[PATCH v3 03/37] vfio: Introduce a new header file for external migration services

["Cédric Le Goater" <clg@redhat.com>]

The migration core subsystem makes use of the VFIO migration API to
collect statistics on the number of bytes transferred. These services
are declared in "hw/vfio/vfio-common.h" which also contains VFIO
internal declarations. Move the migration declarations into a new
header file "hw/vfio/vfio-migration.h" to reduce the exposure of VFIO
internals.

While at it, use a 'vfio_migration_' prefix for these services.

To be noted, vfio_migration_add_bytes_transferred() is a VFIO
migration internal service which we will be moved in the subsequent
patches.

Cc: Kirti Wankhede <kwankhede@nvidia.com>
Cc: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Prasad Pandit <pjp@fedoraproject.org>
Reviewed-by: John Levon <john.levon@nutanix.com>
Reviewed-by: Avihai Horon <avihaih@nvidia.com>
Link: https://lore.kernel.org/qemu-devel/20250326075122.1299361-4-clg@redhat.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 include/hw/vfio/vfio-common.h    |  5 +----
 include/hw/vfio/vfio-migration.h | 16 ++++++++++++++++
 hw/vfio/migration-multifd.c      |  5 +++--
 hw/vfio/migration.c              | 11 ++++++-----
 migration/target.c               |  8 ++++----
 5 files changed, 30 insertions(+), 15 deletions(-)
 create mode 100644 include/hw/vfio/vfio-migration.h

diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 9cfb3fb6931e71395ef1d67b0a743d8bc1433fdc..fd424a4a3d40132e940f457f9250458e50ea0b71 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -290,13 +290,10 @@ extern VFIODeviceList vfio_device_list;
 extern const MemoryListener vfio_memory_listener;
 extern int vfio_kvm_device_fd;
 
-bool vfio_mig_active(void);
 int vfio_block_multiple_devices_migration(VFIODevice *vbasedev, Error **errp);
 void vfio_unblock_multiple_devices_migration(void);
 bool vfio_viommu_preset(VFIODevice *vbasedev);
-int64_t vfio_mig_bytes_transferred(void);
-void vfio_mig_reset_bytes_transferred(void);
-void vfio_mig_add_bytes_transferred(unsigned long val);
+void vfio_migration_add_bytes_transferred(unsigned long val);
 bool vfio_device_state_is_running(VFIODevice *vbasedev);
 bool vfio_device_state_is_precopy(VFIODevice *vbasedev);
 
diff --git a/include/hw/vfio/vfio-migration.h b/include/hw/vfio/vfio-migration.h
new file mode 100644
index 0000000000000000000000000000000000000000..0d4ecd33d5d8c214bb77e0652b4405b6e43bcafa
--- /dev/null
+++ b/include/hw/vfio/vfio-migration.h
@@ -0,0 +1,16 @@
+/*
+ * VFIO migration interface
+ *
+ * Copyright Red Hat, Inc. 2025
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef HW_VFIO_VFIO_MIGRATION_H
+#define HW_VFIO_VFIO_MIGRATION_H
+
+bool vfio_migration_active(void);
+int64_t vfio_migration_bytes_transferred(void);
+void vfio_migration_reset_bytes_transferred(void);
+
+#endif /* HW_VFIO_VFIO_MIGRATION_H */
diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c
index 378f6f3bf01f6a4155fb424f8028cb5380f27f02..09aa57f5f890f37f7e36c857fd813f55b1da2fce 100644
--- a/hw/vfio/migration-multifd.c
+++ b/hw/vfio/migration-multifd.c
@@ -11,6 +11,7 @@
 
 #include "qemu/osdep.h"
 #include "hw/vfio/vfio-common.h"
+#include "hw/vfio/vfio-migration.h"
 #include "migration/misc.h"
 #include "qapi/error.h"
 #include "qemu/bswap.h"
@@ -575,7 +576,7 @@ vfio_save_complete_precopy_thread_config_state(VFIODevice *vbasedev,
         return false;
     }
 
-    vfio_mig_add_bytes_transferred(packet_len);
+    vfio_migration_add_bytes_transferred(packet_len);
 
     return true;
 }
@@ -645,7 +646,7 @@ vfio_multifd_save_complete_precopy_thread(SaveLiveCompletePrecopyThreadData *d,
             goto thread_exit;
         }
 
-        vfio_mig_add_bytes_transferred(packet_size);
+        vfio_migration_add_bytes_transferred(packet_size);
     }
 
     if (!vfio_save_complete_precopy_thread_config_state(vbasedev,
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 8bf65b8e11094b8363692dba3084b762362c7dd6..582d65932a6c590eaecd8bf0b765f27d93896c72 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -17,6 +17,7 @@
 
 #include "system/runstate.h"
 #include "hw/vfio/vfio-common.h"
+#include "hw/vfio/vfio-migration.h"
 #include "migration/misc.h"
 #include "migration/savevm.h"
 #include "migration/vmstate.h"
@@ -373,7 +374,7 @@ static ssize_t vfio_save_block(QEMUFile *f, VFIOMigration *migration)
     qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE);
     qemu_put_be64(f, data_size);
     qemu_put_buffer(f, migration->data_buffer, data_size);
-    vfio_mig_add_bytes_transferred(data_size);
+    vfio_migration_add_bytes_transferred(data_size);
 
     trace_vfio_save_block(migration->vbasedev->name, data_size);
 
@@ -1047,22 +1048,22 @@ static int vfio_block_migration(VFIODevice *vbasedev, Error *err, Error **errp)
 
 /* ---------------------------------------------------------------------- */
 
-int64_t vfio_mig_bytes_transferred(void)
+int64_t vfio_migration_bytes_transferred(void)
 {
     return MIN(qatomic_read(&bytes_transferred), INT64_MAX);
 }
 
-void vfio_mig_reset_bytes_transferred(void)
+void vfio_migration_reset_bytes_transferred(void)
 {
     qatomic_set(&bytes_transferred, 0);
 }
 
-void vfio_mig_add_bytes_transferred(unsigned long val)
+void vfio_migration_add_bytes_transferred(unsigned long val)
 {
     qatomic_add(&bytes_transferred, val);
 }
 
-bool vfio_mig_active(void)
+bool vfio_migration_active(void)
 {
     VFIODevice *vbasedev;
 
diff --git a/migration/target.c b/migration/target.c
index f5d8cfe7c2a3473f4bd3f5068145598c60973c58..12fd399f0c521c5c28535b58f24feab6845947fd 100644
--- a/migration/target.c
+++ b/migration/target.c
@@ -11,21 +11,21 @@
 #include CONFIG_DEVICES
 
 #ifdef CONFIG_VFIO
-#include "hw/vfio/vfio-common.h"
+#include "hw/vfio/vfio-migration.h"
 #endif
 
 #ifdef CONFIG_VFIO
 void migration_populate_vfio_info(MigrationInfo *info)
 {
-    if (vfio_mig_active()) {
+    if (vfio_migration_active()) {
         info->vfio = g_malloc0(sizeof(*info->vfio));
-        info->vfio->transferred = vfio_mig_bytes_transferred();
+        info->vfio->transferred = vfio_migration_bytes_transferred();
     }
 }
 
 void migration_reset_vfio_bytes_transferred(void)
 {
-    vfio_mig_reset_bytes_transferred();
+    vfio_migration_reset_bytes_transferred();
 }
 #else
 void migration_populate_vfio_info(MigrationInfo *info)
-- 
2.49.0