VMStateField *field)
 {
     uint64_t *v = pv;
     *v = qemu_get_be32(f);
     return 0;
 }
 
-static void put_uint64_as_uint32(QEMUFile *f, void *pv, size_t size)
+static void put_uint64_as_uint32(QEMUFile *f, void *pv, size_t size,
+                                 VMStateField *field, QJSON *vmdesc)
 {
     uint64_t *v = pv;
     qemu_put_be32(f, *v);
diff --git a/target-mips/machine.c b/target-mips/machine.c
index 7314cfe..ebc984e 100644
--- a/target-mips/machine.c
+++ b/target-mips/machine.c
@@ -20,7 +20,7 @@ static int cpu_post_load(void *opaque, int version_id)
 
 /* FPU state */
 
-static int get_fpr(QEMUFile *f, void *pv, size_t size)
+static int get_fpr(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     int i;
     fpr_t *v = pv;
@@ -31,7 +31,8 @@ static int get_fpr(QEMUFile *f, void *pv, size_t size)
     return 0;
 }
 
-static void put_fpr(QEMUFile *f, void *pv, size_t size)
+static void put_fpr(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                    QJSON *vmdesc)
 {
     int i;
     fpr_t *v = pv;
@@ -125,7 +126,7 @@ const VMStateDescription vmstate_mvp = {
 
 /* TLB state */
 
-static int get_tlb(QEMUFile *f, void *pv, size_t size)
+static int get_tlb(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     r4k_tlb_t *v = pv;
     uint16_t flags;
@@ -152,7 +153,8 @@ static int get_tlb(QEMUFile *f, void *pv, size_t size)
     return 0;
 }
 
-static void put_tlb(QEMUFile *f, void *pv, size_t size)
+static void put_tlb(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                    QJSON *vmdesc)
 {
     r4k_tlb_t *v = pv;
 
diff --git a/target-ppc/machine.c b/target-ppc/machine.c
index 4820f22..0e1822c 100644
--- a/target-ppc/machine.c
+++ b/target-ppc/machine.c
@@ -106,7 +106,7 @@ static int cpu_load_old(QEMUFile *f, void *opaque, int version_id)
     return 0;
 }
 
-static int get_avr(QEMUFile *f, void *pv, size_t size)
+static int get_avr(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     ppc_avr_t *v = pv;
 
@@ -116,7 +116,8 @@ static int get_avr(QEMUFile *f, void *pv, size_t size)
     return 0;
 }
 
-static void put_avr(QEMUFile *f, void *pv, size_t size)
+static void put_avr(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                    QJSON *vmdesc)
 {
     ppc_avr_t *v = pv;
 
@@ -324,7 +325,7 @@ static const VMStateDescription vmstate_sr = {
 };
 
 #ifdef TARGET_PPC64
-static int get_slbe(QEMUFile *f, void *pv, size_t size)
+static int get_slbe(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     ppc_slb_t *v = pv;
 
@@ -334,7 +335,8 @@ static int get_slbe(QEMUFile *f, void *pv, size_t size)
     return 0;
 }
 
-static void put_slbe(QEMUFile *f, void *pv, size_t size)
+static void put_slbe(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                     QJSON *vmdesc)
 {
     ppc_slb_t *v = pv;
 
diff --git a/target-sparc/machine.c b/target-sparc/machine.c
index 59c92f7..3194e03 100644
--- a/target-sparc/machine.c
+++ b/target-sparc/machine.c
@@ -59,7 +59,7 @@ static const VMStateDescription vmstate_tlb_entry = {
 };
 #endif
 
-static int get_psr(QEMUFile *f, void *opaque, size_t size)
+static int get_psr(QEMUFile *f, void *opaque, size_t size, VMStateField *field)
 {
     SPARCCPU *cpu = opaque;
     CPUSPARCState *env = &cpu->env;
@@ -72,7 +72,8 @@ static int get_psr(QEMUFile *f, void *opaque, size_t size)
     return 0;
 }
 
-static void put_psr(QEMUFile *f, void *opaque, size_t size)
+static void put_psr(QEMUFile *f, void *opaque, size_t size, VMStateField *field,
+                QJSON *vmdesc)
 {
     SPARCCPU *cpu = opaque;
     CPUSPARCState *env = &cpu->env;
-- 
1.9.1

[Qemu-devel] [QEMU PATCH v4 4/6] migration: migrate QTAILQ

[Jianjun Duan]

Currently we cannot directly transfer a QTAILQ instance because of the
limitation in the migration code. Here we introduce an approach to
transfer such structures. In our approach such a structure is tagged
with VMS_LINKED. We then modified vmstate_save_state and vmstate_load_state
so that when VMS_LINKED is encountered, put and get from VMStateInfo are
called respectively. We created VMStateInfo vmstate_info_qtailq for QTAILQ.
Similar VMStateInfo can be created for other data structures such as list.
This approach will be used to transfer pending_events and ccs_list in spapr
state.

We also create some macros in qemu/queue.h to access a QTAILQ using pointer
arithmetic. This ensures that we do not depend on the implementation
details about QTAILQ in the migration code.

