Alistair Popple <apopple@xxxxxxxxxx> writes: > The invalidate_range() is going to become an architecture specific mmu > notifier used to keep the TLB of secondary MMUs such as an IOMMU in > sync with the CPU page tables. Currently it is called from separate > code paths to the main CPU TLB invalidations. This can lead to a > secondary TLB not getting invalidated when required and makes it hard > to reason about when exactly the secondary TLB is invalidated. > > To fix this move the notifier call to the architecture specific TLB > maintenance functions for architectures that have secondary MMUs > requiring explicit software invalidations. > > This fixes a SMMU bug on ARM64. On ARM64 PTE permission upgrades > require a TLB invalidation. This invalidation is done by the > architecutre specific ptep_set_access_flags() which calls ^ architecture > flush_tlb_page() if required. However this doesn't call the notifier > resulting in infinite faults being generated by devices using the SMMU > if it has previously cached a read-only PTE in it's TLB. > > Moving the invalidations into the TLB invalidation functions ensures > all invalidations happen at the same time as the CPU invalidation. The > architecture specific flush_tlb_all() routines do not call the > notifier as none of the IOMMUs require this. > > Signed-off-by: Alistair Popple <apopple@xxxxxxxxxx> > Suggested-by: Jason Gunthorpe <jgg@xxxxxxxx> > ... > diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c b/arch/powerpc/mm/book3s64/radix_tlb.c > index 0bd4866..9724b26 100644 > --- a/arch/powerpc/mm/book3s64/radix_tlb.c > +++ b/arch/powerpc/mm/book3s64/radix_tlb.c > @@ -752,6 +752,8 @@ void radix__local_flush_tlb_page(struct vm_area_struct *vma, unsigned long vmadd > return radix__local_flush_hugetlb_page(vma, vmaddr); > #endif > radix__local_flush_tlb_page_psize(vma->vm_mm, vmaddr, mmu_virtual_psize); > + mmu_notifier_invalidate_range(vma->vm_mm, vmaddr, > + vmaddr + mmu_virtual_psize); > } > EXPORT_SYMBOL(radix__local_flush_tlb_page); I think we can skip calling the notifier there? It's explicitly a local flush. cheers
