Messages in this thread | | | Subject | Re: [PATCH] iommu/vt-d: Return the correct dma mask when we are bypassing the IOMMU | From | Lu Baolu <> | Date | Thu, 10 Oct 2019 09:26:37 +0800 |
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Hi,
On 10/8/19 10:33 PM, Arvind Sankar wrote: > We must return a mask covering the full physical RAM when bypassing the > IOMMU mapping. Also, in iommu_need_mapping, we need to check using > dma_direct_get_required_mask to ensure that the device's dma_mask can > cover physical RAM before deciding to bypass IOMMU mapping. > > Fixes: 249baa547901 ("dma-mapping: provide a better default ->get_required_mask") > Reported-by: Arvind Sankar <nivedita@alum.mit.edu> > Tested-by: Arvind Sankar <nivedita@alum.mit.edu> > Originally-by: Christoph Hellwig <hch@lst.de> > Signed-off-by: Christoph Hellwig <hch@lst.de> > Fixed-by: Arvind Sankar <nivedita@alum.mit.edu> > Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
This patch looks good to me.
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
> --- > drivers/iommu/intel-iommu.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index 3f974919d3bd..79e35b3180ac 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -3471,7 +3471,7 @@ static bool iommu_need_mapping(struct device *dev) > if (dev->coherent_dma_mask && dev->coherent_dma_mask < dma_mask) > dma_mask = dev->coherent_dma_mask; > > - if (dma_mask >= dma_get_required_mask(dev)) > + if (dma_mask >= dma_direct_get_required_mask(dev)) > return false; > > /* > @@ -3775,6 +3775,13 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele > return nelems; > } > > +static u64 intel_get_required_mask(struct device *dev) > +{ > + if (!iommu_need_mapping(dev)) > + return dma_direct_get_required_mask(dev); > + return DMA_BIT_MASK(32); > +} > + > static const struct dma_map_ops intel_dma_ops = { > .alloc = intel_alloc_coherent, > .free = intel_free_coherent, > @@ -3787,6 +3794,7 @@ static const struct dma_map_ops intel_dma_ops = { > .dma_supported = dma_direct_supported, > .mmap = dma_common_mmap, > .get_sgtable = dma_common_get_sgtable, > + .get_required_mask = intel_get_required_mask, > }; > > static void >
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