Signed-off-by: Jianjun Duan <duanj@linux.vnet.ibm.com>
---
 include/migration/vmstate.h | 26 ++++++++++++++++++
 include/qemu/queue.h        | 32 ++++++++++++++++++++++
 migration/vmstate.c         | 66 +++++++++++++++++++++++++++++++++++++++++++++
 trace-events                |  4 +++
 4 files changed, 128 insertions(+)

diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index 56a4171..bce911f 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -185,6 +185,12 @@ enum VMStateFlags {
      * to determine the number of entries in the array. Only valid in
      * combination with one of VMS_VARRAY*. */
     VMS_MULTIPLY_ELEMENTS = 0x4000,
+    /* For fields which need customized handling, such as QTAILQ in queue.h.
+     * When this flag is set in VMStateField, info->get/put will
+     * be used in vmstate_load/save_state instead of recursive call.
+     * User should implement set info to handle the concerned data structure.
+     */
+    VMS_LINKED            = 0x8000,
 };
 
 struct VMStateField {
@@ -245,6 +251,7 @@ extern const VMStateInfo vmstate_info_timer;
 extern const VMStateInfo vmstate_info_buffer;
 extern const VMStateInfo vmstate_info_unused_buffer;
 extern const VMStateInfo vmstate_info_bitmap;
+extern const VMStateInfo vmstate_info_qtailq;
 
 #define type_check_2darray(t1,t2,n,m) ((t1(*)[n][m])0 - (t2*)0)
 #define type_check_array(t1,t2,n) ((t1(*)[n])0 - (t2*)0)
@@ -656,6 +663,25 @@ extern const VMStateInfo vmstate_info_bitmap;
     .offset       = offsetof(_state, _field),                        \
 }
 
+/* For QTAILQ that need customized handling
+ * _type: type of QTAILQ element
+ * _next: name of QTAILQ entry field in QTAILQ element
+ * _vmsd: VMSD for QTAILQ element
+ * size: size of QTAILQ element
+ * start: offset of QTAILQ entry in QTAILQ element
+ */
+#define VMSTATE_QTAILQ_V(_field, _state, _version, _vmsd, _type, _next)  \
+{                                                                        \
+    .name         = (stringify(_field)),                                 \
+    .version_id   = (_version),                                          \
+    .vmsd         = &(_vmsd),                                            \
+    .size         = sizeof(_type),                                       \
+    .info         = &vmstate_info_qtailq,                                \
+    .flags        = VMS_LINKED,                                          \
+    .offset       = offsetof(_state, _field),                            \
+    .start        = offsetof(_type, _next),                              \
+}
+
 /* _f : field name
    _f_n : num of elements field_name
    _n : num of elements
diff --git a/include/qemu/queue.h b/include/qemu/queue.h
index f781aa2..003e368 100644
--- a/include/qemu/queue.h
+++ b/include/qemu/queue.h
@@ -437,3 +437,35 @@ struct {                                                                \
         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 
 #endif  /* !QEMU_SYS_QUEUE_H_ */
+
+/*
+ * Offsets of layout of a tail queue head.
+ */
+#define QTAILQ_FIRST_OFFSET 0
+#define QTAILQ_LAST_OFFSET (sizeof(void *))
+
+/*
+ * Offsets of layout of a tail queue element.
+ */
+#define QTAILQ_NEXT_OFFSET 0
+#define QTAILQ_PREV_OFFSET (sizeof(void *))
+
+/*
+ * Tail queue tranversal using pointer arithmetic.
+ */
+#define QTAILQ_RAW_FOREACH(elm, head, entry)                                   \
+        for ((elm) = *((void **) ((char *) (head) + QTAILQ_FIRST_OFFSET));     \
+             (elm);                                                            \
+             (elm) =                                                           \
+                 *((void **) ((char *) (elm) + (entry) + QTAILQ_NEXT_OFFSET)))
+/*
+ * Tail queue insertion using pointer arithmetic.
+ */
+#define QTAILQ_RAW_INSERT_TAIL(head, elm, entry) do {                          \
+        *((void **) ((char *) (elm) + (entry) + QTAILQ_NEXT_OFFSET)) = NULL;   \
+        *((void **) ((char *) (elm) + (entry) + QTAILQ_PREV_OFFSET)) =         \
+            *((void **) ((char *) (head) +QTAILQ_LAST_OFFSET));                \
+        **((void ***)((char *) (head) +QTAILQ_LAST_OFFSET)) = (elm);           \
+        *((void **) ((char *) (head) + QTAILQ_LAST_OFFSET)) =                  \
+            (void *) ((char *) (elm) + (entry) + QTAILQ_NEXT_OFFSET);          \
+} while (/*CONSTCOND*/0)
diff --git a/migration/vmstate.c b/migration/vmstate.c
index 644ba1f..177a786 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -5,7 +5,9 @@
 #include "migration/vmstate.h"
 #include "qemu/bitops.h"
 #include "qemu/error-report.h"
+#include "qemu/queue.h"
 #include "trace.h"
+#include "migration/qjson.h"
 
 static void vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
                                     void *opaque, QJSON *vmdesc);
@@ -120,6 +122,8 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
                 if (field->flags & VMS_STRUCT) {
                     ret = vmstate_load_state(f, field->vmsd, addr,
                                              field->vmsd->version_id);
+                } else if (field->flags & VMS_LINKED) {
+                    ret = field->info->get(f, addr, size, field);
                 } else {
                     ret = field->info->get(f, addr, size, NULL);
 
