Re: [PATCH V4 09/43] vfio/container: register container for cpr

[Cédric Le Goater]

On 5/29/25 21:24, Steve Sistare wrote:

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.sist...@oracle.com>

Reviewed-by: Cédric Le Goater <c...@redhat.com>

Thanks,

C.

---
  include/hw/vfio/vfio-container.h |  2 ++
  include/hw/vfio/vfio-cpr.h       | 15 +++++++++
  hw/vfio/container.c              |  6 ++--
  hw/vfio/cpr-legacy.c             | 69 ++++++++++++++++++++++++++++++++++++++++
  hw/vfio/cpr.c                    |  5 ++-
  hw/vfio/meson.build              |  1 +
  6 files changed, 92 insertions(+), 6 deletions(-)
  create mode 100644 hw/vfio/cpr-legacy.c

diff --git a/include/hw/vfio/vfio-container.h b/include/hw/vfio/vfio-container.h
index afc498d..21e5807 100644
--- a/include/hw/vfio/vfio-container.h
+++ b/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);

diff --git a/include/hw/vfio/vfio-cpr.h b/include/hw/vfio/vfio-cpr.h
index 750ea5b..d4e0bd5 100644
--- a/include/hw/vfio/vfio-cpr.h
+++ b/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);
diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index 0f948d0..7d2035c 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -643,7 +643,7 @@ 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 +679,7 @@ 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 +720,7 @@ 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);

diff --git a/hw/vfio/cpr-legacy.c b/hw/vfio/cpr-legacy.c

new file mode 100644
index 0000000..419b9fb
--- /dev/null
+++ b/hw/vfio/cpr-legacy.c
@@ -0,0 +1,69 @@
+/*
+ * 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 "hw/vfio/vfio-cpr.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);
+}
diff --git a/hw/vfio/cpr.c b/hw/vfio/cpr.c
index 0210e76..0e59612 100644
--- a/hw/vfio/cpr.c
+++ b/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()) {
diff --git a/hw/vfio/meson.build b/hw/vfio/meson.build
index bccb050..73d29f9 100644
--- a/hw/vfio/meson.build
+++ b/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',