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WHvStartPartitionMigration

Begins migrating a partition on the source host.

Syntax

HRESULT
WINAPI
WHvStartPartitionMigration(
    _In_ WHV_PARTITION_HANDLE Partition,
    _Out_ HANDLE* MigrationHandle
    );

Parameters

Partition

Handle to the partition object to migrate.

MigrationHandle

Receives a handle that represents the in-progress migration. The source process transfers this handle to the destination process, which passes it to WHvAcceptPartitionMigration to receive the partition.

Return Value

If the function succeeds, the return value is S_OK.

If the partition is already involved in a migration, the function returns HRESULT_FROM_WIN32(ERROR_INVALID_STATE).

Remarks

The WHvStartPartitionMigration function starts the source side of a partition migration. It serializes the partition's state, properties, virtual processors, doorbells, and virtual PCI devices and sends them, together with the necessary handles, to the destination process. The send operation remains pending until the destination host accepts the partition with WHvAcceptPartitionMigration.

After this call succeeds, the partition enters a migrating state in which operations that would invalidate the already-serialized state are blocked. From this point the source must either finish the migration with WHvCompletePartitionMigration or abort it with WHvCancelPartitionMigration. Deleting the partition with WHvDeletePartition also cancels the migration.

The handle returned in MigrationHandle is a standard Win32 handle. The source process is responsible for transferring it to the destination process by any suitable means (for example, handle duplication). WHvAcceptPartitionMigration closes the handle on the destination side when it succeeds.

The typical migration sequence is:

  1. The source calls WHvStartPartitionMigration to begin migration and obtain MigrationHandle.
  2. The destination calls WHvAcceptPartitionMigration with the transferred handle to create the target partition.
  3. The source calls WHvCompletePartitionMigration to finalize and release the source partition.
  4. The destination calls WHvSetupPartition to complete the migration on the target and resume normal operation.

Requirements

Requirement Value
Minimum supported Windows Windows 10, version 20H2 (x64); Windows 11, version 24H2, build 26100.3915 (Arm64)
Header WinHvPlatform.h
Library WinHvPlatform.lib
DLL WinHvPlatform.dll
Architecture x64, Arm64

See also

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