[Qemu-devel] [PATCH v4 04/13] vfio: Add migration region initialization and finalize function

[Kirti Wankhede <kwankhede@nvidia.com>]

- Migration functions are implemented for VFIO_DEVICE_TYPE_PCI device in this
  patch series.
- VFIO device supports migration or not is decided based of migration region
  query. If migration region query 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>
---
 hw/vfio/Makefile.objs         |   2 +-
 hw/vfio/migration.c           | 137 ++++++++++++++++++++++++++++++++++++++++++
 include/hw/vfio/vfio-common.h |  14 +++++
 3 files changed, 152 insertions(+), 1 deletion(-)
 create mode 100644 hw/vfio/migration.c

diff --git a/hw/vfio/Makefile.objs b/hw/vfio/Makefile.objs
index abad8b818c9b..36033d1437c5 100644
--- a/hw/vfio/Makefile.objs
+++ b/hw/vfio/Makefile.objs
@@ -1,4 +1,4 @@
-obj-y += common.o spapr.o
+obj-y += common.o spapr.o migration.o
 obj-$(CONFIG_VFIO_PCI) += pci.o pci-quirks.o display.o
 obj-$(CONFIG_VFIO_CCW) += ccw.o
 obj-$(CONFIG_VFIO_PLATFORM) += platform.o
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
new file mode 100644
index 000000000000..ba58d9253d26
--- /dev/null
+++ b/hw/vfio/migration.c
@@ -0,0 +1,137 @@
+/*
+ * Migration support for VFIO devices
+ *
+ * Copyright NVIDIA, Inc. 2019
+ *
+ * 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"
+
+static void vfio_migration_region_exit(VFIODevice *vbasedev)
+{
+    VFIOMigration *migration = vbasedev->migration;
+
+    if (!migration) {
+        return;
+    }
+
+    if (migration->region.buffer.size) {
+        vfio_region_exit(&migration->region.buffer);
+        vfio_region_finalize(&migration->region.buffer);
+    }
+}
+
+static int vfio_migration_region_init(VFIODevice *vbasedev)
+{
+    VFIOMigration *migration = vbasedev->migration;
+    Object *obj = NULL;
+    int ret = -EINVAL;
+
+    if (!migration) {
+        return ret;
+    }
+
+    /* Migration support added for PCI device only */
+    if (vbasedev->type == VFIO_DEVICE_TYPE_PCI) {
+        obj = vfio_pci_get_object(vbasedev);
+    }
+
+    if (!obj) {
+        return ret;
+    }
+
+    ret = vfio_region_setup(obj, vbasedev, &migration->region.buffer,
+                            migration->region.index, "migration");
+    if (ret) {
+        error_report("Failed to setup VFIO migration region %d: %s",
+                      migration->region.index, strerror(-ret));
+        goto err;
+    }
+
+    if (!migration->region.buffer.size) {
+        ret = -EINVAL;
+        error_report("Invalid region size of VFIO migration region %d: %s",
+                     migration->region.index, strerror(-ret));
+        goto err;
+    }
+
+    return 0;
+
+err:
+    vfio_migration_region_exit(vbasedev);
+    return ret;
+}
+
+static int vfio_migration_init(VFIODevice *vbasedev,
+                               struct vfio_region_info *info)
+{
+    int ret;
+
+    vbasedev->migration = g_new0(VFIOMigration, 1);
+    vbasedev->migration->region.index = info->index;
+
+    ret = vfio_migration_region_init(vbasedev);
+    if (ret) {
+        error_report("Failed to initialise migration region");
+        return ret;
+    }
+
+    return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+int vfio_migration_probe(VFIODevice *vbasedev, Error **errp)
+{
+    struct vfio_region_info *info;
+    int ret;
+
+    ret = vfio_get_dev_region_info(vbasedev, VFIO_REGION_TYPE_MIGRATION,
+                                   VFIO_REGION_SUBTYPE_MIGRATION, &info);
+    if (ret) {
+        Error *local_err = NULL;
+
+        error_setg(&vbasedev->migration_blocker,
+                   "VFIO device doesn't support migration");
+        ret = migrate_add_blocker(vbasedev->migration_blocker, &local_err);
+        if (local_err) {
+            error_propagate(errp, local_err);
+            error_free(vbasedev->migration_blocker);
+            return ret;
+        }
+    } else {
+        return vfio_migration_init(vbasedev, info);
+    }
+
+    return 0;
+}
+
+void vfio_migration_finalize(VFIODevice *vbasedev)
+{
+    if (!vbasedev->migration) {
+        return;
+    }
+
+    if (vbasedev->migration_blocker) {
+        migrate_del_blocker(vbasedev->migration_blocker);
+        error_free(vbasedev->migration_blocker);
+    }
+
+    vfio_migration_region_exit(vbasedev);
+    g_free(vbasedev->migration);
+}
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index ef078cf60ef9..1374a03470d8 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -57,6 +57,15 @@ typedef struct VFIORegion {
     uint8_t nr; /* cache the region number for debug */
 } VFIORegion;
 
+typedef struct VFIOMigration {
+    struct {
+        VFIORegion buffer;
+        uint32_t index;
+    } region;
+    uint64_t pending_bytes;
+    QemuMutex lock;
+} VFIOMigration;
+
 typedef struct VFIOAddressSpace {
     AddressSpace *as;
     QLIST_HEAD(, VFIOContainer) containers;
@@ -118,6 +127,8 @@ typedef struct VFIODevice {
     unsigned int num_irqs;
     unsigned int num_regions;
     unsigned int flags;
+    VFIOMigration *migration;
+    Error *migration_blocker;
 } VFIODevice;
 
 struct VFIODeviceOps {
@@ -206,4 +217,7 @@ int vfio_spapr_create_window(VFIOContainer *container,
 int vfio_spapr_remove_window(VFIOContainer *container,
                              hwaddr offset_within_address_space);
 
+int vfio_migration_probe(VFIODevice *vbasedev, Error **errp);
+void vfio_migration_finalize(VFIODevice *vbasedev);
+
 #endif /* HW_VFIO_VFIO_COMMON_H */
-- 
2.7.0