vfio: Add migration region initialization and finalize function

Whether the VFIO device supports migration or not is decided based of
migration region query. If migration region query is successful and migration
region initialization is successful then migration is supported else
migration is blocked.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

3 files changed, 126 insertions, 0 deletions

diff --git a/hw/vfio/meson.build b/hw/vfio/meson.build
index 37efa74..da9af29 100644
--- a/hw/vfio/meson.build
+++ b/hw/vfio/meson.build
@@ -2,6 +2,7 @@ vfio_ss = ss.source_set()
 vfio_ss.add(files(
   'common.c',
   'spapr.c',
+  'migration.c',
 ))
 vfio_ss.add(when: 'CONFIG_VFIO_PCI', if_true: files(
   'display.c',
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
new file mode 100644
index 0000000..fd7faf4
--- /dev/null
+++ b/hw/vfio/migration.c
@@ -0,0 +1,122 @@
+/*
+ * Migration support for VFIO devices
+ *
+ * Copyright NVIDIA, Inc. 2020
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include <linux/vfio.h>
+
+#include "hw/vfio/vfio-common.h"
+#include "cpu.h"
+#include "migration/migration.h"
+#include "migration/qemu-file.h"
+#include "migration/register.h"
+#include "migration/blocker.h"
+#include "migration/misc.h"
+#include "qapi/error.h"
+#include "exec/ramlist.h"
+#include "exec/ram_addr.h"
+#include "pci.h"
+#include "trace.h"
+
+static void vfio_migration_exit(VFIODevice *vbasedev)
+{
+    VFIOMigration *migration = vbasedev->migration;
+
+    vfio_region_exit(&migration->region);
+    vfio_region_finalize(&migration->region);
+    g_free(vbasedev->migration);
+    vbasedev->migration = NULL;
+}
+
+static int vfio_migration_init(VFIODevice *vbasedev,
+                               struct vfio_region_info *info)
+{
+    int ret;
+    Object *obj;
+
+    if (!vbasedev->ops->vfio_get_object) {
+        return -EINVAL;
+    }
+
+    obj = vbasedev->ops->vfio_get_object(vbasedev);
+    if (!obj) {
+        return -EINVAL;
+    }
+
+    vbasedev->migration = g_new0(VFIOMigration, 1);
+
+    ret = vfio_region_setup(obj, vbasedev, &vbasedev->migration->region,
+                            info->index, "migration");
+    if (ret) {
+        error_report("%s: Failed to setup VFIO migration region %d: %s",
+                     vbasedev->name, info->index, strerror(-ret));
+        goto err;
+    }
+
+    if (!vbasedev->migration->region.size) {
+        error_report("%s: Invalid zero-sized VFIO migration region %d",
+                     vbasedev->name, info->index);
+        ret = -EINVAL;
+        goto err;
+    }
+    return 0;
+
+err:
+    vfio_migration_exit(vbasedev);
+    return ret;
+}
+
+/* ---------------------------------------------------------------------- */
+
+int vfio_migration_probe(VFIODevice *vbasedev, Error **errp)
+{
+    struct vfio_region_info *info = NULL;
+    Error *local_err = NULL;
+    int ret;
+
+    ret = vfio_get_dev_region_info(vbasedev, VFIO_REGION_TYPE_MIGRATION,
+                                   VFIO_REGION_SUBTYPE_MIGRATION, &info);
+    if (ret) {
+        goto add_blocker;
+    }
+
+    ret = vfio_migration_init(vbasedev, info);
+    if (ret) {
+        goto add_blocker;
+    }
+
+    g_free(info);
+    trace_vfio_migration_probe(vbasedev->name, info->index);
+    return 0;
+
+add_blocker:
+    error_setg(&vbasedev->migration_blocker,
+               "VFIO device doesn't support migration");
+    g_free(info);
+
+    ret = migrate_add_blocker(vbasedev->migration_blocker, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        error_free(vbasedev->migration_blocker);
+        vbasedev->migration_blocker = NULL;
+    }
+    return ret;
+}
+
+void vfio_migration_finalize(VFIODevice *vbasedev)
+{
+    if (vbasedev->migration) {
+        vfio_migration_exit(vbasedev);
+    }
+
+    if (vbasedev->migration_blocker) {
+        migrate_del_blocker(vbasedev->migration_blocker);
+        error_free(vbasedev->migration_blocker);
+        vbasedev->migration_blocker = NULL;
+    }
+}
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index a0c7b49..9ced5ec 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -145,3 +145,6 @@ vfio_display_edid_link_up(void) ""
 vfio_display_edid_link_down(void) ""
 vfio_display_edid_update(uint32_t prefx, uint32_t prefy) "%ux%u"
 vfio_display_edid_write_error(void) ""
+
+# migration.c
+vfio_migration_probe(const char *name, uint32_t index) " (%s) Region %d"