Messages in this thread | | | From | "Tian, Kevin" <> | Subject | RE: [PATCH V10 03/11] iommu/vt-d: Add a helper function to skip agaw | Date | Fri, 27 Mar 2020 11:53:42 +0000 |
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> From: Jacob Pan <jacob.jun.pan@linux.intel.com> > Sent: Saturday, March 21, 2020 7:28 AM > > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
could you elaborate in which scenario this helper function is required?
> --- > drivers/iommu/intel-pasid.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/drivers/iommu/intel-pasid.c b/drivers/iommu/intel-pasid.c > index 22b30f10b396..191508c7c03e 100644 > --- a/drivers/iommu/intel-pasid.c > +++ b/drivers/iommu/intel-pasid.c > @@ -500,6 +500,28 @@ int intel_pasid_setup_first_level(struct intel_iommu > *iommu, > } > > /* > + * Skip top levels of page tables for iommu which has less agaw > + * than default. Unnecessary for PT mode. > + */ > +static inline int iommu_skip_agaw(struct dmar_domain *domain, > + struct intel_iommu *iommu, > + struct dma_pte **pgd) > +{ > + int agaw; > + > + for (agaw = domain->agaw; agaw > iommu->agaw; agaw--) { > + *pgd = phys_to_virt(dma_pte_addr(*pgd)); > + if (!dma_pte_present(*pgd)) { > + return -EINVAL; > + } > + } > + pr_debug_ratelimited("%s: pgd: %llx, agaw %d d_agaw %d\n", > __func__, (u64)*pgd, > + iommu->agaw, domain->agaw); > + > + return agaw; > +} > + > +/* > * Set up the scalable mode pasid entry for second only translation type. > */ > int intel_pasid_setup_second_level(struct intel_iommu *iommu, > -- > 2.7.4
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