On 2015/5/7 6:18, Bjorn Helgaas wrote: > [+cc Yijing, Dave J, Dave M, Alex] > > On Fri, May 01, 2015 at 01:32:12PM -0500, wdavis@xxxxxxxxxx wrote: >> From: Will Davis <wdavis@xxxxxxxxxx> >> >> Hi, >> >> This patch series adds DMA APIs to map and unmap a struct resource to and from >> a PCI device's IOVA domain, and implements the AMD, Intel, and nommu versions >> of these interfaces. >> >> This solves a long-standing problem with the existing DMA-remapping interfaces, >> which require that a struct page be given for the region to be mapped into a >> device's IOVA domain. This requirement cannot support peer device BAR ranges, >> for which no struct pages exist. >> >> The underlying implementations of map_page and map_sg convert the struct page >> into its physical address anyway, so we just need a way to route the physical >> address of the BAR region to these implementations. The new interfaces do this >> by taking the struct resource describing a device's BAR region, from which the >> physical address is derived. >> >> The Intel and nommu versions have been verified on a dual Intel Xeon E5405 >> workstation. I'm in the process of obtaining hardware to test the AMD version >> as well. Please review. > > I think we currently assume there's no peer-to-peer traffic. > > I don't know whether changing that will break anything, but I'm concerned > about these: > > - PCIe MPS configuration (see pcie_bus_configure_settings()). I think it should be ok for PCIe MPS configuration, PCIE_BUS_PEER2PEER force every device's MPS to 128B, what its concern is the TLP payload size. In this series, it seems to only map a iova for device bar region. > > - PCIe ACS, e.g., pci_acs_enabled(). My guess is that this one is OK, > but Alex would know better. > > - dma_addr_t. Currently dma_addr_t is big enough to hold any address > returned from the DMA API. That's not necessarily big enough to hold a > PCI bus address, e.g., a raw BAR value. > >> Will Davis (6): >> dma-debug: add checking for map/unmap_resource >> DMA-API: Introduce dma_(un)map_resource >> dma-mapping: pci: add pci_(un)map_resource >> iommu/amd: Implement (un)map_resource >> iommu/vt-d: implement (un)map_resource >> x86: add pci-nommu implementation of map_resource >> >> arch/x86/kernel/pci-nommu.c | 17 +++++++ >> drivers/iommu/amd_iommu.c | 76 ++++++++++++++++++++++++++------ >> drivers/iommu/intel-iommu.c | 18 ++++++++ >> include/asm-generic/dma-mapping-broken.h | 9 ++++ >> include/asm-generic/dma-mapping-common.h | 34 ++++++++++++++ >> include/asm-generic/pci-dma-compat.h | 14 ++++++ >> include/linux/dma-debug.h | 20 +++++++++ >> include/linux/dma-mapping.h | 7 +++ >> lib/dma-debug.c | 48 ++++++++++++++++++++ >> 9 files changed, 230 insertions(+), 13 deletions(-) >> >> -- >> 2.3.7 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-pci" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > . > -- Thanks! Yijing -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
