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authorSteve Sistare <steven.sistare@oracle.com>2025-06-10 08:39:15 -0700
committerCédric Le Goater <clg@redhat.com>2025-06-11 14:01:58 +0200
commit081c09dc52bab0facfdd1d34fd466479af6ac531 (patch)
tree5d7ece58e8798c3bce55db52a91070a3c25acc5d
parentf95fd60ac164a75c586ce29ebcc94bb6df85b52a (diff)
downloadfocaccia-qemu-081c09dc52bab0facfdd1d34fd466479af6ac531.tar.gz
focaccia-qemu-081c09dc52bab0facfdd1d34fd466479af6ac531.zip
migration: lower handler priority
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 <steven.sistare@oracle.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/qemu-devel/1749569991-25171-3-git-send-email-steven.sistare@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
-rw-r--r--include/migration/vmstate.h6
-rw-r--r--migration/savevm.c4
2 files changed, 7 insertions, 3 deletions
diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index a1dfab4460..1ff7bd9ac4 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -155,7 +155,11 @@ enum VMStateFlags {
 };
 
 typedef enum {
-    MIG_PRI_DEFAULT = 0,
+    MIG_PRI_UNINITIALIZED = 0,  /* An uninitialized priority field maps to */
+                                /* MIG_PRI_DEFAULT in save_state_priority */
+
+    MIG_PRI_LOW,                /* 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 52105dd2f1..bb04a4520d 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -266,7 +266,7 @@ 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,
 };
 
@@ -737,7 +737,7 @@ 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;