Messages in this thread | | | Subject | Re: [PATCH v2 3/7] iommu/vt-d: Expose ISA direct mapping region via iommu_get_resv_regions | From | Lu Baolu <> | Date | Tue, 26 Mar 2019 09:24:20 +0800 |
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Hi James,
On 3/25/19 8:57 PM, James Sewart wrote: >>> Theres an issue that if we choose to alloc a new resv_region with type >>> IOMMU_RESV_DIRECT, we will need to refactor intel_iommu_put_resv_regions >>> to free this entry type which means refactoring the rmrr regions in >>> get_resv_regions. Should this work be in this patchset? >> Do you mean the rmrr regions are not allocated in get_resv_regions, but >> are freed in put_resv_regions? I think we should fix this in this patch >> set since this might impact the device passthrough if we don't do it. > They’re not allocated and not freed currently, only type IOMMU_RESV_MSI is > freed in put_resv_regions. If we allocate a new resv_region with type > IOMMU_RESV_DIRECT for the isa region, then it won’t be freed. If we modify > put_resv_regions to free type IOMMU_RESV_DIRECT, then we will try to free > the static RMRR regions. > > Either the ISA region is static and not freed as with my implementation, > or the RMRR regions are converted to be allocated on each call to > get_resv_regions and freed in put_resv_regions. >
By the way, there's another way in my mind. Let's add a new region type for LPC devices, e.x. IOMMU_RESV_LPC, and then handle it in the same way as those MSI regions. Just FYI.
Best regards, Lu Baolu
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