migrate: add migration blockers

index 41c3c24..6764d3a 100644
@@ -398,6 +398,18 @@ static MigrationState *migrate_init(Monitor *mon, int detach, int blk, int inc)
     return s;
 }
 
+static GSList *migration_blockers;
+
+void migrate_add_blocker(Error *reason)
+{
+    migration_blockers = g_slist_prepend(migration_blockers, reason);
+}
+
+void migrate_del_blocker(Error *reason)
+{
+    migration_blockers = g_slist_remove(migration_blockers, reason);
+}
+
 int do_migrate(Monitor *mon, const QDict *qdict, QObject **ret_data)
 {
     MigrationState *s = migrate_get_current();

@@ -417,6 +429,12 @@ int do_migrate(Monitor *mon, const QDict *qdict, QObject **ret_data)
         return -1;
     }
 
+    if (migration_blockers) {
+        Error *err = migration_blockers->data;
+        qerror_report_err(err);
+        return -1;
+    }
+
     s = migrate_init(mon, detach, blk, inc);
 
     if (strstart(uri, "tcp:", &p)) {

index 1b8ee58..0682179 100644
@@ -17,6 +17,7 @@
 #include "qdict.h"
 #include "qemu-common.h"
 #include "notify.h"
+#include "error.h"
 
 typedef struct MigrationState MigrationState;
 

@@ -89,4 +90,18 @@ int ram_load(QEMUFile *f, void *opaque, int version_id);
 
 extern int incoming_expected;
 
+/**
+ * @migrate_add_blocker - prevent migration from proceeding
+ *
+ * @reason - an error to be returned whenever migration is attempted
+ */
+void migrate_add_blocker(Error *reason);
+
+/**
+ * @migrate_del_blocker - remove a blocking error from migration
+ *
+ * @reason - the error blocking migration
+ */
+void migrate_del_blocker(Error *reason);
+
 #endif

index 242fbea..a3a0e98 100644
@@ -18,6 +18,8 @@
 #include "pci.h"
 #include "msix.h"
 #include "kvm.h"
+#include "migration.h"
+#include "qerror.h"
 
 #include <sys/mman.h>
 #include <sys/types.h>

@@ -78,6 +80,8 @@ typedef struct IVShmemState {
     uint32_t features;
     EventfdEntry *eventfd_table;
 
+    Error *migration_blocker;
+
     char * shmobj;
     char * sizearg;
     char * role;

@@ -646,7 +650,8 @@ static int pci_ivshmem_init(PCIDevice *dev)
     }
 
     if (s->role_val == IVSHMEM_PEER) {
-        register_device_unmigratable(&s->dev.qdev, "ivshmem", s);
+        error_set(&s->migration_blocker, QERR_DEVICE_FEATURE_BLOCKS_MIGRATION, "ivshmem", "peer mode");
+        migrate_add_blocker(s->migration_blocker);
     }
 
     pci_conf = s->dev.config;

@@ -741,6 +746,11 @@ static int pci_ivshmem_uninit(PCIDevice *dev)
 {
     IVShmemState *s = DO_UPCAST(IVShmemState, dev, dev);
 
+    if (s->migration_blocker) {
+        migrate_del_blocker(s->migration_blocker);
+        error_free(s->migration_blocker);
+    }
+
     memory_region_destroy(&s->ivshmem_mmio);
     memory_region_del_subregion(&s->bar, &s->ivshmem);
     memory_region_destroy(&s->ivshmem);

index 4b48b39..8e30e2d 100644
@@ -73,6 +73,10 @@ static const QErrorStringTable qerror_table[] = {
         .desc      = "Device '%(device)' is in use",
     },
     {
+        .error_fmt = QERR_DEVICE_FEATURE_BLOCKS_MIGRATION,
+        .desc      = "Migration is disabled when using feature '%(feature)' in device '%(device)'",
+    },
+    {
         .error_fmt = QERR_DEVICE_LOCKED,
         .desc      = "Device '%(device)' is locked",
     },

index d4bfcfd..7e2eebf 100644
@@ -72,6 +72,9 @@ QError *qobject_to_qerror(const QObject *obj);
 #define QERR_DEVICE_IN_USE \
     "{ 'class': 'DeviceInUse', 'data': { 'device': %s } }"
 