@@ -192,6 +196,8 @@ static const char *vmfield_get_type_name(VMStateField *field)
 
     if (field->flags & VMS_STRUCT) {
         type = "struct";
+    } else if (field->flags & VMS_LINKED) {
+        type = "linked";
     } else if (field->info->name) {
         type = field->info->name;
     }
@@ -326,6 +332,8 @@ void vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
                 }
                 if (field->flags & VMS_STRUCT) {
                     vmstate_save_state(f, field->vmsd, addr, vmdesc_loop);
+                } else if  (field->flags & VMS_LINKED) {
+                    field->info->put(f, addr, size, field, vmdesc_loop);
                 } else {
                     field->info->put(f, addr, size, NULL, NULL);
                 }
@@ -938,3 +946,61 @@ const VMStateInfo vmstate_info_bitmap = {
     .get = get_bitmap,
     .put = put_bitmap,
 };
+
+/*get for QTAILQ */
+static int get_qtailq(QEMUFile *f, void *pv, size_t unused_size,
+                      VMStateField *field)
+{
+    int ret = 0;
+    const VMStateDescription *vmsd = field->vmsd;
+    size_t size = field->size;
+    size_t entry = field->start;
+    int version_id = field->version_id;
+    void *elm;
+
+    trace_get_qtailq(vmsd->name, version_id);
+    if (version_id > vmsd->version_id) {
+        trace_get_qtailq_end(vmsd->name, "too new", -EINVAL);
+        return -EINVAL;
+    }
+    if (version_id < vmsd->minimum_version_id) {
+        trace_get_qtailq_end(vmsd->name, "too old", -EINVAL);
+        return -EINVAL;
+    }
+
+    while (qemu_get_byte(f)) {
+        elm =  g_malloc(size);
+        ret = vmstate_load_state(f, vmsd, elm, version_id);
+        if (ret) {
+            return ret;
+        }
+        QTAILQ_RAW_INSERT_TAIL(pv, elm, entry);
+    }
+
+    trace_get_qtailq_end(vmsd->name, "end", ret);
+    return ret;
+}
+
+/* put for QTAILQ */
+static void put_qtailq(QEMUFile *f, void *pv, size_t unused_size,
+                       VMStateField *field, QJSON *vmdesc)
+{
+    const VMStateDescription *vmsd = field->vmsd;
+    size_t entry = field->start;
+    void *elm;
+
+    trace_put_qtailq(vmsd->name, vmsd->version_id);
+
+    QTAILQ_RAW_FOREACH(elm, pv, entry) {
+        qemu_put_byte(f, true);
+        vmstate_save_state(f, vmsd, elm, vmdesc);
+    }
+    qemu_put_byte(f, false);
+
+    trace_put_qtailq_end(vmsd->name, "end");
+}
+const VMStateInfo vmstate_info_qtailq = {
+    .name = "qtailq",
+    .get  = get_qtailq,
+    .put  = put_qtailq,
+};
diff --git a/trace-events b/trace-events
index 75777ed..3dbcc89 100644
--- a/trace-events
+++ b/trace-events
@@ -1273,6 +1273,10 @@ vmstate_load_state_field(const char *name, const char *field) "%s:%s"
 vmstate_subsection_load(const char *parent) "%s"
 vmstate_subsection_load_bad(const char *parent,  const char *sub) "%s: %s"
 vmstate_subsection_load_good(const char *parent) "%s"
+get_qtailq(const char *name, int version_id) "%s v%d"
+get_qtailq_end(const char *name, const char *reason, int val) "%s %s/%d"
+put_qtailq(const char *name, int version_id) "%s v%d"
+put_qtailq_end(const char *name, const char *reason) "%s %s"
 
 # qemu-file.c
 qemu_file_fclose(void) ""
-- 
1.9.1

[Qemu-devel] [QEMU PATCH v4 5/6] migration: spapr: migrate ccs_list in spapr state

[Jianjun Duan]

ccs_list in spapr state maintains the device tree related
information on the rtas side for hotplugged devices. In racing
situations between hotplug events and migration operation, a rtas
hotplug event could be migrated from the source guest to target
guest, or the source guest could have not yet finished fetching
the device tree when migration is started, the target will try
to finish fetching the device tree. By migrating ccs_list, the
target can fetch the device tree properly.

ccs_list is put in a subsection in the spapr state VMSD to make
sure migration across different versions is not broken.

Signed-off-by: Jianjun Duan <duanj@linux.vnet.ibm.com>
---
 hw/ppc/spapr.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 0636642..54a8af6 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1266,6 +1266,36 @@ static bool version_before_3(void *opaque, int version_id)
     return version_id < 3;
 }
 
+static bool spapr_ccs_list_needed(void *opaque)
+{
+    sPAPRMachineState *spapr = (sPAPRMachineState *)opaque;
+    return !QTAILQ_EMPTY(&spapr->ccs_list);
+}
+
+static const VMStateDescription vmstate_spapr_ccs = {
+    .name = "spaprconfigureconnectorstate",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(drc_index, sPAPRConfigureConnectorState),
+        VMSTATE_INT32(fdt_offset, sPAPRConfigureConnectorState),
+        VMSTATE_INT32(fdt_depth, sPAPRConfigureConnectorState),
+        VMSTATE_END_OF_LIST()
+    },
+};
+
+static const VMStateDescription vmstate_spapr_ccs_list = {
+    .name = "spaprccslist",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = spapr_ccs_list_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_QTAILQ_V(ccs_list, sPAPRMachineState, 1,
+                         vmstate_spapr_ccs, sPAPRConfigureConnectorState, next),
+        VMSTATE_END_OF_LIST()
+    },
+};
+
 static const VMStateDescription vmstate_spapr = {
     .name = "spapr",
     .version_id = 3,
@@ -1281,6 +1311,10 @@ static const VMStateDescription vmstate_spapr = {
         VMSTATE_PPC_TIMEBASE_V(tb, sPAPRMachineState, 2),
         VMSTATE_END_OF_LIST()
     },
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_spapr_ccs_list,
+        NULL
+    }
 };
 
 static int htab_save_setup(QEMUFile *f, void *opaque)
-- 
1.9.1

[Qemu-devel] [QEMU PATCH v4 6/6] migration: spapr: migrate pending_events of spapr state

[Jianjun Duan]

In racing situations between hotplug events and migration operation,
a rtas hotplug event could have not yet be delivered to the source
guest when migration is started. In this case the pending_events of
spapr state need be transmitted to the target so that the hotplug
event can be finished on the target.

