vfio: Introduce a new header file for internal migration services

Gather all VFIO migration related declarations into
"vfio-migration-internal.h" to reduce exposure of VFIO internals in
"hw/vfio/vfio-common.h".

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/20250326075122.1299361-7-clg@redhat.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>

hw/vfio/common.c

@@ -43,6 +43,7 @@
 #include "migration/qemu-file.h"
 #include "system/tcg.h"
 #include "system/tpm.h"
+#include "vfio-migration-internal.h"
 
 VFIODeviceList vfio_device_list =
     QLIST_HEAD_INITIALIZER(vfio_device_list);

hw/vfio/migration-multifd.c

@@ -11,7 +11,6 @@
 
 #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"
@@ -22,6 +21,7 @@
 #include "io/channel-buffer.h"
 #include "migration/qemu-file.h"
 #include "migration-multifd.h"
+#include "vfio-migration-internal.h"
 #include "trace.h"
 
 #define VFIO_DEVICE_STATE_CONFIG_STATE (1)

hw/vfio/migration.c

@@ -31,6 +31,7 @@
 #include "pci.h"
 #include "trace.h"
 #include "hw/hw.h"
+#include "vfio-migration-internal.h"
 
 /*
  * This is an arbitrary size based on migration of mlx5 devices, where typically

hw/vfio/pci.c

@@ -44,6 +44,7 @@
 #include "migration/blocker.h"
 #include "migration/qemu-file.h"
 #include "system/iommufd.h"
+#include "vfio-migration-internal.h"
 
 #define TYPE_VFIO_PCI_NOHOTPLUG "vfio-pci-nohotplug"
 

hw/vfio/vfio-migration-internal.h

@@ -0,0 +1,72 @@
+/*
+ * VFIO migration
+ *
+ * Copyright Red Hat, Inc. 2025
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef HW_VFIO_VFIO_MIGRATION_INTERNAL_H
+#define HW_VFIO_VFIO_MIGRATION_INTERNAL_H
+
+#ifdef CONFIG_LINUX
+#include <linux/vfio.h>
+#endif
+
+#include "qemu/typedefs.h"
+#include "qemu/notify.h"
+
+/*
+ * Flags to be used as unique delimiters for VFIO devices in the migration
+ * stream. These flags are composed as:
+ * 0xffffffff => MSB 32-bit all 1s
+ * 0xef10     => Magic ID, represents emulated (virtual) function IO
+ * 0x0000     => 16-bits reserved for flags
+ *
+ * The beginning of state information is marked by _DEV_CONFIG_STATE,
+ * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a
+ * certain state information is marked by _END_OF_STATE.
+ */
+#define VFIO_MIG_FLAG_END_OF_STATE      (0xffffffffef100001ULL)
+#define VFIO_MIG_FLAG_DEV_CONFIG_STATE  (0xffffffffef100002ULL)
+#define VFIO_MIG_FLAG_DEV_SETUP_STATE   (0xffffffffef100003ULL)
+#define VFIO_MIG_FLAG_DEV_DATA_STATE    (0xffffffffef100004ULL)
+#define VFIO_MIG_FLAG_DEV_INIT_DATA_SENT (0xffffffffef100005ULL)
+
+typedef struct VFIODevice VFIODevice;
+typedef struct VFIOMultifd VFIOMultifd;
+
+typedef struct VFIOMigration {
+    struct VFIODevice *vbasedev;
+    VMChangeStateEntry *vm_state;
+    NotifierWithReturn migration_state;
+    uint32_t device_state;
+    int data_fd;
+    void *data_buffer;
+    size_t data_buffer_size;
+    uint64_t mig_flags;
+    uint64_t precopy_init_size;
+    uint64_t precopy_dirty_size;
+    bool multifd_transfer;
+    VFIOMultifd *multifd;
+    bool initial_data_sent;
+
+    bool event_save_iterate_started;
+    bool event_precopy_empty_hit;
+} VFIOMigration;
+
+bool vfio_migration_realize(VFIODevice *vbasedev, Error **errp);
+void vfio_migration_exit(VFIODevice *vbasedev);
+int vfio_save_device_config_state(QEMUFile *f, void *opaque, Error **errp);
+int vfio_load_device_config_state(QEMUFile *f, void *opaque);
+
+#ifdef CONFIG_LINUX
+int vfio_migration_set_state(VFIODevice *vbasedev,
+                             enum vfio_device_mig_state new_state,
+                             enum vfio_device_mig_state recover_state,
+                             Error **errp);
+#endif
+
+void vfio_migration_add_bytes_transferred(unsigned long val);
+
+#endif /* HW_VFIO_VFIO_MIGRATION_INTERNAL_H */

include/hw/vfio/vfio-common.h

@@ -23,7 +23,6 @@
 
 #include "system/memory.h"
 #include "qemu/queue.h"
-#include "qemu/notify.h"
 #include "ui/console.h"
 #include "hw/display/ramfb.h"
 #ifdef CONFIG_LINUX
@@ -36,23 +35,6 @@
 
