Re: [PATCH for-5.10] swiotlb: remove the tbl_dma_addr argument to swiotlb_tbl_map_single

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Tue, Nov 03, 2020 at 10:46:43AM +0100, Christoph Hellwig wrote:
> ping?

Hopefully this goes through. I am in the process of testing it but ran
into testing issues that I believe are unrelated.


> 
> On Fri, Oct 23, 2020 at 08:33:09AM +0200, Christoph Hellwig wrote:
> > The tbl_dma_addr argument is used to check the DMA boundary for the
> > allocations, and thus needs to be a dma_addr_t.  swiotlb-xen instead
> > passed a physical address, which could lead to incorrect results for
> > strange offsets.  Fix this by removing the parameter entirely and hard
> > code the DMA address for io_tlb_start instead.
> > 
> > Fixes: 91ffe4ad534a ("swiotlb-xen: introduce phys_to_dma/dma_to_phys 
> > translations")
> > Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> > Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> > ---
> >  drivers/iommu/intel/iommu.c |  5 ++---
> >  drivers/xen/swiotlb-xen.c   |  3 +--
> >  include/linux/swiotlb.h     | 10 +++-------
> >  kernel/dma/swiotlb.c        | 16 ++++++----------
> >  4 files changed, 12 insertions(+), 22 deletions(-)
> > 
> > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> > index 8651f6d4dfa032..6b560e6f193096 100644
> > --- a/drivers/iommu/intel/iommu.c
> > +++ b/drivers/iommu/intel/iommu.c
> > @@ -3815,9 +3815,8 @@ bounce_map_single(struct device *dev, phys_addr_t 
> > paddr, size_t size,
> >      * page aligned, we don't need to use a bounce page.
> >      */
> >     if (!IS_ALIGNED(paddr | size, VTD_PAGE_SIZE)) {
> > -           tlb_addr = swiotlb_tbl_map_single(dev,
> > -                           phys_to_dma_unencrypted(dev, io_tlb_start),
> > -                           paddr, size, aligned_size, dir, attrs);
> > +           tlb_addr = swiotlb_tbl_map_single(dev, paddr, size,
> > +                           aligned_size, dir, attrs);
> >             if (tlb_addr == DMA_MAPPING_ERROR) {
> >                     goto swiotlb_error;
> >             } else {
> > diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> > index 71ce1b7a23d1cc..2b385c1b4a99cb 100644
> > --- a/drivers/xen/swiotlb-xen.c
> > +++ b/drivers/xen/swiotlb-xen.c
> > @@ -395,8 +395,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device 
> > *dev, struct page *page,
> >      */
> >     trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
> >  
> > -   map = swiotlb_tbl_map_single(dev, virt_to_phys(xen_io_tlb_start),
> > -                                phys, size, size, dir, attrs);
> > +   map = swiotlb_tbl_map_single(dev, phys, size, size, dir, attrs);
> >     if (map == (phys_addr_t)DMA_MAPPING_ERROR)
> >             return DMA_MAPPING_ERROR;
> >  
> > diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> > index 513913ff748626..3bb72266a75a1d 100644
> > --- a/include/linux/swiotlb.h
> > +++ b/include/linux/swiotlb.h
> > @@ -45,13 +45,9 @@ enum dma_sync_target {
> >     SYNC_FOR_DEVICE = 1,
> >  };
> >  
> > -extern phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
> > -                                     dma_addr_t tbl_dma_addr,
> > -                                     phys_addr_t phys,
> > -                                     size_t mapping_size,
> > -                                     size_t alloc_size,
> > -                                     enum dma_data_direction dir,
> > -                                     unsigned long attrs);
> > +phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t phys,
> > +           size_t mapping_size, size_t alloc_size,
> > +           enum dma_data_direction dir, unsigned long attrs);
> >  
> >  extern void swiotlb_tbl_unmap_single(struct device *hwdev,
> >                                  phys_addr_t tlb_addr,
> > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> > index b4eea0abc3f002..92e2f54f24c01b 100644
> > --- a/kernel/dma/swiotlb.c
> > +++ b/kernel/dma/swiotlb.c
> > @@ -441,14 +441,11 @@ static void swiotlb_bounce(phys_addr_t orig_addr, 
> > phys_addr_t tlb_addr,
> >     }
> >  }
> >  
> > -phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
> > -                              dma_addr_t tbl_dma_addr,
> > -                              phys_addr_t orig_addr,
> > -                              size_t mapping_size,
> > -                              size_t alloc_size,
> > -                              enum dma_data_direction dir,
> > -                              unsigned long attrs)
> > +phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t 
> > orig_addr,
> > +           size_t mapping_size, size_t alloc_size,
> > +           enum dma_data_direction dir, unsigned long attrs)
> >  {
> > +   dma_addr_t tbl_dma_addr = phys_to_dma_unencrypted(hwdev, io_tlb_start);
> >     unsigned long flags;
> >     phys_addr_t tlb_addr;
> >     unsigned int nslots, stride, index, wrap;
> > @@ -667,9 +664,8 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t 
> > paddr, size_t size,
> >     trace_swiotlb_bounced(dev, phys_to_dma(dev, paddr), size,
> >                           swiotlb_force);
> >  
> > -   swiotlb_addr = swiotlb_tbl_map_single(dev,
> > -                   phys_to_dma_unencrypted(dev, io_tlb_start),
> > -                   paddr, size, size, dir, attrs);
> > +   swiotlb_addr = swiotlb_tbl_map_single(dev, paddr, size, size, dir,
> > +                   attrs);
> >     if (swiotlb_addr == (phys_addr_t)DMA_MAPPING_ERROR)
> >             return DMA_MAPPING_ERROR;
> >  
> > -- 
> > 2.28.0
> > 
> > _______________________________________________
> > iommu mailing list
> > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx
> > https://lists.linuxfoundation.org/mailman/listinfo/iommu
> ---end quoted text---