> From: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> > Sent: Thursday, March 2, 2023 9:00 AM > > Global PASID allocation is under IOMMU SVA code since it is the primary > use case. However, some architecture such as VT-d, global PASIDs are > necessary for its internal use of DMA API with PASID. No, global PASID is not a VT-d restriction. It's from ENQCMD/S hence a device requirement. > > This patch introduces SVA APIs to reserve and release global PASIDs. > > Link: https://lore.kernel.org/all/20230301235646.2692846-4- > jacob.jun.pan@xxxxxxxxxxxxxxx/ > Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> > --- > drivers/iommu/iommu-sva.c | 25 +++++++++++++++++++++++++ > include/linux/iommu.h | 14 ++++++++++++++ > 2 files changed, 39 insertions(+) > > diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c > index 8c92a145e15d..cfdeafde88a9 100644 > --- a/drivers/iommu/iommu-sva.c > +++ b/drivers/iommu/iommu-sva.c > @@ -149,6 +149,31 @@ u32 iommu_sva_get_pasid(struct iommu_sva > *handle) > } > EXPORT_SYMBOL_GPL(iommu_sva_get_pasid); > > +ioasid_t iommu_sva_reserve_pasid(ioasid_t min, ioasid_t max) > +{ > + int ret; > + > + if (min == IOMMU_PASID_INVALID || max == > IOMMU_PASID_INVALID || > + min == 0 || max < min) > + return IOMMU_PASID_INVALID; > + > + ret = ida_alloc_range(&iommu_global_pasid_ida, min, max, > GFP_KERNEL); > + if (ret < 0) > + return IOMMU_PASID_INVALID; > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(iommu_sva_reserve_pasid); > + I'm not sure it's the right way. It's not related to SVA. We should move iommu_global_pasid_ida to iomm.c and then have another interface for allocation. Above is pretty generic so probably a general one like: ioasid_t iommu_allocate_global_pasid(struct device *dev) internally it can use [1, dev->iommu->max_pasids] as min/max instead of passed in from the caller.