All the different fields of the events are encoded as defined by
PAPR. We can migrate them as uint8_t binary stream without any
concerns about data padding or endianess.

pending_events is put in a subsection in the spapr state VMSD to make
sure migration across different versions is not broken.

Signed-off-by: Jianjun Duan <duanj@linux.vnet.ibm.com>
---
 hw/ppc/spapr.c         | 33 +++++++++++++++++++++++++++++++++
 hw/ppc/spapr_events.c  | 22 +++++++++++++---------
 include/hw/ppc/spapr.h |  3 ++-
 3 files changed, 48 insertions(+), 10 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 54a8af6..ecff138 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1266,12 +1266,32 @@ static bool version_before_3(void *opaque, int version_id)
     return version_id < 3;
 }
 
+static bool spapr_pending_events_needed(void *opaque)
+{
+    sPAPRMachineState *spapr = (sPAPRMachineState *)opaque;
+    return !QTAILQ_EMPTY(&spapr->pending_events);
+}
+
 static bool spapr_ccs_list_needed(void *opaque)
 {
     sPAPRMachineState *spapr = (sPAPRMachineState *)opaque;
     return !QTAILQ_EMPTY(&spapr->ccs_list);
 }
 
+static const VMStateDescription vmstate_spapr_event_entry = {
+    .name = "spapreventlogentry",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_INT32(log_type, sPAPREventLogEntry),
+        VMSTATE_BOOL(exception, sPAPREventLogEntry),
+        VMSTATE_UINT32(data_size, sPAPREventLogEntry),
+        VMSTATE_VARRAY_UINT32_ALLOC(data, sPAPREventLogEntry, data_size,
+                                    0, vmstate_info_uint8, uint8_t),
+        VMSTATE_END_OF_LIST()
+  },
+};
+
 static const VMStateDescription vmstate_spapr_ccs = {
     .name = "spaprconfigureconnectorstate",
     .version_id = 1,
@@ -1284,6 +1304,18 @@ static const VMStateDescription vmstate_spapr_ccs = {
     },
 };
 
+static const VMStateDescription vmstate_spapr_pending_events = {
+    .name = "spaprpendingevents",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = spapr_pending_events_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_QTAILQ_V(pending_events, sPAPRMachineState, 1,
+                         vmstate_spapr_event_entry, sPAPREventLogEntry, next),
+        VMSTATE_END_OF_LIST()
+    },
+};
+
 static const VMStateDescription vmstate_spapr_ccs_list = {
     .name = "spaprccslist",
     .version_id = 1,
@@ -1312,6 +1344,7 @@ static const VMStateDescription vmstate_spapr = {
         VMSTATE_END_OF_LIST()
     },
     .subsections = (const VMStateDescription*[]) {
+        &vmstate_spapr_pending_events,
         &vmstate_spapr_ccs_list,
         NULL
     }
diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
index 049fb1b..1680c08 100644
--- a/hw/ppc/spapr_events.c
+++ b/hw/ppc/spapr_events.c
@@ -239,7 +239,8 @@ void spapr_events_fdt_skel(void *fdt, uint32_t check_exception_irq)
     _FDT((fdt_end_node(fdt)));
 }
 
-static void rtas_event_log_queue(int log_type, void *data, bool exception)
+static void rtas_event_log_queue(int log_type, void *data, bool exception,
+				 int data_size)
 {
     sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
     sPAPREventLogEntry *entry = g_new(sPAPREventLogEntry, 1);
@@ -248,6 +249,7 @@ static void rtas_event_log_queue(int log_type, void *data, bool exception)
     entry->log_type = log_type;
     entry->exception = exception;
     entry->data = data;
+    entry->data_size = data_size;
     QTAILQ_INSERT_TAIL(&spapr->pending_events, entry, next);
 }
 
@@ -350,6 +352,7 @@ static void spapr_powerdown_req(Notifier *n, void *opaque)
     struct rtas_event_log_v6_mainb *mainb;
     struct rtas_event_log_v6_epow *epow;
     struct epow_log_full *new_epow;
+    uint32_t data_size;
 
     new_epow = g_malloc0(sizeof(*new_epow));
     hdr = &new_epow->hdr;
@@ -358,13 +361,13 @@ static void spapr_powerdown_req(Notifier *n, void *opaque)
     mainb = &new_epow->mainb;
     epow = &new_epow->epow;
 
+    data_size = sizeof(*new_epow);
     hdr->summary = cpu_to_be32(RTAS_LOG_VERSION_6
                                | RTAS_LOG_SEVERITY_EVENT
                                | RTAS_LOG_DISPOSITION_NOT_RECOVERED
                                | RTAS_LOG_OPTIONAL_PART_PRESENT
                                | RTAS_LOG_TYPE_EPOW);
-    hdr->extended_length = cpu_to_be32(sizeof(*new_epow)
-                                       - sizeof(new_epow->hdr));
+    hdr->extended_length = cpu_to_be32(data_size - sizeof(new_epow->hdr));
 
     spapr_init_v6hdr(v6hdr);
     spapr_init_maina(maina, 3 /* Main-A, Main-B and EPOW */);
@@ -384,7 +387,7 @@ static void spapr_powerdown_req(Notifier *n, void *opaque)
     epow->event_modifier = RTAS_LOG_V6_EPOW_MODIFIER_NORMAL;
     epow->extended_modifier = RTAS_LOG_V6_EPOW_XMODIFIER_PARTITION_SPECIFIC;
 
