Merge tag 'pull-vfio-20250306' of https://github.com/legoater/qemu into staging

vfio queue:

* Added property documentation
* Added Minor fixes
* Implemented basic PCI PM capability backing
* Promoted new IGD maintainer
* Deprecated vfio-plaform
* Extended VFIO migration with multifd support

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* tag 'pull-vfio-20250306' of https://github.com/legoater/qemu: (42 commits)
  hw/core/machine: Add compat for x-migration-multifd-transfer VFIO property
  vfio/migration: Make x-migration-multifd-transfer VFIO property mutable
  vfio/migration: Add x-migration-multifd-transfer VFIO property
  vfio/migration: Multifd device state transfer support - send side
  vfio/migration: Multifd device state transfer support - config loading support
  migration/qemu-file: Define g_autoptr() cleanup function for QEMUFile
  vfio/migration: Multifd device state transfer support - load thread
  vfio/migration: Multifd device state transfer support - received buffers queuing
  vfio/migration: Setup and cleanup multifd transfer in these general methods
  vfio/migration: Multifd setup/cleanup functions and associated VFIOMultifd
  vfio/migration: Multifd device state transfer - add support checking function
  vfio/migration: Multifd device state transfer support - basic types
  vfio/migration: Move migration channel flags to vfio-common.h header file
  vfio/migration: Add vfio_add_bytes_transferred()
  vfio/migration: Convert bytes_transferred counter to atomic
  vfio/migration: Add load_device_config_state_start trace event
  migration: Add save_live_complete_precopy_thread handler
  migration/multifd: Add multifd_device_state_supported()
  migration/multifd: Make MultiFDSendData a struct
  migration/multifd: Device state transfer support - send side
  ...

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

1 files changed, 16 insertions, 1 deletions

diff --git a/migration/migration.c b/migration/migration.c
index c597aa707e..1833cfe358 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -402,11 +402,24 @@ void migration_incoming_state_destroy(void)
     struct MigrationIncomingState *mis = migration_incoming_get_current();
 
     multifd_recv_cleanup();
+
     /*
      * RAM state cleanup needs to happen after multifd cleanup, because
      * multifd threads can use some of its states (receivedmap).
+     * The VFIO load_cleanup() implementation is BQL-sensitive. It requires
+     * BQL must NOT be taken when recycling load threads, so that it won't
+     * block the load threads from making progress on address space
+     * modification operations.
+     *
+     * To make it work, we could try to not take BQL for all load_cleanup(),
+     * or conditionally unlock BQL only if bql_locked() in VFIO.
+     *
+     * Since most existing call sites take BQL for load_cleanup(), make
+     * it simple by taking BQL always as the rule, so that VFIO can unlock
+     * BQL and retake unconditionally.
      */
-    qemu_loadvm_state_cleanup();
+    assert(bql_locked());
+    qemu_loadvm_state_cleanup(mis);
 
     if (mis->to_src_file) {
         /* Tell source that we are done */
@@ -2891,6 +2904,8 @@ static bool migration_switchover_start(MigrationState *s, Error **errp)
 
     precopy_notify_complete();
 
+    qemu_savevm_maybe_send_switchover_start(s->to_dst_file);
+
     return true;
 }