Merge tag 'migration-20250711-pull-request' of https://gitlab.com/farosas/qemu into staging

Migration pull request

- General cleanups around: postcopy, bg-snapshot, migration hooks,
  migration completion and formatting of 'info migrate'.

- Overhaul of postcopy blocktime tracking.

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# gpg:                 aka "Fabiano Almeida Rosas <fabiano.rosas@suse.com>" [unknown]
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* tag 'migration-20250711-pull-request' of https://gitlab.com/farosas/qemu: (26 commits)
  migration: Rename save_live_complete_precopy_thread to save_complete_precopy_thread
  migration/postcopy: Add latency distribution report for blocktime
  migration/postcopy: blocktime allows track / report non-vCPU faults
  migration/postcopy: Optimize blocktime fault tracking with hashtable
  migration/postcopy: Cleanup the total blocktime accounting
  migration/postcopy: Cache the tid->vcpu mapping for blocktime
  migration/postcopy: Initialize blocktime context only until listen
  migration/postcopy: Report fault latencies in blocktime
  migration/postcopy: Add blocktime fault counts per-vcpu
  migration/postcopy: Bring blocktime layer to ns level
  migration/postcopy: Drop PostcopyBlocktimeContext.start_time
  migration/postcopy: Make all blocktime vars 64bits
  migration/postcopy: Drop all atomic ops in blocktime feature
  migration/postcopy: Push blocktime start/end into page req mutex
  migration: Add option to set postcopy-blocktime
  migration/postcopy: Avoid clearing dirty bitmap for postcopy too
  migration: Rewrite the migration complete detect logic
  migration/ram: Add tracepoints for ram_save_complete()
  migration/ram: One less indent for ram_find_and_save_block()
  migration: qemu_savevm_complete*() helpers
  ...

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

3 files changed, 20 insertions, 28 deletions

diff --git a/include/migration/misc.h b/include/migration/misc.h
index 8fd36eb..a261f99 100644
--- a/include/migration/misc.h
+++ b/include/migration/misc.h
@@ -119,19 +119,19 @@ bool migrate_uri_parse(const char *uri, MigrationChannel **channel,
                        Error **errp);
 
 /* migration/multifd-device-state.c */
-typedef struct SaveLiveCompletePrecopyThreadData {
-    SaveLiveCompletePrecopyThreadHandler hdlr;
+typedef struct SaveCompletePrecopyThreadData {
+    SaveCompletePrecopyThreadHandler hdlr;
     char *idstr;
     uint32_t instance_id;
     void *handler_opaque;
-} SaveLiveCompletePrecopyThreadData;
+} SaveCompletePrecopyThreadData;
 
 bool multifd_queue_device_state(char *idstr, uint32_t instance_id,
                                 char *data, size_t len);
 bool multifd_device_state_supported(void);
 
 void
-multifd_spawn_device_state_save_thread(SaveLiveCompletePrecopyThreadHandler hdlr,
+multifd_spawn_device_state_save_thread(SaveCompletePrecopyThreadHandler hdlr,
                                        char *idstr, uint32_t instance_id,
                                        void *opaque);
 
diff --git a/include/migration/register.h b/include/migration/register.h
index b79dc81..ae79794 100644
--- a/include/migration/register.h
+++ b/include/migration/register.h
@@ -78,51 +78,43 @@ typedef struct SaveVMHandlers {
     void (*save_cleanup)(void *opaque);
 
     /**
-     * @save_live_complete_postcopy
+     * @save_complete
      *
-     * Called at the end of postcopy for all postcopyable devices.
+     * Transmits the last section for the device containing any
+     * remaining data at the end phase of migration.
      *
-     * @f: QEMUFile where to send the data
-     * @opaque: data pointer passed to register_savevm_live()
+     * For precopy, this will be invoked _during_ the switchover phase
+     * after source VM is stopped.
      *
-     * Returns zero to indicate success and negative for error
-     */
-    int (*save_live_complete_postcopy)(QEMUFile *f, void *opaque);
-
-    /**
-     * @save_live_complete_precopy
-     *
-     * Transmits the last section for the device containing any
-     * remaining data at the end of a precopy phase. When postcopy is
-     * enabled, devices that support postcopy will skip this step,
-     * where the final data will be flushed at the end of postcopy via
-     * @save_live_complete_postcopy instead.
+     * For postcopy, this will be invoked _after_ the switchover phase
+     * (except some very unusual cases, like PMEM ramblocks), while
+     * destination VM can be running.
      *
      * @f: QEMUFile where to send the data
      * @opaque: data pointer passed to register_savevm_live()
      *
      * Returns zero to indicate success and negative for error
      */
-    int (*save_live_complete_precopy)(QEMUFile *f, void *opaque);
+    int (*save_complete)(QEMUFile *f, void *opaque);
 
     /**
-     * @save_live_complete_precopy_thread (invoked in a separate thread)
+     * @save_complete_precopy_thread (invoked in a separate thread)
      *
      * Called at the end of a precopy phase from a separate worker thread
      * in configurations where multifd device state transfer is supported
      * in order to perform asynchronous transmission of the remaining data in
-     * parallel with @save_live_complete_precopy handlers.
+     * parallel with @save_complete handlers.
      * When postcopy is enabled, devices that support postcopy will skip this
      * step.
      *
-     * @d: a #SaveLiveCompletePrecopyThreadData containing parameters that the
+     * @d: a #SaveCompletePrecopyThreadData containing parameters that the
      * handler may need, including this device section idstr and instance_id,
      * and opaque data pointer passed to register_savevm_live().
      * @errp: pointer to Error*, to store an error if it happens.
      *
      * Returns true to indicate success and false for errors.
      */
-    SaveLiveCompletePrecopyThreadHandler save_live_complete_precopy_thread;
+    SaveCompletePrecopyThreadHandler save_complete_precopy_thread;
 
     /* This runs both outside and inside the BQL.  */
 
diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
index 507f081..4a94af9 100644
--- a/include/qemu/typedefs.h
+++ b/include/qemu/typedefs.h
@@ -109,7 +109,7 @@ typedef struct QString QString;
 typedef struct RAMBlock RAMBlock;
 typedef struct Range Range;
 typedef struct ReservedRegion ReservedRegion;
-typedef struct SaveLiveCompletePrecopyThreadData SaveLiveCompletePrecopyThreadData;
+typedef struct SaveCompletePrecopyThreadData SaveCompletePrecopyThreadData;
 typedef struct SHPCDevice SHPCDevice;
 typedef struct SSIBus SSIBus;
 typedef struct TCGCPUOps TCGCPUOps;
@@ -135,7 +135,7 @@ typedef struct IRQState *qemu_irq;
 typedef void (*qemu_irq_handler)(void *opaque, int n, int level);
 typedef bool (*MigrationLoadThread)(void *opaque, bool *should_quit,
                                     Error **errp);
-typedef bool (*SaveLiveCompletePrecopyThreadHandler)(SaveLiveCompletePrecopyThreadData *d,
-                                                     Error **errp);
+typedef bool (*SaveCompletePrecopyThreadHandler)(SaveCompletePrecopyThreadData *d,
+                                                 Error **errp);
 
 #endif /* QEMU_TYPEDEFS_H */