On Wed, Jan 29, 2025 at 06:42:58AM -0800, Steve Sistare wrote:
> Define a vmstate priority that is lower than the default, so its handlers
> run after all default priority handlers. Since 0 is no longer the default
> priority, translate an uninitialized priority of 0 to MIG_PRI_DEFAULT.
>
> CPR for vfio will use this to install handlers for containers that run
> after handlers for the devices that they contain.
>
> Signed-off-by: Steve Sistare <[email protected]>
> ---
> include/migration/vmstate.h | 3 ++-
> migration/savevm.c | 4 ++--
> 2 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
> index a1dfab4..3055a46 100644
> --- a/include/migration/vmstate.h
> +++ b/include/migration/vmstate.h
> @@ -155,7 +155,8 @@ enum VMStateFlags {
> };
>
> typedef enum {
> - MIG_PRI_DEFAULT = 0,
Shall we still keep a defintion for 0? Or at least add a comment link to
save_state_priority() - it might be helpful for whoever jumps to this enum
defintion when reading.. and get confused how a default value is non-zero.
Or define it as something like:
MIG_PRI_UNINITIALIZED = 0, /* Most devices don't set a priority, it will
* be routed to MIG_PRI_DEFAULT */
> + MIG_PRI_LOW = 1, /* Must happen after default */
> + MIG_PRI_DEFAULT,
> MIG_PRI_IOMMU, /* Must happen before PCI devices */
> MIG_PRI_PCI_BUS, /* Must happen before IOMMU */
> MIG_PRI_VIRTIO_MEM, /* Must happen before IOMMU */
> diff --git a/migration/savevm.c b/migration/savevm.c
> index 264bc06..5dd2dc4 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -232,7 +232,7 @@ typedef struct SaveState {
>
> static SaveState savevm_state = {
> .handlers = QTAILQ_HEAD_INITIALIZER(savevm_state.handlers),
> - .handler_pri_head = { [MIG_PRI_DEFAULT ... MIG_PRI_MAX] = NULL },
> + .handler_pri_head = { [0 ... MIG_PRI_MAX] = NULL },
> .global_section_id = 0,
> };
>
> @@ -704,7 +704,7 @@ static int calculate_compat_instance_id(const char *idstr)
>
> static inline MigrationPriority save_state_priority(SaveStateEntry *se)
> {
> - if (se->vmsd) {
> + if (se->vmsd && se->vmsd->priority) {
> return se->vmsd->priority;
> }
> return MIG_PRI_DEFAULT;
> --
> 1.8.3.1
>
--
Peter Xu
