Re: [PATCH v6 24/36] vfio/migration: Multifd setup/cleanup functions and associated VFIOMultifd

[Cédric Le Goater]

On 3/4/25 23:03, Maciej S. Szmigiero wrote:

From: "Maciej S. Szmigiero" <maciej.szmigi...@oracle.com>

Add multifd setup/cleanup functions and an associated VFIOMultifd data
structure that will contain most of the receive-side data together
with its init/cleanup methods.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigi...@oracle.com>

Reviewed-by: Cédric Le Goater <c...@redhat.com>

Thanks,

C.

---
  hw/vfio/migration-multifd.c   | 44 +++++++++++++++++++++++++++++++++++
  hw/vfio/migration-multifd.h   |  4 ++++
  include/hw/vfio/vfio-common.h |  3 +++
  3 files changed, 51 insertions(+)

diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c
index 79fae0b6296f..091dc43210ad 100644
--- a/hw/vfio/migration-multifd.c
+++ b/hw/vfio/migration-multifd.c
@@ -32,8 +32,52 @@ typedef struct VFIODeviceStatePacket {
      uint8_t data[0];
  } QEMU_PACKED VFIODeviceStatePacket;

+typedef struct VFIOMultifd {

+} VFIOMultifd;
+
+static VFIOMultifd *vfio_multifd_new(void)
+{
+    VFIOMultifd *multifd = g_new(VFIOMultifd, 1);
+
+    return multifd;
+}
+
+static void vfio_multifd_free(VFIOMultifd *multifd)
+{
+    g_free(multifd);
+}
+
+void vfio_multifd_cleanup(VFIODevice *vbasedev)
+{
+    VFIOMigration *migration = vbasedev->migration;
+
+    g_clear_pointer(&migration->multifd, vfio_multifd_free);
+}
+
  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_setup(VFIODevice *vbasedev, bool alloc_multifd, Error **errp)
+{
+    VFIOMigration *migration = vbasedev->migration;
+
+    if (!vfio_multifd_transfer_enabled(vbasedev)) {
+        /* Nothing further to check or do */
+        return true;
+    }
+
+    if (alloc_multifd) {
+        assert(!migration->multifd);
+        migration->multifd = vfio_multifd_new();
+    }
+
+    return true;
+}
diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h
index 1b60d5f67a1c..2a7a76164f29 100644
--- a/hw/vfio/migration-multifd.h
+++ b/hw/vfio/migration-multifd.h
@@ -14,6 +14,10 @@

#include "hw/vfio/vfio-common.h" +bool vfio_multifd_setup(VFIODevice *vbasedev, bool alloc_multifd, Error **errp);

+void vfio_multifd_cleanup(VFIODevice *vbasedev);
+
  bool vfio_multifd_transfer_supported(void);
+bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev);

#endif

diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index bf5d52087129..40382390692d 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;