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08/09/2023 07:28, Duan, Zhenzhong wrote: > > On 6/23/2023 5:48 AM, Joao Martins wrote: >> Only block the case when the underlying vIOMMU model does not report any >> address space limits, in addition to DMA translation being off or no >> vIOMMU present. The limits are needed such that can define the IOVA limits >> that arm the device dirty tracker. >> >> Additionally, reword the migration blocker error message to clarify that >> we the configured vIOMMU does not support migration, as opposed to >> implying that just being there blocks migration. >> >> Signed-off-by: Joao Martins >> --- >>   hw/vfio/common.c | 7 +++++-- >>   1 file changed, 5 insertions(+), 2 deletions(-) >> >> diff --git a/hw/vfio/common.c b/hw/vfio/common.c >> index 62f91e8e102d..c3cc0dd47044 100644 >> --- a/hw/vfio/common.c >> +++ b/hw/vfio/common.c >> @@ -449,15 +449,18 @@ static int vfio_viommu_get_max_iova(hwaddr *max_iova) >>     int vfio_block_giommu_migration(Error **errp) >>   { >> +    hwaddr max; >>       int ret; >>         if (giommu_migration_blocker || >> -        !vfio_viommu_preset()) { >> +        !vfio_viommu_preset() || >> +        (vfio_viommu_preset() && !vfio_viommu_get_max_iova(&max))) { > > Could be simplified as below: > > +        !vfio_viommu_preset() || !vfio_viommu_get_max_iova(&max))) { > True.