[dpdk-dev] [PATCH v4 0/6] introduce DMA memory mapping for external memory
gaetan.rivet at 6wind.com
Mon Mar 11 10:27:38 CET 2019
Thanks for taking my remarks into account. You can add my acked-by if
you need to the series (not really for mlx5 PMD but you get the idea).
On Sun, Mar 10, 2019 at 10:27:57AM +0200, Shahaf Shuler wrote:
> The DPDK APIs expose 3 different modes to work with memory used for DMA:
> 1. Use the DPDK owned memory (backed by the DPDK provided hugepages).
> This memory is allocated by the DPDK libraries, included in the DPDK
> memory system (memseg lists) and automatically DMA mapped by the DPDK
> 2. Use memory allocated by the user and register to the DPDK memory
> systems. Upon registration of memory, the DPDK layers will DMA map it
> to all needed devices. After registration, allocation of this memory
> will be done with rte_*malloc APIs.
> 3. Use memory allocated by the user and not registered to the DPDK memory
> system. This is for users who wants to have tight control on this
> memory (e.g. avoid the rte_malloc header).
> The user should create a memory, register it through rte_extmem_register
> API, and call DMA map function in order to register such memory to
> the different devices.
> The scope of the patch focus on #3 above.
> Currently the only way to map external memory is through VFIO
> (rte_vfio_dma_map). While VFIO is common, there are other vendors
> which use different ways to map memory (e.g. Mellanox and NXP).
> The work in this patch moves the DMA mapping to vendor agnostic APIs.
> Device level DMA map and unmap APIs were added. Implementation of those
> APIs was done currently only for PCI devices.
> For PCI bus devices, the pci driver can expose its own map and unmap
> functions to be used for the mapping. In case the driver doesn't provide
> any, the memory will be mapped, if possible, to IOMMU through VFIO APIs.
> Application usage with those APIs is quite simple:
> * allocate memory
> * call rte_extmem_register on the memory chunk.
> * take a device, and query its rte_device.
> * call the device specific mapping function for this device.
> Future work will deprecate the rte_vfio_dma_map and rte_vfio_dma_unmap
> APIs, leaving the rte device APIs as the preferred option for the user.
> On v4:
> - Changed rte_dev_dma_map errno to ENOTSUP in case bus doesn't support
> DMA map API.
> On v3:
> - Fixed compilation issue on freebsd.
> - Fixed forgotten rte_bus_dma_map to rte_dev_dma_map.
> - Removed __rte_deprecated from vfio function till the time the rte_dev_dma_map
> will be non-experimental.
> - Changed error return value to always be -1, with proper errno.
> - Used rte_mem_virt2memseg_list instead of rte_mem_virt2memseg to verify
> memory is registered.
> - Added above check also on dma_unmap calls.
> - Added note in the API the memory must be registered in advance.
> - Added debug log to report the case memory mapping to vfio was skipped.
> On v2:
> - Added warn in release notes about the API change in vfio.
> - Moved function doc to prototype declaration.
> - Used dma_map and dma_unmap instead of map and unmap.
> - Used RTE_VFIO_DEFAULT_CONTAINER_FD instead of -1 fixed value.
> - Moved bus function to eal_common_dev.c and renamed them properly.
> - Changed eth device iterator to use RTE_DEV_FOREACH.
> - Enforced memory is registered with rte_extmem_* prior to mapping.
> - Used EEXIST as the only possible return value from type1 vfio IOMMU mapping.
>  https://patches.dpdk.org/patch/47796/
> Shahaf Shuler (6):
> vfio: allow DMA map of memory for the default vfio fd
> vfio: don't fail to DMA map if memory is already mapped
> bus: introduce device level DMA memory mapping
> net/mlx5: refactor external memory registration
> net/mlx5: support PCI device DMA map and unmap
> doc: deprecation notice for VFIO DMA map APIs
> doc/guides/prog_guide/env_abstraction_layer.rst | 2 +-
> doc/guides/rel_notes/deprecation.rst | 4 +
> doc/guides/rel_notes/release_19_05.rst | 3 +
> drivers/bus/pci/pci_common.c | 48 ++++
> drivers/bus/pci/rte_bus_pci.h | 40 ++++
> drivers/net/mlx5/mlx5.c | 2 +
> drivers/net/mlx5/mlx5_mr.c | 225 ++++++++++++++++---
> drivers/net/mlx5/mlx5_rxtx.h | 5 +
> lib/librte_eal/common/eal_common_dev.c | 34 +++
> lib/librte_eal/common/include/rte_bus.h | 44 ++++
> lib/librte_eal/common/include/rte_dev.h | 47 ++++
> lib/librte_eal/common/include/rte_vfio.h | 8 +-
> lib/librte_eal/linuxapp/eal/eal_vfio.c | 42 +++-
> lib/librte_eal/rte_eal_version.map | 2 +
> 14 files changed, 468 insertions(+), 38 deletions(-)
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