Messages in this thread | | | Subject | Re: [PATCH v2 2/6] iommu/io-pgtable: Allow a pgtable implementation to skip TLB operations | From | Robin Murphy <> | Date | Tue, 7 Jul 2020 12:34:26 +0100 |
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On 2020-06-26 21:04, Jordan Crouse wrote: > Allow a io-pgtable implementation to skip TLB operations by checking for > NULL pointers in the helper functions. It will be up to to the owner > of the io-pgtable instance to make sure that they independently handle > the TLB correctly.
I don't really understand what this is for - tricking the IOMMU driver into not performing its TLB maintenance at points when that maintenance has been deemed necessary doesn't seem like the appropriate way to achieve anything good :/
Robin.
> Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org> > --- > > include/linux/io-pgtable.h | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h > index 53d53c6c2be9..bbed1d3925ba 100644 > --- a/include/linux/io-pgtable.h > +++ b/include/linux/io-pgtable.h > @@ -210,21 +210,24 @@ struct io_pgtable { > > static inline void io_pgtable_tlb_flush_all(struct io_pgtable *iop) > { > - iop->cfg.tlb->tlb_flush_all(iop->cookie); > + if (iop->cfg.tlb) > + iop->cfg.tlb->tlb_flush_all(iop->cookie); > } > > static inline void > io_pgtable_tlb_flush_walk(struct io_pgtable *iop, unsigned long iova, > size_t size, size_t granule) > { > - iop->cfg.tlb->tlb_flush_walk(iova, size, granule, iop->cookie); > + if (iop->cfg.tlb) > + iop->cfg.tlb->tlb_flush_walk(iova, size, granule, iop->cookie); > } > > static inline void > io_pgtable_tlb_flush_leaf(struct io_pgtable *iop, unsigned long iova, > size_t size, size_t granule) > { > - iop->cfg.tlb->tlb_flush_leaf(iova, size, granule, iop->cookie); > + if (iop->cfg.tlb) > + iop->cfg.tlb->tlb_flush_leaf(iova, size, granule, iop->cookie); > } > > static inline void > @@ -232,7 +235,7 @@ io_pgtable_tlb_add_page(struct io_pgtable *iop, > struct iommu_iotlb_gather * gather, unsigned long iova, > size_t granule) > { > - if (iop->cfg.tlb->tlb_add_page) > + if (iop->cfg.tlb && iop->cfg.tlb->tlb_add_page) > iop->cfg.tlb->tlb_add_page(gather, iova, granule, iop->cookie); > } > >
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