Messages in this thread | | | Date | Wed, 29 Nov 2023 16:08:34 -0400 | From | Jason Gunthorpe <> | Subject | Re: [PATCH 1/1] iommu/vt-d: Support enforce_cache_coherency only for empty domains |
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On Tue, Nov 14, 2023 at 09:10:33AM +0800, Lu Baolu wrote: > diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h > index 65d37a138c75..ce030c5b5772 100644 > --- a/drivers/iommu/intel/iommu.h > +++ b/drivers/iommu/intel/iommu.h > @@ -602,6 +602,9 @@ struct dmar_domain { > */ > u8 dirty_tracking:1; /* Dirty tracking is enabled */ > u8 nested_parent:1; /* Has other domains nested on it */ > + u8 has_mappings:1; /* Has mappings configured through > + * iommu_map() interface. > + */
Is it racey?
The other option is to make iommfd do this and forbid it from switching the enforce_cache_coherency if the IOAS has any maps attached. We can get the correct locking at that point.
AMD has the same issue if it ever wants to implement its per-PTE bit
Jason
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