On 5.09.2024 15:45, Avihai Horon wrote:
On 27/08/2024 20:54, Maciej S. Szmigiero wrote:External email: Use caution opening links or attachments From: "Maciej S. Szmigiero" <maciej.szmigi...@oracle.com> These SaveVMHandlers help device provide its own asynchronous transmission of the remaining data at the end of a precopy phase. In this use case the save_live_complete_precopy_begin handler might be used to mark the stream boundary before proceeding with asynchronous transmission of the remaining data while the save_live_complete_precopy_end handler might be used to mark the stream boundary after performing the asynchronous transmission. Signed-off-by: Maciej S. Szmigiero <maciej.szmigi...@oracle.com> --- include/migration/register.h | 36 ++++++++++++++++++++++++++++++++++++ migration/savevm.c | 35 +++++++++++++++++++++++++++++++++++ 2 files changed, 71 insertions(+) diff --git a/include/migration/register.h b/include/migration/register.h index f60e797894e5..9de123252edf 100644 --- a/include/migration/register.h +++ b/include/migration/register.h @@ -103,6 +103,42 @@ typedef struct SaveVMHandlers { */ int (*save_live_complete_precopy)(QEMUFile *f, void *opaque); + /** + * @save_live_complete_precopy_begin + * + * Called at the end of a precopy phase, before all + * @save_live_complete_precopy handlers and before launching + * all @save_live_complete_precopy_thread threads. + * The handler might, for example, mark the stream boundary before + * proceeding with asynchronous transmission of the remaining data via + * @save_live_complete_precopy_thread. + * When postcopy is enabled, devices that support postcopy will skip this step. + * + * @f: QEMUFile where the handler can synchronously send data before returning + * @idstr: this device section idstr + * @instance_id: this device section instance_id + * @opaque: data pointer passed to register_savevm_live() + * + * Returns zero to indicate success and negative for error + */ + int (*save_live_complete_precopy_begin)(QEMUFile *f, + char *idstr, uint32_t instance_id, + void *opaque); + /** + * @save_live_complete_precopy_end + * + * Called at the end of a precopy phase, after @save_live_complete_precopy + * handlers and after all @save_live_complete_precopy_thread threads have + * finished. When postcopy is enabled, devices that support postcopy will + * skip this step. + * + * @f: QEMUFile where the handler can synchronously send data before returning + * @opaque: data pointer passed to register_savevm_live() + * + * Returns zero to indicate success and negative for error + */ + int (*save_live_complete_precopy_end)(QEMUFile *f, void *opaque);Is this handler necessary now that migration core is responsible for the threads and joins them? I don't see VFIO implementing it later on.
It's not 100% necessary for the current implementation but preserved for future usage and code consistency with the "_begin" handler (which IS necessary).
Thanks.
Thanks, Maciej
