[PATCH v26 07/17] vfio: Register SaveVMHandlers for VFIO device

[Kirti Wankhede]

Define flags to be used as delimeter in migration file stream.
Added .save_setup and .save_cleanup functions. Mapped & unmapped migration
region from these functions at source during saving or pre-copy phase.
Set VFIO device state depending on VM's state. During live migration, VM is
running when .save_setup is called, _SAVING | _RUNNING state is set for VFIO
device. During save-restore, VM is paused, _SAVING state is set for VFIO device.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
---
 hw/vfio/migration.c  | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/vfio/trace-events |  2 ++
 2 files changed, 93 insertions(+)

diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index f650fe9fc3c8..8e8adaa25779 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -8,12 +8,15 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/main-loop.h"
+#include "qemu/cutils.h"
 #include <linux/vfio.h>
 
 #include "sysemu/runstate.h"
 #include "hw/vfio/vfio-common.h"
 #include "cpu.h"
 #include "migration/migration.h"
+#include "migration/vmstate.h"
 #include "migration/qemu-file.h"
 #include "migration/register.h"
 #include "migration/blocker.h"
@@ -25,6 +28,17 @@
 #include "trace.h"
 #include "hw/hw.h"
 
+/*
+ * Flags used as delimiter:
+ * 0xffffffff => MSB 32-bit all 1s
+ * 0xef10     => emulated (virtual) function IO
+ * 0x0000     => 16-bits reserved for flags
+ */
+#define VFIO_MIG_FLAG_END_OF_STATE      (0xffffffffef100001ULL)
+#define VFIO_MIG_FLAG_DEV_CONFIG_STATE  (0xffffffffef100002ULL)
+#define VFIO_MIG_FLAG_DEV_SETUP_STATE   (0xffffffffef100003ULL)
+#define VFIO_MIG_FLAG_DEV_DATA_STATE    (0xffffffffef100004ULL)
+
 static inline int vfio_mig_access(VFIODevice *vbasedev, void *val, int count,
                                   off_t off, bool iswrite)
 {
@@ -166,6 +180,65 @@ static int vfio_migration_set_state(VFIODevice *vbasedev, 
uint32_t mask,
     return 0;
 }
 
+/* ---------------------------------------------------------------------- */
+
+static int vfio_save_setup(QEMUFile *f, void *opaque)
+{
+    VFIODevice *vbasedev = opaque;
+    VFIOMigration *migration = vbasedev->migration;
+    int ret;
+
+    trace_vfio_save_setup(vbasedev->name);
+
+    qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
+
+    if (migration->region.mmaps) {
+        qemu_mutex_lock_iothread();
+        ret = vfio_region_mmap(&migration->region);
+        qemu_mutex_unlock_iothread();
+        if (ret) {
+            error_report("%s: Failed to mmap VFIO migration region %d: %s",
+                         vbasedev->name, migration->region.nr,
+                         strerror(-ret));
+            error_report("%s: Falling back to slow path", vbasedev->name);
+        }
+    }
+
+    ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_MASK,
+                                   VFIO_DEVICE_STATE_SAVING);
+    if (ret) {
+        error_report("%s: Failed to set state SAVING", vbasedev->name);
+        return ret;
+    }
+
+    qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
+
+    ret = qemu_file_get_error(f);
+    if (ret) {
+        return ret;
+    }
+
+    return 0;
+}
+
+static void vfio_save_cleanup(void *opaque)
+{
+    VFIODevice *vbasedev = opaque;
+    VFIOMigration *migration = vbasedev->migration;
+
+    if (migration->region.mmaps) {
+        vfio_region_unmap(&migration->region);
+    }
+    trace_vfio_save_cleanup(vbasedev->name);
+}
+
+static SaveVMHandlers savevm_vfio_handlers = {
+    .save_setup = vfio_save_setup,
+    .save_cleanup = vfio_save_cleanup,
+};
+
+/* ---------------------------------------------------------------------- */
+
 static void vfio_vmstate_change(void *opaque, int running, RunState state)
 {
     VFIODevice *vbasedev = opaque;
@@ -225,6 +298,8 @@ static int vfio_migration_init(VFIODevice *vbasedev,
                                struct vfio_region_info *info)
 {
     int ret = -EINVAL;
+    char id[256] = "";
+    Object *obj;
 
     if (!vbasedev->ops->vfio_get_object) {
         return ret;
@@ -241,6 +316,22 @@ static int vfio_migration_init(VFIODevice *vbasedev,
         return ret;
     }
 
+    obj = vbasedev->ops->vfio_get_object(vbasedev);
+
+    if (obj) {
+        DeviceState *dev = DEVICE(obj);
+        char *oid = vmstate_if_get_id(VMSTATE_IF(dev));
+
+        if (oid) {
+            pstrcpy(id, sizeof(id), oid);
+            pstrcat(id, sizeof(id), "/");
+            g_free(oid);
+        }
+    }
+    pstrcat(id, sizeof(id), "vfio");
+
+    register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1, &savevm_vfio_handlers,
+                         vbasedev);
     vbasedev->vm_state = qemu_add_vm_change_state_handler(vfio_vmstate_change,
                                                           vbasedev);
     vbasedev->migration_state.notify = vfio_migration_state_notifier;
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index bcb3fa7314d7..982d8dccb219 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -152,3 +152,5 @@ vfio_migration_probe(const char *name, uint32_t index) " 
(%s) Region %d"
 vfio_migration_set_state(const char *name, uint32_t state) " (%s) state %d"
 vfio_vmstate_change(const char *name, int running, const char *reason, 
uint32_t dev_state) " (%s) running %d reason %s device state %d"
 vfio_migration_state_notifier(const char *name, const char *state) " (%s) 
state %s"
+vfio_save_setup(const char *name) " (%s)"
+vfio_save_cleanup(const char *name) " (%s)"
-- 
2.7.0