[PATCH v18 QEMU 08/18] vfio: Register SaveVMHandlers for VFIO device

[Kirti Wankhede <kwankhede@nvidia.com>]

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  | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/vfio/trace-events |  2 ++
 2 files changed, 81 insertions(+)

diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index c2f5564b51c3..efadc04c9fe7 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -8,12 +8,14 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/main-loop.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"
@@ -24,6 +26,17 @@
 #include "pci.h"
 #include "trace.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 void vfio_migration_region_exit(VFIODevice *vbasedev)
 {
     VFIOMigration *migration = vbasedev->migration;
@@ -126,6 +139,70 @@ 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.index,
+                         strerror(-ret));
+            return ret;
+        }
+    }
+
+    ret = vfio_migration_set_state(vbasedev, ~0, VFIO_DEVICE_STATE_SAVING);
+    if (ret) {
+        error_report("%s: Failed to set state SAVING", vbasedev->name);
+        return ret;
+    }
+
+    /*
+     * Save migration region size. This is used to verify migration region size
+     * is greater than or equal to migration region size at destination
+     */
+    qemu_put_be64(f, migration->region.size);
+
+    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;
@@ -192,6 +269,8 @@ static int vfio_migration_init(VFIODevice *vbasedev,
         return ret;
     }
 
+    register_savevm_live("vfio", VMSTATE_INSTANCE_ID_ANY, 1,
+                         &savevm_vfio_handlers, vbasedev);
     vbasedev->vm_state = qemu_add_vm_change_state_handler(vfio_vmstate_change,
                                                           vbasedev);
 
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index bd3d47b005cb..86c18def016e 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -149,3 +149,5 @@ 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