+#define QERR_DEVICE_FEATURE_BLOCKS_MIGRATION \
+    "{ 'class': 'DeviceFeatureBlocksMigration', 'data': { 'device': %s, 'feature': %s } }"
+
 #define QERR_DEVICE_LOCKED \
     "{ 'class': 'DeviceLocked', 'data': { 'device': %s } }"
 

index bee16c0..f53cd4c 100644
@@ -1255,31 +1255,6 @@ void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque)
     }
 }
 
-/* mark a device as not to be migrated, that is the device should be
-   unplugged before migration */
-void register_device_unmigratable(DeviceState *dev, const char *idstr,
-                                                            void *opaque)
-{
-    SaveStateEntry *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), "/");
-            g_free(path);
-        }
-    }
-    pstrcat(id, sizeof(id), idstr);
-
-    QTAILQ_FOREACH(se, &savevm_handlers, entry) {
-        if (strcmp(se->idstr, id) == 0 && se->opaque == opaque) {
-            se->no_migrate = 1;
-        }
-    }
-}
-
 int vmstate_register_with_alias_id(DeviceState *dev, int instance_id,
                                    const VMStateDescription *vmsd,
                                    void *opaque, int alias_id,

610 lines not on this page · raw message

index 86910b0..d015887 100644
@@ -2839,6 +2839,22 @@ int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
     }
 }
 
+void bdrv_invalidate_cache(BlockDriverState *bs)
+{
+    if (bs->drv && bs->drv->bdrv_invalidate_cache) {
+        bs->drv->bdrv_invalidate_cache(bs);
+    }
+}
+
+void bdrv_invalidate_cache_all(void)
+{
+    BlockDriverState *bs;
+
+    QTAILQ_FOREACH(bs, &bdrv_states, list) {
+        bdrv_invalidate_cache(bs);
+    }
+}
+
 int bdrv_flush(BlockDriverState *bs)
 {
     Coroutine *co;

index 051a25d..a826059 100644
@@ -197,6 +197,10 @@ BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs,
         unsigned long int req, void *buf,
         BlockDriverCompletionFunc *cb, void *opaque);
 
+/* Invalidate any cached metadata used by image formats */
+void bdrv_invalidate_cache(BlockDriverState *bs);
+void bdrv_invalidate_cache_all(void);
+
 /* Ensure contents are flushed to disk.  */
 int bdrv_flush(BlockDriverState *bs);
 int coroutine_fn bdrv_co_flush(BlockDriverState *bs);

index 1ec4921..77c0187 100644
@@ -88,6 +88,11 @@ struct BlockDriver {
         int64_t sector_num, int nb_sectors);
 
     /*
+     * Invalidate any cached meta-data.
+     */
+    void (*bdrv_invalidate_cache)(BlockDriverState *bs);
+
+    /*
      * Flushes all data that was already written to the OS all the way down to
      * the disk (for example raw-posix calls fsync()).
      */

index 6764d3a..8280d71 100644
@@ -89,6 +89,9 @@ void process_incoming_migration(QEMUFile *f)
     qemu_announce_self();
     DPRINTF("successfully loaded vm state\n");
 
+    /* Make sure all file formats flush their mutable metadata */
+    bdrv_invalidate_cache_all();
+
     if (autostart) {
         vm_start();
     } else {

index 5c784ee..d7805ce 100644
@@ -240,6 +240,7 @@ static int qcow2_open(BlockDriverState *bs, int flags)
     s->cluster_data = qemu_blockalign(bs, QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size
                                   + 512);
     s->cluster_cache_offset = -1;
+    s->flags = flags;
 
     ret = qcow2_refcount_init(bs);
     if (ret != 0) {

@@ -632,6 +633,37 @@ static void qcow2_close(BlockDriverState *bs)
     qcow2_refcount_close(bs);
 }
 
+static void qcow2_invalidate_cache(BlockDriverState *bs)
+{
+    BDRVQcowState *s = bs->opaque;
+    int flags = s->flags;
+    AES_KEY aes_encrypt_key;
+    AES_KEY aes_decrypt_key;
+    uint32_t crypt_method = 0;
+
+    /*
+     * Backing files are read-only which makes all of their metadata immutable,
+     * that means we don't have to worry about reopening them here.
+     */
+
+    if (s->crypt_method) {
+        crypt_method = s->crypt_method;
+        memcpy(&aes_encrypt_key, &s->aes_encrypt_key, sizeof(aes_encrypt_key));
+        memcpy(&aes_decrypt_key, &s->aes_decrypt_key, sizeof(aes_decrypt_key));
+    }
+
+    qcow2_close(bs);
+
+    memset(s, 0, sizeof(BDRVQcowState));
+    qcow2_open(bs, flags);
+
+    if (crypt_method) {
+        s->crypt_method = crypt_method;
+        memcpy(&s->aes_encrypt_key, &aes_encrypt_key, sizeof(aes_encrypt_key));
+        memcpy(&s->aes_decrypt_key, &aes_decrypt_key, sizeof(aes_decrypt_key));
+    }
+}
+
 /*
  * Updates the variable length parts of the qcow2 header, i.e. the backing file
  * name and all extensions. qcow2 was not designed to allow such changes, so if

