[PATCH v4 12/12] vfio/common: Allow disabling device dirty page tracking

[Joao Martins <joao.m.martins@oracle.com>]

The property 'x-pre-copy-dirty-page-tracking' allows disabling the whole
tracking of VF pre-copy phase of dirty page tracking, though it means
that it will only be used at the start of the switchover phase.

Add an option that disables the VF dirty page tracking, and fall
back into container-based dirty page tracking. This also allows to
use IOMMU dirty tracking even on VFs with their own dirty
tracker scheme.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
---
 include/hw/vfio/vfio-common.h | 1 +
 hw/vfio/common.c              | 3 +++
 hw/vfio/migration.c           | 3 ++-
 hw/vfio/pci.c                 | 3 +++
 4 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 760f31d84ac8..0ed4ebfb4696 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -138,6 +138,7 @@ typedef struct VFIODevice {
     VFIOMigration *migration;
     Error *migration_blocker;
     OnOffAuto pre_copy_dirty_page_tracking;
+    OnOffAuto device_dirty_page_tracking;
     bool dirty_pages_supported;
     bool dirty_tracking;
     HostIOMMUDevice *hiod;
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index cc14f0e3fe24..070a4a2df020 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -199,6 +199,9 @@ bool vfio_devices_all_device_dirty_tracking(const VFIOContainerBase *bcontainer)
     VFIODevice *vbasedev;
 
     QLIST_FOREACH(vbasedev, &bcontainer->device_list, container_next) {
+        if (vbasedev->device_dirty_page_tracking == ON_OFF_AUTO_OFF) {
+            return false;
+        }
         if (!vbasedev->dirty_pages_supported) {
             return false;
         }
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index ce3d1b6e9a25..9b41db367629 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -1036,7 +1036,8 @@ bool vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
         return !vfio_block_migration(vbasedev, err, errp);
     }
 
-    if (!vbasedev->dirty_pages_supported &&
+    if ((!vbasedev->dirty_pages_supported ||
+         vbasedev->device_dirty_page_tracking == ON_OFF_AUTO_OFF) &&
         !vbasedev->bcontainer->dirty_pages_supported) {
         if (vbasedev->enable_migration == ON_OFF_AUTO_AUTO) {
             error_setg(&err,
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 3fc72e898a25..5794d72bd3ab 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3361,6 +3361,9 @@ static Property vfio_pci_dev_properties[] = {
     DEFINE_PROP_ON_OFF_AUTO("x-pre-copy-dirty-page-tracking", VFIOPCIDevice,
                             vbasedev.pre_copy_dirty_page_tracking,
                             ON_OFF_AUTO_ON),
+    DEFINE_PROP_ON_OFF_AUTO("x-device-dirty-page-tracking", VFIOPCIDevice,
+                            vbasedev.device_dirty_page_tracking,
+                            ON_OFF_AUTO_ON),
     DEFINE_PROP_ON_OFF_AUTO("display", VFIOPCIDevice,
                             display, ON_OFF_AUTO_OFF),
     DEFINE_PROP_UINT32("xres", VFIOPCIDevice, display_xres, 0),
-- 
2.17.2