RE: [PATCH v4 11/12] vfio/migration: Don't block migration device dirty tracking is unsupported

[Duan, Zhenzhong]

>-----Original Message-----
>From: Joao Martins <joao.m.martins@oracle.com>
>Subject: [PATCH v4 11/12] vfio/migration: Don't block migration device dirty
>tracking is unsupported
>
>By default VFIO migration is set to auto, which will support live
>migration if the migration capability is set *and* also dirty page
>tracking is supported.
>
>For testing purposes one can force enable without dirty page tracking
>via enable-migration=on, but that option is generally left for testing
>purposes.
>
>So starting with IOMMU dirty tracking it can use to acomodate the lack of
>VF dirty page tracking allowing us to minimize the VF requirements for
>migration and thus enabling migration by default for those too.
>
>Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
>---
> hw/vfio/migration.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
>diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
>index 34d4be2ce1b1..ce3d1b6e9a25 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->bcontainer->dirty_pages_supported) {
>         if (vbasedev->enable_migration == ON_OFF_AUTO_AUTO) {
>             error_setg(&err,
>                        "%s: VFIO device doesn't support device dirty 
> tracking",

I'm not sure if this message needs to be updated, " VFIO device doesn't support 
device and IOMMU dirty tracking"

Same for the below:

warn_report("%s: VFIO device doesn't support device dirty tracking"