[dpdk-stable] [PATCH v3 1/6] mem: add function for checking memsegs IOVAs addresses

[Eelco Chaudron]

On 4 Jul 2018, at 14:53, Alejandro Lucero wrote:

> A device can suffer addressing limitations. This functions checks
> memsegs have iovas within the supported range based on dma mask.
>
> PMD should use this during initialization if supported devices
> suffer addressing limitations, returning an error if this function
> returns memsegs out of range.
>
> Another potential usage is for emulated IOMMU hardware with addressing
> limitations.
>
> Signed-off-by: Alejandro Lucero <alejandro.lucero at netronome.com>
> Acked-by: Anatoly Burakov <anatoly.burakov at intel.com>
> ---
>  lib/librte_eal/common/eal_common_memory.c  | 33 
> ++++++++++++++++++++++++++++++
>  lib/librte_eal/common/include/rte_memory.h |  3 +++
>  lib/librte_eal/rte_eal_version.map         |  1 +
>  3 files changed, 37 insertions(+)
>
> diff --git a/lib/librte_eal/common/eal_common_memory.c 
> b/lib/librte_eal/common/eal_common_memory.c
> index fc6c44d..f5efebe 100644
> --- a/lib/librte_eal/common/eal_common_memory.c
> +++ b/lib/librte_eal/common/eal_common_memory.c
> @@ -109,6 +109,39 @@
>  	}
>  }
>
> +/* check memseg iovas are within the required range based on dma mask 
> */
> +int
> +rte_eal_check_dma_mask(uint8_t maskbits)
> +{
> +
> +	const struct rte_mem_config *mcfg;
> +	uint64_t mask;
> +	int i;
> +

I think we should add some sanity check to the input maskbits, i.e. 
[64,0) or [64, 32]? What would be a reasonable lower bound.

> +	/* create dma mask */
> +	mask = ~((1ULL << maskbits) - 1);
> +
> +	/* get pointer to global configuration */
> +	mcfg = rte_eal_get_configuration()->mem_config;
> +
> +	for (i = 0; i < RTE_MAX_MEMSEG; i++) {
> +		if (mcfg->memseg[i].addr == NULL)
> +			break;
> +
> +		if (mcfg->memseg[i].iova & mask) {
> +			RTE_LOG(INFO, EAL,
> +				"memseg[%d] iova %"PRIx64" out of range:\n",
> +				i, mcfg->memseg[i].iova);
> +
> +			RTE_LOG(INFO, EAL, "\tusing dma mask %"PRIx64"\n",
> +				mask);
> +			return -1;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
>  /* return the number of memory channels */
>  unsigned rte_memory_get_nchannel(void)
>  {
> diff --git a/lib/librte_eal/common/include/rte_memory.h 
> b/lib/librte_eal/common/include/rte_memory.h
> index 80a8fc0..b2a0168 100644
> --- a/lib/librte_eal/common/include/rte_memory.h
> +++ b/lib/librte_eal/common/include/rte_memory.h
> @@ -209,6 +209,9 @@ struct rte_memseg {
>   */
>  unsigned rte_memory_get_nrank(void);
>
> +/* check memsegs iovas are within a range based on dma mask */
> +int rte_eal_check_dma_mask(uint8_t maskbits);
> +
>  /**
>   * Drivers based on uio will not load unless physical
>   * addresses are obtainable. It is only possible to get
> diff --git a/lib/librte_eal/rte_eal_version.map 
> b/lib/librte_eal/rte_eal_version.map
> index f4f46c1..aa6cf87 100644
> --- a/lib/librte_eal/rte_eal_version.map
> +++ b/lib/librte_eal/rte_eal_version.map
> @@ -184,6 +184,7 @@ DPDK_17.11 {
>
>  	rte_eal_create_uio_dev;
>  	rte_bus_get_iommu_class;
> +	rte_eal_check_dma_mask;
>  	rte_eal_has_pci;
>  	rte_eal_iova_mode;
>  	rte_eal_mbuf_default_mempool_ops;
> -- 
> 1.9.1