-    rtas_event_log_queue(RTAS_LOG_TYPE_EPOW, new_epow, true);
+    rtas_event_log_queue(RTAS_LOG_TYPE_EPOW, new_epow, true, data_size);
 
     qemu_irq_pulse(xics_get_qirq(spapr->icp, spapr->check_exception_irq));
 }
@@ -407,6 +410,7 @@ static void spapr_hotplug_req_event(uint8_t hp_id, uint8_t hp_action,
     struct rtas_event_log_v6_maina *maina;
     struct rtas_event_log_v6_mainb *mainb;
     struct rtas_event_log_v6_hp *hp;
+    uint32_t data_size;
 
     new_hp = g_malloc0(sizeof(struct hp_log_full));
     hdr = &new_hp->hdr;
@@ -415,14 +419,14 @@ static void spapr_hotplug_req_event(uint8_t hp_id, uint8_t hp_action,
     mainb = &new_hp->mainb;
     hp = &new_hp->hp;
 
+    data_size = sizeof(*new_hp);
     hdr->summary = cpu_to_be32(RTAS_LOG_VERSION_6
                                | RTAS_LOG_SEVERITY_EVENT
                                | RTAS_LOG_DISPOSITION_NOT_RECOVERED
                                | RTAS_LOG_OPTIONAL_PART_PRESENT
                                | RTAS_LOG_INITIATOR_HOTPLUG
                                | RTAS_LOG_TYPE_HOTPLUG);
-    hdr->extended_length = cpu_to_be32(sizeof(*new_hp)
-                                       - sizeof(new_hp->hdr));
+    hdr->extended_length = cpu_to_be32(data_size - sizeof(new_hp->hdr));
 
     spapr_init_v6hdr(v6hdr);
     spapr_init_maina(maina, 3 /* Main-A, Main-B, HP */);
@@ -463,7 +467,7 @@ static void spapr_hotplug_req_event(uint8_t hp_id, uint8_t hp_action,
         hp->drc.index = cpu_to_be32(drc);
     }
 
-    rtas_event_log_queue(RTAS_LOG_TYPE_HOTPLUG, new_hp, true);
+    rtas_event_log_queue(RTAS_LOG_TYPE_HOTPLUG, new_hp, true, data_size);
 
     qemu_irq_pulse(xics_get_qirq(spapr->icp, spapr->check_exception_irq));
 }
@@ -530,7 +534,7 @@ static void check_exception(PowerPCCPU *cpu, sPAPRMachineState *spapr,
         goto out_no_events;
     }
 
-    hdr = event->data;
+    hdr = (struct rtas_error_log *)event->data;
     event_len = be32_to_cpu(hdr->extended_length) + sizeof(*hdr);
 
     if (event_len < len) {
@@ -580,7 +584,7 @@ static void event_scan(PowerPCCPU *cpu, sPAPRMachineState *spapr,
         goto out_no_events;
     }
 
-    hdr = event->data;
+    hdr = (struct rtas_error_log *)event->data;
     event_len = be32_to_cpu(hdr->extended_length) + sizeof(*hdr);
 
     if (event_len < len) {
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 971df3d..965bd3e 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -554,7 +554,8 @@ sPAPRTCETable *spapr_tce_find_by_liobn(target_ulong liobn);
 struct sPAPREventLogEntry {
     int log_type;
     bool exception;
-    void *data;
+    uint32_t data_size;
+    uint8_t *data;
     QTAILQ_ENTRY(sPAPREventLogEntry) next;
 };
 
-- 
1.9.1

Re: [Qemu-devel] [QEMU PATCH v4 0/6] migration: ensure hotplug and migration work together

[Amit Shah]

Hi,

I'm going to go through this series soon, and I know Dave is too.
Please give us some time to go through it.

