| Message ID | 1483969570-3154-2-git-send-email-eric.auger@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 09/01/17 13:45, Eric Auger wrote: > From: Robin Murphy <robin.murphy@arm.com> > > Whilst PCI devices may have 64-bit DMA masks, they still benefit from > using 32-bit addresses wherever possible in order to avoid DAC (PCI) or > longer address packets (PCIe), which may incur a performance overhead. > Implement the same optimisation as other allocators by trying to get a > 32-bit address first, only falling back to the full mask if that fails. Oops, this was just some development work which got promoted to my misc branch for safe keeping; it really has nothing to do with this series. I'd managed to overlook that one of the __alloc_iova() conflicts hit the MSI cookie patch, sorry. Things are now in a more appropriate order in my tree. Robin. > Signed-off-by: Robin Murphy <robin.murphy@arm.com> > --- > drivers/iommu/dma-iommu.c | 21 +++++++++++++++------ > 1 file changed, 15 insertions(+), 6 deletions(-) > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index 2db0d64..a59ca47 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -204,19 +204,28 @@ int dma_direction_to_prot(enum dma_data_direction dir, bool coherent) > } > > static struct iova *__alloc_iova(struct iommu_domain *domain, size_t size, > - dma_addr_t dma_limit) > + dma_addr_t dma_limit, struct device *dev) > { > struct iova_domain *iovad = cookie_iovad(domain); > unsigned long shift = iova_shift(iovad); > unsigned long length = iova_align(iovad, size) >> shift; > + struct iova *iova = NULL; > > if (domain->geometry.force_aperture) > dma_limit = min(dma_limit, domain->geometry.aperture_end); > + > + /* Try to get PCI devices a SAC address */ > + if (dma_limit > DMA_BIT_MASK(32) && dev_is_pci(dev)) > + iova = alloc_iova(iovad, length, DMA_BIT_MASK(32) >> shift, > + true); > /* > * Enforce size-alignment to be safe - there could perhaps be an > * attribute to control this per-device, or at least per-domain... > */ > - return alloc_iova(iovad, length, dma_limit >> shift, true); > + if (!iova) > + iova = alloc_iova(iovad, length, dma_limit >> shift, true); > + > + return iova; > } > > /* The IOVA allocator knows what we mapped, so just unmap whatever that was */ > @@ -369,7 +378,7 @@ struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp, > if (!pages) > return NULL; > > - iova = __alloc_iova(domain, size, dev->coherent_dma_mask); > + iova = __alloc_iova(domain, size, dev->coherent_dma_mask, dev); > if (!iova) > goto out_free_pages; > > @@ -440,7 +449,7 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys, > struct iova_domain *iovad = cookie_iovad(domain); > size_t iova_off = iova_offset(iovad, phys); > size_t len = iova_align(iovad, size + iova_off); > - struct iova *iova = __alloc_iova(domain, len, dma_get_mask(dev)); > + struct iova *iova = __alloc_iova(domain, len, dma_get_mask(dev), dev); > > if (!iova) > return DMA_ERROR_CODE; > @@ -598,7 +607,7 @@ int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg, > prev = s; > } > > - iova = __alloc_iova(domain, iova_len, dma_get_mask(dev)); > + iova = __alloc_iova(domain, iova_len, dma_get_mask(dev), dev); > if (!iova) > goto out_restore_sg; > > @@ -675,7 +684,7 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev, > if (!msi_page) > return NULL; > > - iova = __alloc_iova(domain, iovad->granule, dma_get_mask(dev)); > + iova = __alloc_iova(domain, iovad->granule, dma_get_mask(dev), dev); > if (!iova) > goto out_free_page; > >
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 2db0d64..a59ca47 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -204,19 +204,28 @@ int dma_direction_to_prot(enum dma_data_direction dir, bool coherent) } static struct iova *__alloc_iova(struct iommu_domain *domain, size_t size, - dma_addr_t dma_limit) + dma_addr_t dma_limit, struct device *dev) { struct iova_domain *iovad = cookie_iovad(domain); unsigned long shift = iova_shift(iovad); unsigned long length = iova_align(iovad, size) >> shift; + struct iova *iova = NULL; if (domain->geometry.force_aperture) dma_limit = min(dma_limit, domain->geometry.aperture_end); + + /* Try to get PCI devices a SAC address */ + if (dma_limit > DMA_BIT_MASK(32) && dev_is_pci(dev)) + iova = alloc_iova(iovad, length, DMA_BIT_MASK(32) >> shift, + true); /* * Enforce size-alignment to be safe - there could perhaps be an * attribute to control this per-device, or at least per-domain... */ - return alloc_iova(iovad, length, dma_limit >> shift, true); + if (!iova) + iova = alloc_iova(iovad, length, dma_limit >> shift, true); + + return iova; } /* The IOVA allocator knows what we mapped, so just unmap whatever that was */ @@ -369,7 +378,7 @@ struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp, if (!pages) return NULL; - iova = __alloc_iova(domain, size, dev->coherent_dma_mask); + iova = __alloc_iova(domain, size, dev->coherent_dma_mask, dev); if (!iova) goto out_free_pages; @@ -440,7 +449,7 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys, struct iova_domain *iovad = cookie_iovad(domain); size_t iova_off = iova_offset(iovad, phys); size_t len = iova_align(iovad, size + iova_off); - struct iova *iova = __alloc_iova(domain, len, dma_get_mask(dev)); + struct iova *iova = __alloc_iova(domain, len, dma_get_mask(dev), dev); if (!iova) return DMA_ERROR_CODE; @@ -598,7 +607,7 @@ int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg, prev = s; } - iova = __alloc_iova(domain, iova_len, dma_get_mask(dev)); + iova = __alloc_iova(domain, iova_len, dma_get_mask(dev), dev); if (!iova) goto out_restore_sg; @@ -675,7 +684,7 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev, if (!msi_page) return NULL; - iova = __alloc_iova(domain, iovad->granule, dma_get_mask(dev)); + iova = __alloc_iova(domain, iovad->granule, dma_get_mask(dev), dev); if (!iova) goto out_free_page;