vfio/container: register container for cpr

Register a legacy container for cpr-transfer, replacing the generic CPR
register call with a more specific legacy container register call.  Add a
blocker if the kernel does not support VFIO_UPDATE_VADDR or VFIO_UNMAP_ALL.

This is mostly boiler plate.  The fields to to saved and restored are added
in subsequent patches.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/1749569991-25171-4-git-send-email-steven.sistare@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>

hw/vfio/container.c

@@ -33,7 +33,6 @@
 #include "qapi/error.h"
 #include "pci.h"
 #include "hw/vfio/vfio-container.h"
-#include "hw/vfio/vfio-cpr.h"
 #include "vfio-helpers.h"
 #include "vfio-listener.h"
 
@@ -643,7 +642,7 @@ static bool vfio_container_connect(VFIOGroup *group, AddressSpace *as,
     new_container = true;
     bcontainer = &container->bcontainer;
 
-    if (!vfio_cpr_register_container(bcontainer, errp)) {
+    if (!vfio_legacy_cpr_register_container(container, errp)) {
         goto fail;
     }
 
@@ -679,7 +678,7 @@ fail:
         vioc->release(bcontainer);
     }
     if (new_container) {
-        vfio_cpr_unregister_container(bcontainer);
+        vfio_legacy_cpr_unregister_container(container);
         object_unref(container);
     }
     if (fd >= 0) {
@@ -720,7 +719,7 @@ static void vfio_container_disconnect(VFIOGroup *group)
         VFIOAddressSpace *space = bcontainer->space;
 
         trace_vfio_container_disconnect(container->fd);
-        vfio_cpr_unregister_container(bcontainer);
+        vfio_legacy_cpr_unregister_container(container);
         close(container->fd);
         object_unref(container);
 

hw/vfio/cpr-legacy.c

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2021-2025 Oracle and/or its affiliates.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include <sys/ioctl.h>
+#include <linux/vfio.h>
+#include "qemu/osdep.h"
+#include "hw/vfio/vfio-container.h"
+#include "migration/blocker.h"
+#include "migration/cpr.h"
+#include "migration/migration.h"
+#include "migration/vmstate.h"
+#include "qapi/error.h"
+
+static bool vfio_cpr_supported(VFIOContainer *container, Error **errp)
+{
+    if (!ioctl(container->fd, VFIO_CHECK_EXTENSION, VFIO_UPDATE_VADDR)) {
+        error_setg(errp, "VFIO container does not support VFIO_UPDATE_VADDR");
+        return false;
+
+    } else if (!ioctl(container->fd, VFIO_CHECK_EXTENSION, VFIO_UNMAP_ALL)) {
+        error_setg(errp, "VFIO container does not support VFIO_UNMAP_ALL");
+        return false;
+
+    } else {
+        return true;
+    }
+}
+
+static const VMStateDescription vfio_container_vmstate = {
+    .name = "vfio-container",
+    .version_id = 0,
+    .minimum_version_id = 0,
+    .needed = cpr_incoming_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+bool vfio_legacy_cpr_register_container(VFIOContainer *container, Error **errp)
+{
+    VFIOContainerBase *bcontainer = &container->bcontainer;
+    Error **cpr_blocker = &container->cpr.blocker;
+
+    migration_add_notifier_mode(&bcontainer->cpr_reboot_notifier,
+                                vfio_cpr_reboot_notifier,
+                                MIG_MODE_CPR_REBOOT);
+
+    if (!vfio_cpr_supported(container, cpr_blocker)) {
+        return migrate_add_blocker_modes(cpr_blocker, errp,
+                                         MIG_MODE_CPR_TRANSFER, -1) == 0;
+    }
+
+    vmstate_register(NULL, -1, &vfio_container_vmstate, container);
+
+    return true;
+}
+
+void vfio_legacy_cpr_unregister_container(VFIOContainer *container)
+{
+    VFIOContainerBase *bcontainer = &container->bcontainer;
+
+    migration_remove_notifier(&bcontainer->cpr_reboot_notifier);
+    migrate_del_blocker(&container->cpr.blocker);
+    vmstate_unregister(NULL, &vfio_container_vmstate, container);
+}

hw/vfio/cpr.c

@@ -7,13 +7,12 @@
 
 #include "qemu/osdep.h"
 #include "hw/vfio/vfio-device.h"
-#include "migration/misc.h"
 #include "hw/vfio/vfio-cpr.h"
 #include "qapi/error.h"
 #include "system/runstate.h"
 
-static int vfio_cpr_reboot_notifier(NotifierWithReturn *notifier,
-                                    MigrationEvent *e, Error **errp)
+int vfio_cpr_reboot_notifier(NotifierWithReturn *notifier,
+                             MigrationEvent *e, Error **errp)
 {
     if (e->type == MIG_EVENT_PRECOPY_SETUP &&
         !runstate_check(RUN_STATE_SUSPENDED) && !vm_get_suspended()) {

hw/vfio/meson.build

@@ -21,6 +21,7 @@ system_ss.add(when: 'CONFIG_VFIO_XGMAC', if_true: files('calxeda-xgmac.c'))
 system_ss.add(when: 'CONFIG_VFIO_AMD_XGBE', if_true: files('amd-xgbe.c'))
 system_ss.add(when: 'CONFIG_VFIO', if_true: files(
   'cpr.c',
+  'cpr-legacy.c',
   'device.c',
   'migration.c',
   'migration-multifd.c',

include/hw/vfio/vfio-container.h

@@ -10,6 +10,7 @@
 #define HW_VFIO_CONTAINER_H
 
 #include "hw/vfio/vfio-container-base.h"
+#include "hw/vfio/vfio-cpr.h"
 
 typedef struct VFIOContainer VFIOContainer;
 typedef struct VFIODevice VFIODevice;
@@ -29,6 +30,7 @@ typedef struct VFIOContainer {
     int fd; /* /dev/vfio/vfio, empowered by the attached groups */
     unsigned iommu_type;
     QLIST_HEAD(, VFIOGroup) group_list;
+    VFIOContainerCPR cpr;
 } VFIOContainer;
 
 OBJECT_DECLARE_SIMPLE_TYPE(VFIOContainer, VFIO_IOMMU_LEGACY);

include/hw/vfio/vfio-cpr.h

@@ -9,8 +9,23 @@
 #ifndef HW_VFIO_VFIO_CPR_H
 #define HW_VFIO_VFIO_CPR_H
 
+#include "migration/misc.h"
+
+struct VFIOContainer;
 struct VFIOContainerBase;
 
+typedef struct VFIOContainerCPR {
+    Error *blocker;
+} VFIOContainerCPR;
+
+
+bool vfio_legacy_cpr_register_container(struct VFIOContainer *container,
+                                        Error **errp);
+void vfio_legacy_cpr_unregister_container(struct VFIOContainer *container);
+
+int vfio_cpr_reboot_notifier(NotifierWithReturn *notifier, MigrationEvent *e,
+                             Error **errp);
+
 bool vfio_cpr_register_container(struct VFIOContainerBase *bcontainer,
                                  Error **errp);
 void vfio_cpr_unregister_container(struct VFIOContainerBase *bcontainer);