vfio: Add save state functions to SaveVMHandlers

Added .save_live_pending, .save_live_iterate and .save_live_complete_precopy
functions. These functions handles pre-copy and stop-and-copy phase.

In _SAVING|_RUNNING device state or pre-copy phase:
- read pending_bytes. If pending_bytes > 0, go through below steps.
- read data_offset - indicates kernel driver to write data to staging
  buffer.
- read data_size - amount of data in bytes written by vendor driver in
  migration region.
- read data_size bytes of data from data_offset in the migration region.
- Write data packet to file stream as below:
{VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data,
VFIO_MIG_FLAG_END_OF_STATE }

In _SAVING device state or stop-and-copy phase
a. read config space of device and save to migration file stream. This
   doesn't need to be from vendor driver. Any other special config state
   from driver can be saved as data in following iteration.
b. read pending_bytes. If pending_bytes > 0, go through below steps.
c. read data_offset - indicates kernel driver to write data to staging
   buffer.
d. read data_size - amount of data in bytes written by vendor driver in
   migration region.
e. read data_size bytes of data from data_offset in the migration region.
f. Write data packet as below:
   {VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data}
g. iterate through steps b to f while (pending_bytes > 0)
h. Write {VFIO_MIG_FLAG_END_OF_STATE}

When data region is mapped, its user's responsibility to read data from
data_offset of data_size before moving to next steps.

Added fix suggested by Artem Polyakov to reset pending_bytes in
vfio_save_iterate().
Added fix suggested by Zhi Wang to add 0 as data size in migration stream and
add END_OF_STATE delimiter to indicate phase complete.

Suggested-by: Artem Polyakov <artemp@nvidia.com>
Suggested-by: Zhi Wang <zhi.wang.linux@gmail.com>
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index f148b5e828..9f5712dab1 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -153,3 +153,9 @@ vfio_vmstate_change(const char *name, int running, const char *reason, uint32_t
 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)"
+vfio_save_buffer(const char *name, uint64_t data_offset, uint64_t data_size, uint64_t pending) " (%s) Offset 0x%"PRIx64" size 0x%"PRIx64" pending 0x%"PRIx64
+vfio_update_pending(const char *name, uint64_t pending) " (%s) pending 0x%"PRIx64
+vfio_save_device_config_state(const char *name) " (%s)"
+vfio_save_pending(const char *name, uint64_t precopy, uint64_t postcopy, uint64_t compatible) " (%s) precopy 0x%"PRIx64" postcopy 0x%"PRIx64" compatible 0x%"PRIx64
+vfio_save_iterate(const char *name, int data_size) " (%s) data_size %d"
+vfio_save_complete_precopy(const char *name) " (%s)"