Thanks,

On (Mon) 27 Jun 2016 [09:59:58], Jianjun Duan wrote:
> Hi all,
>    The previous patches seem to get buried deep somewhere. I am resending them
>  without RFC tag. Comments are welcome.
> 
> v4: - Introduce a way to set customized instance_id in SaveStateEntry. Use it
>       to set instance_id for DRC using its unique index to address David 
>       Gibson's concern.
>     - Rename VMS_CSTM to VMS_LINKED based on Paolo Bonzini's suggestions.
>     - Clean up qjson stuff in put_qtailq. 
>     - Add trace for put_qtailq and get_qtailq based on David Gilbert's 
>       suggestion.
> 
> It is based on David's ppc-for-2.7. Comments are welcome. Previous versions are:
> 
> v3: - Simplify overall design followng discussion with Paolo. No longer need
>       metadata to migrate QTAILQ.
>     - Extend VMStateInfo instead of adding similar fields to VMStateField.
>     - Clean up macros in qemu/queue.h.
> (link: https://lists.nongnu.org/archive/html/qemu-devel/2016-05/msg05695.html)
> 
> v2: - Introduce a general approach to migrate QTAILQ in qemu/queue.h.
>     - Migrate signalled field in the DRC state.
>     - Put the newly added migrating fields in subsections so that backward 
>       migration is not broken.  
>     - Set detach_cb field right after migration so that a migrated hot-unplug
>       event could finish its course.
> (link: https://lists.nongnu.org/archive/html/qemu-devel/2016-05/msg04188.html)
> 
> v1: - Inital version.
> (link: https://lists.nongnu.org/archive/html/qemu-devel/2016-04/msg02601.html)
> 
> To make guest device (PCI, CPU and memory) hotplug work together 
> with guest migration, spapr drc state needs be transmitted in
> migration. This patch defines the VMStateDescription struct for
> spapr drc state to enable it.
> 
> To fix the potential racing between hotplug events on guest and 
> guest migration, ccs_list and pending_events of spapr state need be 
> transmitted in migration. This patch also takes care of it.
> 
> Jianjun Duan (6):
>   migration: alternative way to set instance_id in SaveStateEntry
>   migration: spapr_drc: defined VMStateDescription struct
>   migration: extend VMStateInfo
>   migration: migrate QTAILQ
>   migration: spapr: migrate ccs_list in spapr state
>   migration: spapr: migrate pending_events of spapr state
> 
>  hw/net/vmxnet3.c            |  18 +++--
>  hw/nvram/eeprom93xx.c       |   6 +-
>  hw/nvram/fw_cfg.c           |   6 +-
>  hw/pci/msix.c               |   6 +-
>  hw/pci/pci.c                |  12 ++--
>  hw/pci/shpc.c               |   5 +-
>  hw/ppc/spapr.c              |  67 ++++++++++++++++++
>  hw/ppc/spapr_drc.c          |  69 +++++++++++++++++++
>  hw/ppc/spapr_events.c       |  22 +++---
>  hw/ppc/spapr_pci.c          |  22 ++++++
>  hw/scsi/scsi-bus.c          |   6 +-
>  hw/timer/twl92230.c         |   6 +-
>  hw/usb/redirect.c           |  18 +++--
>  hw/virtio/virtio-pci.c      |   6 +-
>  hw/virtio/virtio.c          |   6 +-
>  include/hw/ppc/spapr.h      |   3 +-
>  include/hw/ppc/spapr_drc.h  |   9 +++
>  include/hw/qdev-core.h      |   6 ++
>  include/migration/vmstate.h |  36 ++++++++--
>  include/qemu/queue.h        |  32 +++++++++
>  migration/savevm.c          |  25 +++++--
>  migration/vmstate.c         | 161 ++++++++++++++++++++++++++++++++++----------
>  target-alpha/machine.c      |   5 +-
>  target-arm/machine.c        |  12 ++--
>  target-i386/machine.c       |  21 ++++--
>  target-mips/machine.c       |  10 +--
>  target-ppc/machine.c        |  10 +--
>  target-sparc/machine.c      |   5 +-
>  trace-events                |   4 ++
>  29 files changed, 505 insertions(+), 109 deletions(-)
> 
> -- 
> 1.9.1
> 

		Amit

Re: [Qemu-devel] [QEMU PATCH v4 0/6] migration: ensure hotplug and migration work together

[Jianjun Duan]

Hi Amit,
    Have you had a chance to take a look?

Thanks,
Jianjun
On 07/08/2016 03:18 AM, Amit Shah wrote:
> Hi,
> 
> I'm going to go through this series soon, and I know Dave is too.
> Please give us some time to go through it.
> 
> Thanks,
> 
> On (Mon) 27 Jun 2016 [09:59:58], Jianjun Duan wrote:
>> Hi all,
>>    The previous patches seem to get buried deep somewhere. I am resending them
>>  without RFC tag. Comments are welcome.
>>
>> v4: - Introduce a way to set customized instance_id in SaveStateEntry. Use it
>>       to set instance_id for DRC using its unique index to address David 
>>       Gibson's concern.
>>     - Rename VMS_CSTM to VMS_LINKED based on Paolo Bonzini's suggestions.
>>     - Clean up qjson stuff in put_qtailq. 
>>     - Add trace for put_qtailq and get_qtailq based on David Gilbert's 
>>       suggestion.
>>
>> It is based on David's ppc-for-2.7. Comments are welcome. Previous versions are:
>>
>> v3: - Simplify overall design followng discussion with Paolo. No longer need
>>       metadata to migrate QTAILQ.
>>     - Extend VMStateInfo instead of adding similar fields to VMStateField.
>>     - Clean up macros in qemu/queue.h.
>> (link: https://lists.nongnu.org/archive/html/qemu-devel/2016-05/msg05695.html)
>>
>> v2: - Introduce a general approach to migrate QTAILQ in qemu/queue.h.
>>     - Migrate signalled field in the DRC state.
>>     - Put the newly added migrating fields in subsections so that backward 
>>       migration is not broken.  
>>     - Set detach_cb field right after migration so that a migrated hot-unplug
>>       event could finish its course.
>> (link: https://lists.nongnu.org/archive/html/qemu-devel/2016-05/msg04188.html)
>>
>> v1: - Inital version.
>> (link: https://lists.nongnu.org/archive/html/qemu-devel/2016-04/msg02601.html)
>>
>> To make guest device (PCI, CPU and memory) hotplug work together 
>> with guest migration, spapr drc state needs be transmitted in
>> migration. This patch defines the VMStateDescription struct for
>> spapr drc state to enable it.
>>
>> To fix the potential racing between hotplug events on guest and 
>> guest migration, ccs_list and pending_events of spapr state need be 
>> transmitted in migration. This patch also takes care of it.
>>
>> Jianjun Duan (6):
>>   migration: alternative way to set instance_id in SaveStateEntry
>>   migration: spapr_drc: defined VMStateDescription struct
>>   migration: extend VMStateInfo
>>   migration: migrate QTAILQ
>>   migration: spapr: migrate ccs_list in spapr state
>>   migration: spapr: migrate pending_events of spapr state
>>
>>  hw/net/vmxnet3.c            |  18 +++--
>>  hw/nvram/eeprom93xx.c       |   6 +-
>>  hw/nvram/fw_cfg.c           |   6 +-
>>  hw/pci/msix.c               |   6 +-
>>  hw/pci/pci.c                |  12 ++--
>>  hw/pci/shpc.c               |   5 +-
>>  hw/ppc/spapr.c              |  67 ++++++++++++++++++
>>  hw/ppc/spapr_drc.c          |  69 +++++++++++++++++++
>>  hw/ppc/spapr_events.c       |  22 +++---
>>  hw/ppc/spapr_pci.c          |  22 ++++++
>>  hw/scsi/scsi-bus.c          |   6 +-
>>  hw/timer/twl92230.c         |   6 +-
>>  hw/usb/redirect.c           |  18 +++--
>>  hw/virtio/virtio-pci.c      |   6 +-
>>  hw/virtio/virtio.c          |   6 +-
>>  include/hw/ppc/spapr.h      |   3 +-
>>  include/hw/ppc/spapr_drc.h  |   9 +++
>>  include/hw/qdev-core.h      |   6 ++
>>  include/migration/vmstate.h |  36 ++++++++--
>>  include/qemu/queue.h        |  32 +++++++++
>>  migration/savevm.c          |  25 +++++--
>>  migration/vmstate.c         | 161 ++++++++++++++++++++++++++++++++++----------
>>  target-alpha/machine.c      |   5 +-
>>  target-arm/machine.c        |  12 ++--
>>  target-i386/machine.c       |  21 ++++--
>>  target-mips/machine.c       |  10 +--
>>  target-ppc/machine.c        |  10 +--
>>  target-sparc/machine.c      |   5 +-
>>  trace-events                |   4 ++
>>  29 files changed, 505 insertions(+), 109 deletions(-)
>>
>> -- 
>> 1.9.1
>>
> 
> 		Amit
> 

