[PATCH RFCv2 8/8] vfio/common: Allow disabling device dirty page tracking

[Joao Martins]

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>
---
 hw/vfio/common.c              | 7 +++++++
 hw/vfio/migration.c           | 3 ++-
 hw/vfio/pci.c                 | 3 +++
 include/hw/vfio/vfio-common.h | 1 +
 4 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index a940c0b6ede8..9fe113ea016d 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -213,6 +213,9 @@ 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;
         }
@@ -236,6 +239,10 @@ bool vfio_device_dirty_pages_supported(VFIODevice 
*vbasedev)
         return false;
     }
 
+    if (vbasedev->device_dirty_page_tracking == ON_OFF_AUTO_OFF) {
+        return false;
+    }
+
     return !vbasedev->dirty_pages_supported;
 }
 
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 674e76b3f3df..09e742fbeb9f 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -938,7 +938,8 @@ 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->iommufd_dev.iommufd &&
          !iommufd_dirty_pages_supported(&vbasedev->iommufd_dev, &err))) {
         if (vbasedev->enable_migration == ON_OFF_AUTO_AUTO) {
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index dedb64fc080e..d3b516b2e4d3 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3349,6 +3349,9 @@ 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),
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index a3e691c126c6..e67f5e74cebd 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -136,6 +136,7 @@ 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;
     union {
-- 
2.39.3