vfio/migration: Implement VFIO migration protocol v2

Implement the basic mandatory part of VFIO migration protocol v2.
This includes all functionality that is necessary to support
VFIO_MIGRATION_STOP_COPY part of the v2 protocol.

The two protocols, v1 and v2, will co-exist and in the following patches
v1 protocol code will be removed.

There are several main differences between v1 and v2 protocols:
- VFIO device state is now represented as a finite state machine instead
  of a bitmap.

- Migration interface with kernel is now done using VFIO_DEVICE_FEATURE
  ioctl and normal read() and write() instead of the migration region.

- Pre-copy is made optional in v2 protocol. Support for pre-copy will be
  added later on.

Detailed information about VFIO migration protocol v2 and its difference
compared to v1 protocol can be found here [1].

[1]
https://lore.kernel.org/all/20220224142024.147653-10-yishaih@nvidia.com/

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>.
Link: https://lore.kernel.org/r/20230216143630.25610-9-avihaih@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 15 insertions, 2 deletions

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 1c974e9c5a..54fee2d5de 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -408,10 +408,17 @@ static bool vfio_devices_all_dirty_tracking(VFIOContainer *container)
                 return false;
             }
 
-            if ((vbasedev->pre_copy_dirty_page_tracking == ON_OFF_AUTO_OFF) &&
+            if (!migration->v2 &&
+                (vbasedev->pre_copy_dirty_page_tracking == ON_OFF_AUTO_OFF) &&
                 (migration->device_state_v1 & VFIO_DEVICE_STATE_V1_RUNNING)) {
                 return false;
             }
+
+            if (migration->v2 &&
+                vbasedev->pre_copy_dirty_page_tracking == ON_OFF_AUTO_OFF &&
+                migration->device_state == VFIO_DEVICE_STATE_RUNNING) {
+                return false;
+            }
         }
     }
     return true;
@@ -438,7 +445,13 @@ static bool vfio_devices_all_running_and_mig_active(VFIOContainer *container)
                 return false;
             }
 
-            if (migration->device_state_v1 & VFIO_DEVICE_STATE_V1_RUNNING) {
+            if (!migration->v2 &&
+                migration->device_state_v1 & VFIO_DEVICE_STATE_V1_RUNNING) {
+                continue;
+            }
+
+            if (migration->v2 &&
+                migration->device_state == VFIO_DEVICE_STATE_RUNNING) {
                 continue;
             } else {
                 return false;