savevm: Make use of DeviceState
For callers that pass a device we can traverse up the qdev tree and
make use of the BusInfo.get_dev_path information for creating unique
savevm id strings. This avoids needing to rely on the instance number,
which can cause problems with device initialization order and hotplug.
For compatibility, we also store away the old id string and instance
so we can accept migrations from VMs as we add new get_dev_path
implementations.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/savevm.c b/savevm.c
index d874d08..ee27989 100644
--- a/savevm.c
+++ b/savevm.c
@@ -72,6 +72,7 @@
#include "qemu-common.h"
#include "hw/hw.h"
+#include "hw/qdev.h"
#include "net.h"
#include "monitor.h"
#include "sysemu.h"
@@ -985,6 +986,11 @@
.put = put_unused_buffer,
};
+typedef struct CompatEntry {
+ char idstr[256];
+ int instance_id;
+} CompatEntry;
+
typedef struct SaveStateEntry {
QTAILQ_ENTRY(SaveStateEntry) entry;
char idstr[256];
@@ -998,6 +1004,7 @@
LoadStateHandler *load_state;
const VMStateDescription *vmsd;
void *opaque;
+ CompatEntry *compat;
} SaveStateEntry;
@@ -1019,6 +1026,23 @@
return instance_id;
}
+static int calculate_compat_instance_id(const char *idstr)
+{
+ SaveStateEntry *se;
+ int instance_id = 0;
+
+ QTAILQ_FOREACH(se, &savevm_handlers, entry) {
+ if (!se->compat)
+ continue;
+
+ if (strcmp(idstr, se->compat->idstr) == 0
+ && instance_id <= se->compat->instance_id) {
+ instance_id = se->compat->instance_id + 1;
+ }
+ }
+ return instance_id;
+}
+
/* TODO: Individual devices generally have very little idea about the rest
of the system, so instance_id should be removed/replaced.
Meanwhile pass -1 as instance_id if you do not already have a clearly
@@ -1036,7 +1060,6 @@
SaveStateEntry *se;
se = qemu_mallocz(sizeof(SaveStateEntry));
- pstrcpy(se->idstr, sizeof(se->idstr), idstr);
se->version_id = version_id;
se->section_id = global_section_id++;
se->set_params = set_params;
@@ -1046,11 +1069,28 @@
se->opaque = opaque;
se->vmsd = NULL;
+ if (dev && dev->parent_bus && dev->parent_bus->info->get_dev_path) {
+ char *id = dev->parent_bus->info->get_dev_path(dev);
+ if (id) {
+ pstrcpy(se->idstr, sizeof(se->idstr), id);
+ pstrcat(se->idstr, sizeof(se->idstr), "/");
+ qemu_free(id);
+
+ se->compat = qemu_mallocz(sizeof(CompatEntry));
+ pstrcpy(se->compat->idstr, sizeof(se->compat->idstr), idstr);
+ se->compat->instance_id = instance_id == -1 ?
+ calculate_compat_instance_id(idstr) : instance_id;
+ instance_id = -1;
+ }
+ }
+ pstrcat(se->idstr, sizeof(se->idstr), idstr);
+
if (instance_id == -1) {
- se->instance_id = calculate_new_instance_id(idstr);
+ se->instance_id = calculate_new_instance_id(se->idstr);
} else {
se->instance_id = instance_id;
}
+ assert(!se->compat || se->instance_id == 0);
/* add at the end of list */
QTAILQ_INSERT_TAIL(&savevm_handlers, se, entry);
return 0;
@@ -1071,9 +1111,20 @@
void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque)
{
SaveStateEntry *se, *new_se;
+ char id[256] = "";
+
+ if (dev && dev->parent_bus && dev->parent_bus->info->get_dev_path) {
+ char *path = dev->parent_bus->info->get_dev_path(dev);
+ if (path) {
+ pstrcpy(id, sizeof(id), path);
+ pstrcat(id, sizeof(id), "/");
+ qemu_free(path);
+ }
+ }
+ pstrcat(id, sizeof(id), idstr);
QTAILQ_FOREACH_SAFE(se, &savevm_handlers, entry, new_se) {
- if (strcmp(se->idstr, idstr) == 0 && se->opaque == opaque) {
+ if (strcmp(se->idstr, id) == 0 && se->opaque == opaque) {
QTAILQ_REMOVE(&savevm_handlers, se, entry);
qemu_free(se);
}
@@ -1091,7 +1142,6 @@
assert(alias_id == -1 || required_for_version >= vmsd->minimum_version_id);
se = qemu_mallocz(sizeof(SaveStateEntry));
- pstrcpy(se->idstr, sizeof(se->idstr), vmsd->name);
se->version_id = vmsd->version_id;
se->section_id = global_section_id++;
se->save_live_state = NULL;
@@ -1101,11 +1151,28 @@
se->vmsd = vmsd;
se->alias_id = alias_id;
+ if (dev && dev->parent_bus && dev->parent_bus->info->get_dev_path) {
+ char *id = dev->parent_bus->info->get_dev_path(dev);
+ if (id) {
+ pstrcpy(se->idstr, sizeof(se->idstr), id);
+ pstrcat(se->idstr, sizeof(se->idstr), "/");
+ qemu_free(id);
+
+ se->compat = qemu_mallocz(sizeof(CompatEntry));
+ pstrcpy(se->compat->idstr, sizeof(se->compat->idstr), vmsd->name);
+ se->compat->instance_id = instance_id == -1 ?
+ calculate_compat_instance_id(vmsd->name) : instance_id;
+ instance_id = -1;
+ }
+ }
+ pstrcat(se->idstr, sizeof(se->idstr), vmsd->name);
+
if (instance_id == -1) {
- se->instance_id = calculate_new_instance_id(vmsd->name);
+ se->instance_id = calculate_new_instance_id(se->idstr);
} else {
se->instance_id = instance_id;
}
+ assert(!se->compat || se->instance_id == 0);
/* add at the end of list */
QTAILQ_INSERT_TAIL(&savevm_handlers, se, entry);
return 0;
@@ -1451,6 +1518,13 @@
(instance_id == se->instance_id ||
instance_id == se->alias_id))
return se;
+ /* Migrating from an older version? */
+ if (strstr(se->idstr, idstr) && se->compat) {
+ if (!strcmp(se->compat->idstr, idstr) &&
+ (instance_id == se->compat->instance_id ||
+ instance_id == se->alias_id))
+ return se;
+ }
}
return NULL;
}
