Messages in this thread | | | Date | Mon, 22 Aug 2022 15:31:20 -0700 | Subject | Re: [PATCH 2/2] iommu: Use the user PGD for SVA if PTI is enabled | From | Dave Hansen <> |
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On 8/22/22 13:12, Jacob Pan wrote: > @@ -394,7 +395,9 @@ static struct iommu_sva *intel_svm_bind_mm(struct intel_iommu *iommu, > sflags = (flags & SVM_FLAG_SUPERVISOR_MODE) ? > PASID_FLAG_SUPERVISOR_MODE : 0; > sflags |= cpu_feature_enabled(X86_FEATURE_LA57) ? PASID_FLAG_FL5LP : 0; > - ret = intel_pasid_setup_first_level(iommu, dev, mm->pgd, mm->pasid, > + > + pgd = static_cpu_has(X86_FEATURE_PTI) ? kernel_to_user_pgdp(mm->pgd) : mm->pgd; > + ret = intel_pasid_setup_first_level(iommu, dev, pgd, mm->pasid, > FLPT_DEFAULT_DID, sflags);
This X86_FEATURE_PTI should really be done within a helper.
I'd probably do this with a *new* helper since all of the existing kernel_to_user_pgdp() users seem to be within a PTI #ifdef.
Maybe something like:
pgd_t *mm_user_pgd(struct mm_struct *mm) { #ifdef CONFIG_PAGE_TABLE_ISOLATION if (cpu_feature_enabled(X86_FEATURE_PTI)) return kernel_to_user_pgdp(mm->pgd); #endif return mm->pgd; }
That #ifdef could even go away if your kernel_to_user_pgdp() stub from patch 1/2 was available. I'm not sure it's worth it though.
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