@@ -1269,6 +1301,8 @@ static BlockDriver bdrv_qcow2 = {
 
     .bdrv_change_backing_file   = qcow2_change_backing_file,
 
+    .bdrv_invalidate_cache      = qcow2_invalidate_cache,
+
     .create_options = qcow2_create_options,
     .bdrv_check = qcow2_check,
 };

index 531af39..4e44eea 100644
@@ -125,6 +125,8 @@ typedef struct BDRVQcowState {
     int snapshots_size;
     int nb_snapshots;
     QCowSnapshot *snapshots;
+
+    int flags;
 } BDRVQcowState;
 
 /* XXX: use std qcow open function ? */

index d032a45..7e22e77 100644
@@ -16,6 +16,7 @@
 #include "trace.h"
 #include "qed.h"
 #include "qerror.h"
+#include "migration.h"
 
 static void qed_aio_cancel(BlockDriverAIOCB *blockacb)
 {

@@ -504,6 +505,12 @@ static int bdrv_qed_open(BlockDriverState *bs, int flags)
     s->need_check_timer = qemu_new_timer_ns(vm_clock,
                                             qed_need_check_timer_cb, s);
 
+    error_set(&s->migration_blocker,
+              QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
+              "qed", bs->device_name, "live migration");
+    migrate_add_blocker(s->migration_blocker);
+
+
 out:
     if (ret) {
         qed_free_l2_cache(&s->l2_cache);

@@ -516,6 +523,9 @@ static void bdrv_qed_close(BlockDriverState *bs)
 {
     BDRVQEDState *s = bs->opaque;
 
+    migrate_del_blocker(s->migration_blocker);
+    error_free(s->migration_blocker);
+
     qed_cancel_need_check_timer(s);
     qemu_free_timer(s->need_check_timer);
 

index 388fdb3..62cbd3b 100644
@@ -164,6 +164,8 @@ typedef struct {
 
     /* Periodic flush and clear need check flag */
     QEMUTimer *need_check_timer;
+
+    Error *migration_blocker;
 } BDRVQEDState;
 
 enum {

index e9f7fe1..5df7279 100644
@@ -15,6 +15,7 @@
 #include "monitor.h"
 #include "qemu-timer.h"
 #include "qemu-log.h"
+#include "migration.h"
 
 #include <sys/time.h>
 

@@ -92,3 +93,11 @@ int64_t qemu_get_clock_ns(QEMUClock *clock)
 {
     return 0;
 }
+
+void migrate_add_blocker(Error *reason)
+{
+}
+
+void migrate_del_blocker(Error *reason)
+{
+}

index 8e30e2d..fdf62b9 100644
@@ -49,6 +49,10 @@ static const QErrorStringTable qerror_table[] = {
         .desc      = "Device '%(device)' can't go on a %(bad_bus_type) bus",
     },
     {
+        .error_fmt = QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
+        .desc      = "Block format '%(format)' used by device '%(name)' does not support feature '%(feature)'",
+    },
+    {
         .error_fmt = QERR_BUS_NOT_FOUND,
         .desc      = "Bus '%(bus)' not found",
     },

index 7e2eebf..2d3d43b 100644
@@ -54,6 +54,9 @@ QError *qobject_to_qerror(const QObject *obj);
 #define QERR_BAD_BUS_FOR_DEVICE \
     "{ 'class': 'BadBusForDevice', 'data': { 'device': %s, 'bad_bus_type': %s } }"
 
+#define QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED \
+    "{ 'class': 'BlockFormatFeatureNotSupported', 'data': { 'format': %s, 'name': %s, 'feature': %s } }"
+
 #define QERR_BUS_NOT_FOUND \
     "{ 'class': 'BusNotFound', 'data': { 'bus': %s } }"