Implement 'map_peer_resource' for the Intel IOMMU driver. Simply translate the resource to a physical address and route it to the same handlers used by the 'map_page' API.
This allows a device to map another's resource, to enable peer-to-peer transactions. These functions are guarded behind CONFIG_HAS_DMA_P2P, since the dma_map_ops members are as well. Signed-off-by: Will Davis <[email protected]> Reviewed-by: Terence Ripperda <[email protected]> Reviewed-by: John Hubbard <[email protected]> --- drivers/iommu/intel-iommu.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index a98a7b2..66b371c 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -3544,6 +3544,40 @@ static void intel_unmap_page(struct device *dev, dma_addr_t dev_addr, intel_unmap(dev, dev_addr); } +#ifdef CONFIG_HAS_DMA_P2P +static dma_peer_addr_t intel_map_peer_resource(struct device *dev, + struct device *peer, + struct resource *res, + unsigned long offset, + size_t size, + enum dma_data_direction dir, + struct dma_attrs *attrs) +{ + struct pci_dev *pdev = to_pci_dev(dev); + struct pci_dev *ppeer = to_pci_dev(peer); + struct pci_host_bridge *hbdev = pci_find_host_bridge(pdev->bus); + struct pci_host_bridge *hbpeer = pci_find_host_bridge(ppeer->bus); + + /* + * Disallow the peer-to-peer mapping if the devices do not share a host + * bridge. + */ + if (hbdev != hbpeer) + return 0; + + return __intel_map_single(dev, res->start + offset, size, + dir, *dev->dma_mask); +} + +static void intel_unmap_peer_resource(struct device *dev, + dma_peer_addr_t dev_addr, + size_t size, enum dma_data_direction dir, + struct dma_attrs *attrs) +{ + intel_unmap(dev, dev_addr); +} +#endif + static void *intel_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t flags, struct dma_attrs *attrs) @@ -3700,6 +3734,10 @@ struct dma_map_ops intel_dma_ops = { .unmap_sg = intel_unmap_sg, .map_page = intel_map_page, .unmap_page = intel_unmap_page, +#ifdef CONFIG_HAS_DMA_P2P + .map_peer_resource = intel_map_peer_resource, + .unmap_peer_resource = intel_unmap_peer_resource, +#endif .mapping_error = intel_mapping_error, }; -- 2.4.6 _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
