On 6/9/2025 4:30 PM, Cédric Le Goater wrote:
On 5/29/25 21:24, Steve Sistare wrote:
Register a vfio iommufd container and device for CPR, replacing the generic
CPR register call with a more specific iommufd register call.  Add a
blocker if the kernel does not support IOMMU_IOAS_CHANGE_PROCESS.

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>
---
  include/hw/vfio/vfio-cpr.h | 12 +++++++
  include/system/iommufd.h   |  1 +
  backends/iommufd.c         | 10 ++++++
  hw/vfio/cpr-iommufd.c      | 84 ++++++++++++++++++++++++++++++++++++++++++++++
  hw/vfio/iommufd.c          |  6 ++--
  hw/vfio/meson.build        |  1 +
  6 files changed, 112 insertions(+), 2 deletions(-)
  create mode 100644 hw/vfio/cpr-iommufd.c

diff --git a/include/hw/vfio/vfio-cpr.h b/include/hw/vfio/vfio-cpr.h
index 170a116..b9b77ae 100644
--- a/include/hw/vfio/vfio-cpr.h
+++ b/include/hw/vfio/vfio-cpr.h
@@ -15,7 +15,10 @@
  struct VFIOContainer;
  struct VFIOContainerBase;
  struct VFIOGroup;
+struct VFIODevice;
  struct VFIOPCIDevice;
+struct VFIOIOMMUFDContainer;
+struct IOMMUFDBackend;
  typedef struct VFIOContainerCPR {
      Error *blocker;
@@ -43,6 +46,15 @@ bool vfio_cpr_register_container(struct VFIOContainerBase 
*bcontainer,
                                   Error **errp);
  void vfio_cpr_unregister_container(struct VFIOContainerBase *bcontainer);
+bool vfio_iommufd_cpr_register_container(struct VFIOIOMMUFDContainer 
*container,
+                                         Error **errp);
+void vfio_iommufd_cpr_unregister_container(
+    struct VFIOIOMMUFDContainer *container);
+bool vfio_iommufd_cpr_register_iommufd(struct IOMMUFDBackend *be, Error 
**errp);
+void vfio_iommufd_cpr_unregister_iommufd(struct IOMMUFDBackend *be);
+void vfio_iommufd_cpr_register_device(struct VFIODevice *vbasedev);
+void vfio_iommufd_cpr_unregister_device(struct VFIODevice *vbasedev);
+
  int vfio_cpr_group_get_device_fd(int d, const char *name);
  bool vfio_cpr_container_match(struct VFIOContainer *container,
diff --git a/include/system/iommufd.h b/include/system/iommufd.h
index db9ed53..3c58ea8 100644
--- a/include/system/iommufd.h
+++ b/include/system/iommufd.h
@@ -32,6 +32,7 @@ struct IOMMUFDBackend {
      /*< protected >*/
      int fd;            /* /dev/iommu file descriptor */
      bool owned;        /* is the /dev/iommu opened internally */
+    Error *cpr_blocker;/* set if be does not support CPR */
      uint32_t users;
      /*< public >*/
diff --git a/backends/iommufd.c b/backends/iommufd.c
index ed8bb4c..2e9d6cb 100644
--- a/backends/iommufd.c
+++ b/backends/iommufd.c
@@ -108,6 +108,13 @@ bool iommufd_backend_connect(IOMMUFDBackend *be, Error 
**errp)
          }
          be->fd = fd;
      }
+    if (!be->users && !vfio_iommufd_cpr_register_iommufd(be, errp)) {
+        if (be->owned) {
+            close(be->fd);
+            be->fd = -1;
+        }
+        return false;
+    }
      be->users++;
      trace_iommufd_backend_connect(be->fd, be->owned, be->users);
@@ -125,6 +132,9 @@ void iommufd_backend_disconnect(IOMMUFDBackend *be)
          be->fd = -1;
      }
  out:
+    if (!be->users) {
+        vfio_iommufd_cpr_unregister_iommufd(be);
+    }
      trace_iommufd_backend_disconnect(be->fd, be->users);
  }
diff --git a/hw/vfio/cpr-iommufd.c b/hw/vfio/cpr-iommufd.c
new file mode 100644
index 0000000..60bd7e8
--- /dev/null
+++ b/hw/vfio/cpr-iommufd.c
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2024-2025 Oracle and/or its affiliates.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "hw/vfio/vfio-cpr.h"
+#include "migration/blocker.h"
+#include "migration/cpr.h"
+#include "migration/migration.h"
+#include "migration/vmstate.h"
+#include "system/iommufd.h"
+#include "vfio-iommufd.h"
+
+static bool vfio_cpr_supported(IOMMUFDBackend *be, Error **errp)