Re: [Qemu-devel] [Qemu-ppc] [QEMU PATCH v4 0/6] migration: ensure hotplug and migration work together

[Jianjun Duan]

ping

On 06/27/2016 09:59 AM, Jianjun Duan wrote:
> Hi all,
>    The previous patches seem to get buried deep somewhere. I am resending them
>  without RFC tag. Comments are welcome.
> 
> v4: - Introduce a way to set customized instance_id in SaveStateEntry. Use it
>       to set instance_id for DRC using its unique index to address David 
>       Gibson's concern.
>     - Rename VMS_CSTM to VMS_LINKED based on Paolo Bonzini's suggestions.
>     - Clean up qjson stuff in put_qtailq. 
>     - Add trace for put_qtailq and get_qtailq based on David Gilbert's 
>       suggestion.
> 
> It is based on David's ppc-for-2.7. Comments are welcome. Previous versions are:
> 
> v3: - Simplify overall design followng discussion with Paolo. No longer need
>       metadata to migrate QTAILQ.
>     - Extend VMStateInfo instead of adding similar fields to VMStateField.
>     - Clean up macros in qemu/queue.h.
> (link: https://lists.nongnu.org/archive/html/qemu-devel/2016-05/msg05695.html)
> 
> v2: - Introduce a general approach to migrate QTAILQ in qemu/queue.h.
>     - Migrate signalled field in the DRC state.
>     - Put the newly added migrating fields in subsections so that backward 
>       migration is not broken.  
>     - Set detach_cb field right after migration so that a migrated hot-unplug
>       event could finish its course.
> (link: https://lists.nongnu.org/archive/html/qemu-devel/2016-05/msg04188.html)
> 
> v1: - Inital version.
> (link: https://lists.nongnu.org/archive/html/qemu-devel/2016-04/msg02601.html)
> 
> To make guest device (PCI, CPU and memory) hotplug work together 
> with guest migration, spapr drc state needs be transmitted in
> migration. This patch defines the VMStateDescription struct for
> spapr drc state to enable it.
> 
> To fix the potential racing between hotplug events on guest and 
> guest migration, ccs_list and pending_events of spapr state need be 
> transmitted in migration. This patch also takes care of it.
> 
> Jianjun Duan (6):
>   migration: alternative way to set instance_id in SaveStateEntry
>   migration: spapr_drc: defined VMStateDescription struct
>   migration: extend VMStateInfo
>   migration: migrate QTAILQ
>   migration: spapr: migrate ccs_list in spapr state
>   migration: spapr: migrate pending_events of spapr state
> 
>  hw/net/vmxnet3.c            |  18 +++--
>  hw/nvram/eeprom93xx.c       |   6 +-
>  hw/nvram/fw_cfg.c           |   6 +-
>  hw/pci/msix.c               |   6 +-
>  hw/pci/pci.c                |  12 ++--
>  hw/pci/shpc.c               |   5 +-
>  hw/ppc/spapr.c              |  67 ++++++++++++++++++
>  hw/ppc/spapr_drc.c          |  69 +++++++++++++++++++
>  hw/ppc/spapr_events.c       |  22 +++---
>  hw/ppc/spapr_pci.c          |  22 ++++++
>  hw/scsi/scsi-bus.c          |   6 +-
>  hw/timer/twl92230.c         |   6 +-
>  hw/usb/redirect.c           |  18 +++--
>  hw/virtio/virtio-pci.c      |   6 +-
>  hw/virtio/virtio.c          |   6 +-
>  include/hw/ppc/spapr.h      |   3 +-
>  include/hw/ppc/spapr_drc.h  |   9 +++
>  include/hw/qdev-core.h      |   6 ++
>  include/migration/vmstate.h |  36 ++++++++--
>  include/qemu/queue.h        |  32 +++++++++
>  migration/savevm.c          |  25 +++++--
>  migration/vmstate.c         | 161 ++++++++++++++++++++++++++++++++++----------
>  target-alpha/machine.c      |   5 +-
>  target-arm/machine.c        |  12 ++--
>  target-i386/machine.c       |  21 ++++--
>  target-mips/machine.c       |  10 +--
>  target-ppc/machine.c        |  10 +--
>  target-sparc/machine.c      |   5 +-
>  trace-events                |   4 ++
>  29 files changed, 505 insertions(+), 109 deletions(-)
> 