 #define VFIO_MSG_PREFIX "vfio %s: "
 
-/*
- * Flags to be used as unique delimiters for VFIO devices in the migration
- * stream. These flags are composed as:
- * 0xffffffff => MSB 32-bit all 1s
- * 0xef10     => Magic ID, represents emulated (virtual) function IO
- * 0x0000     => 16-bits reserved for flags
- *
- * The beginning of state information is marked by _DEV_CONFIG_STATE,
- * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a
- * certain state information is marked by _END_OF_STATE.
- */
-#define VFIO_MIG_FLAG_END_OF_STATE      (0xffffffffef100001ULL)
-#define VFIO_MIG_FLAG_DEV_CONFIG_STATE  (0xffffffffef100002ULL)
-#define VFIO_MIG_FLAG_DEV_SETUP_STATE   (0xffffffffef100003ULL)
-#define VFIO_MIG_FLAG_DEV_DATA_STATE    (0xffffffffef100004ULL)
-#define VFIO_MIG_FLAG_DEV_INIT_DATA_SENT (0xffffffffef100005ULL)
-
 enum {
     VFIO_DEVICE_TYPE_PCI = 0,
     VFIO_DEVICE_TYPE_PLATFORM = 1,
@@ -78,27 +60,6 @@ typedef struct VFIORegion {
     uint8_t nr; /* cache the region number for debug */
 } VFIORegion;
 
-typedef struct VFIOMultifd VFIOMultifd;
-
-typedef struct VFIOMigration {
-    struct VFIODevice *vbasedev;
-    VMChangeStateEntry *vm_state;
-    NotifierWithReturn migration_state;
-    uint32_t device_state;
-    int data_fd;
-    void *data_buffer;
-    size_t data_buffer_size;
-    uint64_t mig_flags;
-    uint64_t precopy_init_size;
-    uint64_t precopy_dirty_size;
-    bool multifd_transfer;
-    VFIOMultifd *multifd;
-    bool initial_data_sent;
-
-    bool event_save_iterate_started;
-    bool event_precopy_empty_hit;
-} VFIOMigration;
-
 struct VFIOGroup;
 
 typedef struct VFIOContainer {
@@ -136,6 +97,7 @@ typedef struct VFIOIOMMUFDContainer {
 OBJECT_DECLARE_SIMPLE_TYPE(VFIOIOMMUFDContainer, VFIO_IOMMU_IOMMUFD);
 
 typedef struct VFIODeviceOps VFIODeviceOps;
+typedef struct VFIOMigration VFIOMigration;
 
 typedef struct VFIODevice {
     QLIST_ENTRY(VFIODevice) next;
@@ -290,13 +252,9 @@ extern VFIODeviceList vfio_device_list;
 extern const MemoryListener vfio_memory_listener;
 extern int vfio_kvm_device_fd;
 
-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);
 
-int vfio_save_device_config_state(QEMUFile *f, void *opaque, Error **errp);
-int vfio_load_device_config_state(QEMUFile *f, void *opaque);
-
 #ifdef CONFIG_LINUX
 int vfio_get_region_info(VFIODevice *vbasedev, int index,
                          struct vfio_region_info **info);
@@ -311,16 +269,8 @@ struct vfio_info_cap_header *
 vfio_get_device_info_cap(struct vfio_device_info *info, uint16_t id);
 struct vfio_info_cap_header *
 vfio_get_cap(void *ptr, uint32_t cap_offset, uint16_t id);
-
-int vfio_migration_set_state(VFIODevice *vbasedev,
-                             enum vfio_device_mig_state new_state,
-                             enum vfio_device_mig_state recover_state,
-                             Error **errp);
 #endif
 
-bool vfio_migration_realize(VFIODevice *vbasedev, Error **errp);
-void vfio_migration_exit(VFIODevice *vbasedev);
-
 int vfio_bitmap_alloc(VFIOBitmap *vbmap, hwaddr size);
 bool vfio_devices_all_dirty_tracking_started(
     const VFIOContainerBase *bcontainer);