+{
+    if (!iommufd_change_process_capable(be)) {
+        if (errp) {
+            error_setg(errp, "vfio iommufd backend does not support "
+                       "IOMMU_IOAS_CHANGE_PROCESS");
+        }
+        return false;
+    }
+    return true;
+}
+
+static const VMStateDescription iommufd_cpr_vmstate = {
+    .name = "iommufd",
+    .version_id = 0,
+    .minimum_version_id = 0,
+    .needed = cpr_incoming_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+bool vfio_iommufd_cpr_register_iommufd(IOMMUFDBackend *be, Error **errp)
+{
+    Error **cpr_blocker = &be->cpr_blocker;
+
+    if (!vfio_cpr_supported(be, cpr_blocker)) {
+        return migrate_add_blocker_modes(cpr_blocker, errp,
+                                         MIG_MODE_CPR_TRANSFER, -1) == 0;
+    }
+
+    vmstate_register(NULL, -1, &iommufd_cpr_vmstate, be);
+
+    return true;
+}
+
+void vfio_iommufd_cpr_unregister_iommufd(IOMMUFDBackend *be)
+{
+    vmstate_unregister(NULL, &iommufd_cpr_vmstate, be);
+    migrate_del_blocker(&be->cpr_blocker);
+}
+
+bool vfio_iommufd_cpr_register_container(VFIOIOMMUFDContainer *container,
+                                         Error **errp)
+{
+    VFIOContainerBase *bcontainer = &container->bcontainer;
+
+    migration_add_notifier_mode(&bcontainer->cpr_reboot_notifier,
+                                vfio_cpr_reboot_notifier,
+                                MIG_MODE_CPR_REBOOT);
+
+    return true;
+}
+
+void vfio_iommufd_cpr_unregister_container(VFIOIOMMUFDContainer *container)
+{
+    VFIOContainerBase *bcontainer = &container->bcontainer;
+
+    migration_remove_notifier(&bcontainer->cpr_reboot_notifier);
+}
+
+void vfio_iommufd_cpr_register_device(VFIODevice *vbasedev)
+{
+}
+
+void vfio_iommufd_cpr_unregister_device(VFIODevice *vbasedev)
+{
+}
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index ca00d08..c690c2c 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -446,7 +446,7 @@ static void 
iommufd_cdev_container_destroy(VFIOIOMMUFDContainer *container)
      if (!QLIST_EMPTY(&bcontainer->device_list)) {
          return;
      }
-    vfio_cpr_unregister_container(bcontainer);
+    vfio_iommufd_cpr_unregister_container(container);
      vfio_listener_unregister(bcontainer);
      iommufd_backend_free_id(container->be, container->ioas_id);
      object_unref(container);
@@ -592,7 +592,7 @@ static bool iommufd_cdev_attach(const char *name, 
VFIODevice *vbasedev,
          goto err_listener_register;
      }
-    if (!vfio_cpr_register_container(bcontainer, errp)) {
+    if (!vfio_iommufd_cpr_register_container(container, errp)) {
          goto err_listener_register;
      }
@@ -619,6 +619,7 @@ found_container:
      }
      vfio_device_prepare(vbasedev, bcontainer, &dev_info);
+    vfio_iommufd_cpr_register_device(vbasedev);
      trace_iommufd_cdev_device_info(vbasedev->name, devfd, vbasedev->num_irqs,
                                     vbasedev->num_regions, vbasedev->flags);
@@ -656,6 +657,7 @@ static void iommufd_cdev_detach(VFIODevice *vbasedev)
      iommufd_cdev_container_destroy(container);
      vfio_address_space_put(space);
+    vfio_iommufd_cpr_unregister_device(vbasedev);
      iommufd_cdev_unbind_and_disconnect(vbasedev);
      close(vbasedev->fd);
  }
diff --git a/hw/vfio/meson.build b/hw/vfio/meson.build
index 98134a7..12711fb 100644
--- a/hw/vfio/meson.build
+++ b/hw/vfio/meson.build
@@ -23,6 +23,7 @@ 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-iommufd.c',

This file should be compiled under CONFIG_IOMMUFD.

Sure, will fix.
Tomorrow I plan to rebase to the lastest master, add this and the few other
comments that came up for V4, and send V5.  Sound OK?

- Steve


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