Re: [Qemu-devel] [Qemu-ppc] [QEMU PATCH v4 0/6] migration: ensure hotplug and migration work together

[David Gibson]

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On Thu, Sep 29, 2016 at 09:55:30AM -0700, Jianjun Duan wrote:
> ping

I'm sorry, this fell off my radar.  Can you please rebase and resend
your latest version.

> 
> On 06/27/2016 09:59 AM, Jianjun Duan wrote:
> > Hi all,
> >    The previous patches seem to get buried deep somewhere. I am resending them
> >  without RFC tag. Comments are welcome.
> > 
> > v4: - Introduce a way to set customized instance_id in SaveStateEntry. Use it
> >       to set instance_id for DRC using its unique index to address David 
> >       Gibson's concern.
> >     - Rename VMS_CSTM to VMS_LINKED based on Paolo Bonzini's suggestions.
> >     - Clean up qjson stuff in put_qtailq. 
> >     - Add trace for put_qtailq and get_qtailq based on David Gilbert's 
> >       suggestion.
> > 
> > It is based on David's ppc-for-2.7. Comments are welcome. Previous versions are:
> > 
> > v3: - Simplify overall design followng discussion with Paolo. No longer need
> >       metadata to migrate QTAILQ.
> >     - Extend VMStateInfo instead of adding similar fields to VMStateField.
> >     - Clean up macros in qemu/queue.h.
> > (link: https://lists.nongnu.org/archive/html/qemu-devel/2016-05/msg05695.html)
> > 
> > v2: - Introduce a general approach to migrate QTAILQ in qemu/queue.h.
> >     - Migrate signalled field in the DRC state.
> >     - Put the newly added migrating fields in subsections so that backward 
> >       migration is not broken.  
> >     - Set detach_cb field right after migration so that a migrated hot-unplug
> >       event could finish its course.
> > (link: https://lists.nongnu.org/archive/html/qemu-devel/2016-05/msg04188.html)
> > 
> > v1: - Inital version.
> > (link: https://lists.nongnu.org/archive/html/qemu-devel/2016-04/msg02601.html)
> > 
> > To make guest device (PCI, CPU and memory) hotplug work together 
> > with guest migration, spapr drc state needs be transmitted in
> > migration. This patch defines the VMStateDescription struct for
> > spapr drc state to enable it.
> > 
> > To fix the potential racing between hotplug events on guest and 
> > guest migration, ccs_list and pending_events of spapr state need be 
> > transmitted in migration. This patch also takes care of it.
> > 
> > Jianjun Duan (6):
> >   migration: alternative way to set instance_id in SaveStateEntry
> >   migration: spapr_drc: defined VMStateDescription struct
> >   migration: extend VMStateInfo
> >   migration: migrate QTAILQ
> >   migration: spapr: migrate ccs_list in spapr state
> >   migration: spapr: migrate pending_events of spapr state
> > 
> >  hw/net/vmxnet3.c            |  18 +++--
> >  hw/nvram/eeprom93xx.c       |   6 +-
> >  hw/nvram/fw_cfg.c           |   6 +-
> >  hw/pci/msix.c               |   6 +-
> >  hw/pci/pci.c                |  12 ++--
> >  hw/pci/shpc.c               |   5 +-
> >  hw/ppc/spapr.c              |  67 ++++++++++++++++++
> >  hw/ppc/spapr_drc.c          |  69 +++++++++++++++++++
> >  hw/ppc/spapr_events.c       |  22 +++---
> >  hw/ppc/spapr_pci.c          |  22 ++++++
> >  hw/scsi/scsi-bus.c          |   6 +-
> >  hw/timer/twl92230.c         |   6 +-
> >  hw/usb/redirect.c           |  18 +++--
> >  hw/virtio/virtio-pci.c      |   6 +-
> >  hw/virtio/virtio.c          |   6 +-
> >  include/hw/ppc/spapr.h      |   3 +-
> >  include/hw/ppc/spapr_drc.h  |   9 +++
> >  include/hw/qdev-core.h      |   6 ++
> >  include/migration/vmstate.h |  36 ++++++++--
> >  include/qemu/queue.h        |  32 +++++++++
> >  migration/savevm.c          |  25 +++++--
> >  migration/vmstate.c         | 161 ++++++++++++++++++++++++++++++++++----------
> >  target-alpha/machine.c      |   5 +-
> >  target-arm/machine.c        |  12 ++--
> >  target-i386/machine.c       |  21 ++++--
> >  target-mips/machine.c       |  10 +--
> >  target-ppc/machine.c        |  10 +--
> >  target-sparc/machine.c      |   5 +-
> >  trace-events                |   4 ++
> >  29 files changed, 505 insertions(+), 109 deletions(-)
> > 
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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