@@ -2070,8 +2070,9 @@ static int memory_try_enable_merging(void *addr, size_t len)
return qemu_madvise(addr, len, QEMU_MADV_MERGEABLE);
}
-/* Only legal before guest might have detected the memory size: e.g. on
- * incoming migration, or right after reset.
+/*
+ * Resizing RAM while migrating can result in the migration being canceled.
+ * Care has to be taken if the guest might have already detected the memory.
*
* As memory core doesn't know how is memory accessed, it is up to
* resize callback to update device state and/or add assertions to detect
@@ -113,7 +113,7 @@ typedef struct IOMMUNotifier IOMMUNotifier;
#define RAM_SHARED (1 << 1)
/* Only a portion of RAM (used_length) is actually used, and migrated.
- * This used_length size can change across reboots.
+ * Resizing RAM while migrating can result in the migration being canceled.
*/
#define RAM_RESIZEABLE (1 << 2)
@@ -843,7 +843,9 @@ void memory_region_init_ram_shared_nomigrate(MemoryRegion *mr,
* RAM. Accesses into the region will
* modify memory directly. Only an initial
* portion of this RAM is actually used.
- * The used size can change across reboots.
+ * Changing the size while migrating
+ * can result in the migration being
+ * canceled.
*
* @mr: the #MemoryRegion to be initialized.
* @owner: the object that tracks the region's reference count
@@ -1464,8 +1466,8 @@ void *memory_region_get_ram_ptr(MemoryRegion *mr);
/* memory_region_ram_resize: Resize a RAM region.
*
- * Only legal before guest might have detected the memory size: e.g. on
- * incoming migration, or right after reset.
+ * Resizing RAM while migrating can result in the migration being canceled.
+ * Care has to be taken if the guest might have already detected the memory.
*
* @mr: a memory region created with @memory_region_init_resizeable_ram.
* @newsize: the new size the region
@@ -181,13 +181,18 @@ void migration_object_init(void)
}
}
+void migration_cancel(void)
+{
+ migrate_fd_cancel(current_migration);
+}
+
void migration_shutdown(void)
{
/*
* Cancel the current migration - that will (eventually)
* stop the migration using this structure
*/
- migrate_fd_cancel(current_migration);
+ migration_cancel();
object_unref(OBJECT(current_migration));
}
@@ -2066,7 +2071,7 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
void qmp_migrate_cancel(Error **errp)
{
- migrate_fd_cancel(migrate_get_current());
+ migration_cancel();
}
void qmp_migrate_continue(MigrationStatus state, Error **errp)
@@ -346,5 +346,6 @@ int foreach_not_ignored_block(RAMBlockIterFunc func, void *opaque);
void migration_make_urgent_request(void);
void migration_consume_urgent_request(void);
bool migration_rate_limit(void);
+void migration_cancel(void);
#endif
@@ -52,6 +52,7 @@
#include "migration/colo.h"
#include "block.h"
#include "sysemu/sysemu.h"
+#include "sysemu/runstate.h"
#include "savevm.h"
#include "qemu/iov.h"
#include "multifd.h"
@@ -3752,8 +3753,38 @@ static SaveVMHandlers savevm_ram_handlers = {
.resume_prepare = ram_resume_prepare,
};
+static void ram_mig_ram_block_resized(RAMBlockNotifier *n, void *host,
+ size_t old_size, size_t new_size)
+{
+ ram_addr_t offset;
+ Error *err = NULL;
+ RAMBlock *rb = qemu_ram_block_from_host(host, false, &offset);
+
+ if (ramblock_is_ignored(rb)) {
+ return;
+ }
+
+ if (!migration_is_idle()) {
+ /*
+ * Precopy code on the source cannot deal with the size of RAM blocks
+ * changing at random points in time - especially after sending the
+ * RAM block sizes to the migration stream, they must no longer change.
+ * Abort and indicate a proper reason.
+ */
+ error_setg(&err, "RAM block '%s' resized during precopy.", rb->idstr);
+ migrate_set_error(migrate_get_current(), err);
+ error_free(err);
+ migration_cancel();
+ }
+}
+
+static RAMBlockNotifier ram_mig_ram_notifier = {
+ .ram_block_resized = ram_mig_ram_block_resized,
+};
+
void ram_mig_init(void)
{
qemu_mutex_init(&XBZRLE.lock);
register_savevm_live("ram", 0, 4, &savevm_ram_handlers, &ram_state);
+ ram_block_notifier_add(&ram_mig_ram_notifier);
}