Messages in this thread | | | Subject | Re: [Linaro-mm-sig] [PATCH v3 1/2] habanalabs: define uAPI to export FD for DMA-BUF | From | Christian König <> | Date | Tue, 22 Jun 2021 17:31:12 +0200 |
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Am 22.06.21 um 17:28 schrieb Jason Gunthorpe: > On Tue, Jun 22, 2021 at 05:24:08PM +0200, Christian König wrote: > >>>> I will take two GAUDI devices and use one as an exporter and one as an >>>> importer. I want to see that the solution works end-to-end, with real >>>> device DMA from importer to exporter. >>> I can tell you it doesn't. Stuffing physical addresses directly into >>> the sg list doesn't involve any of the IOMMU code so any configuration >>> that requires IOMMU page table setup will not work. >> Sure it does. See amdgpu_vram_mgr_alloc_sgt: >> >> amdgpu_res_first(res, offset, length, &cursor); > ^^^^^^^^^^ > > I'm not talking about the AMD driver, I'm talking about this patch. > > + bar_address = hdev->dram_pci_bar_start + > + (pages[cur_page] - prop->dram_base_address); > + sg_dma_address(sg) = bar_address;
Yeah, that is indeed not working.
Oded you need to use dma_map_resource() for this.
Christian.
> > Jason
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