[v5,25/36] vfio/migration: Multifd device state transfer support - receive init/cleanup

Commit Message

Maciej S. Szmigiero Feb. 19, 2025, 8:34 p.m. UTC

From: "Maciej S. Szmigiero" <[e-mail]>

Add support for VFIOMultifd data structure that will contain most of the
receive-side data together with its init/cleanup methods.

Signed-off-by: Maciej S. Szmigiero <[e-mail]>
---
 hw/vfio/migration-multifd.c   | 33 +++++++++++++++++++++++++++++++++
 hw/vfio/migration-multifd.h   |  8 ++++++++
 hw/vfio/migration.c           | 29 +++++++++++++++++++++++++++--
 include/hw/vfio/vfio-common.h |  3 +++
 4 files changed, 71 insertions(+), 2 deletions(-)

Patch

diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c
index 7328ad8e925c..c2defc0efef0 100644
--- a/hw/vfio/migration-multifd.c
+++ b/hw/vfio/migration-multifd.c
@@ -41,6 +41,9 @@  typedef struct VFIOStateBuffer {
     size_t len;
 } VFIOStateBuffer;
 
+typedef struct VFIOMultifd {
+} VFIOMultifd;
+
 static void vfio_state_buffer_clear(gpointer data)
 {
     VFIOStateBuffer *lb = data;
@@ -84,8 +87,38 @@  static VFIOStateBuffer *vfio_state_buffers_at(VFIOStateBuffers *bufs, guint idx)
     return &g_array_index(bufs->array, VFIOStateBuffer, idx);
 }
 
+VFIOMultifd *vfio_multifd_new(void)
+{
+    VFIOMultifd *multifd = g_new(VFIOMultifd, 1);
+
+    return multifd;
+}
+
+void vfio_multifd_free(VFIOMultifd *multifd)
+{
+    g_free(multifd);
+}
+
 bool vfio_multifd_transfer_supported(void)
 {
     return multifd_device_state_supported() &&
         migrate_send_switchover_start();
 }
+
+bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev)
+{
+    return false;
+}
+
+bool vfio_multifd_transfer_setup(VFIODevice *vbasedev, Error **errp)
+{
+    if (vfio_multifd_transfer_enabled(vbasedev) &&
+        !vfio_multifd_transfer_supported()) {
+        error_setg(errp,
+                   "%s: Multifd device transfer requested but unsupported in the current config",
+                   vbasedev->name);
+        return false;
+    }
+
+    return true;
+}
diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h
index 8fe004c1da81..1eefba3b2eed 100644
--- a/hw/vfio/migration-multifd.h
+++ b/hw/vfio/migration-multifd.h
@@ -12,6 +12,14 @@ 
 
 #include "hw/vfio/vfio-common.h"
 
+typedef struct VFIOMultifd VFIOMultifd;
+
+VFIOMultifd *vfio_multifd_new(void);
+void vfio_multifd_free(VFIOMultifd *multifd);
+
 bool vfio_multifd_transfer_supported(void);
+bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev);
+
+bool vfio_multifd_transfer_setup(VFIODevice *vbasedev, Error **errp);
 
 #endif
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 7b79be6ad293..4311de763885 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -674,15 +674,40 @@  static void vfio_save_state(QEMUFile *f, void *opaque)
 static int vfio_load_setup(QEMUFile *f, void *opaque, Error **errp)
 {
     VFIODevice *vbasedev = opaque;
+    VFIOMigration *migration = vbasedev->migration;
+    int ret;
+
+    if (!vfio_multifd_transfer_setup(vbasedev, errp)) {
+        return -EINVAL;
+    }
+
+    ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING,
+                                   migration->device_state, errp);
+    if (ret) {
+        return ret;
+    }
 
-    return vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING,
-                                    vbasedev->migration->device_state, errp);
+    if (vfio_multifd_transfer_enabled(vbasedev)) {
+        assert(!migration->multifd);
+        migration->multifd = vfio_multifd_new();
+    }
+
+    return 0;
+}
+
+static void vfio_multifd_cleanup(VFIODevice *vbasedev)
+{
+    VFIOMigration *migration = vbasedev->migration;
+
+    g_clear_pointer(&migration->multifd, vfio_multifd_free);
 }
 
 static int vfio_load_cleanup(void *opaque)
 {
     VFIODevice *vbasedev = opaque;
 
+    vfio_multifd_cleanup(vbasedev);
+
     vfio_migration_cleanup(vbasedev);
     trace_vfio_load_cleanup(vbasedev->name);
 
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 64ee3b1a2547..ab110198bd6b 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -78,6 +78,8 @@  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;
@@ -89,6 +91,7 @@  typedef struct VFIOMigration {
     uint64_t mig_flags;
     uint64_t precopy_init_size;
     uint64_t precopy_dirty_size;
+    VFIOMultifd *multifd;
     bool initial_data_sent;
 
     bool event_save_iterate_started;