Jason Gunthorpe <[email protected]> writes: > On Thu, May 21, 2026 at 09:05:39PM +0530, Aneesh Kumar K.V wrote: >> I am wondering whether this is better >> >> static inline dma_addr_t dma_direct_map_phys(struct device *dev, >> phys_addr_t phys, size_t size, enum dma_data_direction dir, >> unsigned long attrs, bool flush) >> { >> dma_addr_t dma_addr; >> >> /* >> * For a device requiring unencrypted DMA, MMIO memory is treated >> * as shared. >> */ >> if (force_dma_unencrypted(dev) && (attrs & DMA_ATTR_MMIO)) >> attrs |= DMA_ATTR_CC_SHARED; > > It is an option, I would be happier if we went and fixed the few > callers to properly pass the shared. CC did this with the > pgprot_decrypted() stuff, same reasoning: > > diff --git a/block/blk-mq-dma.c b/block/blk-mq-dma.c > index bfdb9ed7074116..e77f6404caa3db 100644 > --- a/block/blk-mq-dma.c > +++ b/block/blk-mq-dma.c > @@ -90,7 +90,7 @@ static bool blk_dma_map_direct(struct request *req, struct > device *dma_dev, > unsigned int attrs = 0; > > if (iter->p2pdma.map == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) > - attrs |= DMA_ATTR_MMIO; > + attrs |= iter->p2pdma.mem->dma_mapping_flags; > > iter->addr = dma_map_phys(dma_dev, vec->paddr, vec->len, > rq_dma_dir(req), attrs); > @@ -115,7 +115,7 @@ static bool blk_rq_dma_map_iova(struct request *req, > struct device *dma_dev, > iter->len = dma_iova_size(state); > > if (iter->p2pdma.map == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) > - attrs |= DMA_ATTR_MMIO; > + attrs |= iter->p2pdma.mem->dma_mapping_flags; > > do { > error = dma_iova_link(dma_dev, state, vec->paddr, mapped, > diff --git a/drivers/dma-buf/dma-buf-mapping.c > b/drivers/dma-buf/dma-buf-mapping.c > index 794acff2546a34..96022fadc48245 100644 > --- a/drivers/dma-buf/dma-buf-mapping.c > +++ b/drivers/dma-buf/dma-buf-mapping.c > @@ -147,7 +147,7 @@ struct sg_table *dma_buf_phys_vec_to_sgt(struct > dma_buf_attachment *attach, > ret = dma_iova_link(attach->dev, dma->state, > phys_vec[i].paddr, 0, > phys_vec[i].len, dir, > - DMA_ATTR_MMIO); > + provider->dma_mapping_flags); > if (ret) > goto err_unmap_dma; > > @@ -155,7 +155,7 @@ struct sg_table *dma_buf_phys_vec_to_sgt(struct > dma_buf_attachment *attach, > } else { > addr = dma_map_phys(attach->dev, phys_vec[i].paddr, > phys_vec[i].len, dir, > - DMA_ATTR_MMIO); > + provider->dma_mapping_flags); > ret = dma_mapping_error(attach->dev, addr); > if (ret) > goto err_unmap_dma; > diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c > index 7c898542af8d5e..e4229b4d35c767 100644 > --- a/drivers/pci/p2pdma.c > +++ b/drivers/pci/p2pdma.c > @@ -282,6 +282,8 @@ int pcim_p2pdma_init(struct pci_dev *pdev) > continue; > > p2p->mem[i].owner = &pdev->dev; > + p2p->mem[i].dma_mapping_flags = > + DMA_ATTR_MMIO | DMA_ATTR_CC_SHARED; > p2p->mem[i].bus_offset = > pci_bus_address(pdev, i) - pci_resource_start(pdev, i); > } > diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h > index 873de20a224759..402dc5e5d62b0a 100644 > --- a/include/linux/pci-p2pdma.h > +++ b/include/linux/pci-p2pdma.h > @@ -21,10 +21,12 @@ struct scatterlist; > * > * A p2pdma provider is a range of MMIO address space available to the CPU. > * @owner: Device to which this provider belongs. > + * @dma_mapping_flags: DMA attributes to use for host bridge mappings. > * @bus_offset: Bus offset for p2p communication. > */ > struct p2pdma_provider { > struct device *owner; > + unsigned long dma_mapping_flags; > u64 bus_offset; > }; > > diff --git a/mm/hmm.c b/mm/hmm.c > index 5955f2f0c83db1..c3f445acddf873 100644 > --- a/mm/hmm.c > +++ b/mm/hmm.c > @@ -811,7 +811,7 @@ dma_addr_t hmm_dma_map_pfn(struct device *dev, struct > hmm_dma_map *map, > case PCI_P2PDMA_MAP_NONE: > break; > case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE: > - attrs |= DMA_ATTR_MMIO; > + attrs |= p2pdma_state->mem->dma_mapping_flags; > pfns[idx] |= HMM_PFN_P2PDMA; > break; > case PCI_P2PDMA_MAP_BUS_ADDR:
Can I convert this as an independent patch with your SOB? -aneesh
