[dpdk-dev] [PATCH v4] vfio: fix sPAPR IOMMU DMA window size

Burakov, Anatoly anatoly.burakov at intel.com
Tue Aug 8 14:06:12 CEST 2017


> From: Jonas Pfefferle [mailto:jpf at zurich.ibm.com]
> Sent: Tuesday, August 8, 2017 12:17 PM
> To: Burakov, Anatoly <anatoly.burakov at intel.com>
> Cc: dev at dpdk.org; aik at ozlabs.ru; Jonas Pfefferle <jpf at zurich.ibm.com>
> Subject: [PATCH v4] vfio: fix sPAPR IOMMU DMA window size
> 
> DMA window size needs to be big enough to span all memory segment's
> physical addresses. We do not need multiple levels of IOMMU tables as we
> already span ~70TB of physical memory with 16MB hugepages.
> 
> Signed-off-by: Jonas Pfefferle <jpf at zurich.ibm.com>
> ---
> v2:
> * roundup to next power 2 function without loop.
> 
> v3:
> * Replace roundup_next_pow2 with rte_align64pow2
> 
> v4:
> * do not assume ordering of physical addresses of memsegs
> 
>  lib/librte_eal/linuxapp/eal/eal_vfio.c | 20 +++++++++++++++++---
>  1 file changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio.c
> b/lib/librte_eal/linuxapp/eal/eal_vfio.c
> index 946df7e..7d5d61d 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_vfio.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_vfio.c
> @@ -759,10 +759,19 @@ vfio_spapr_dma_map(int vfio_container_fd)
>  		return -1;
>  	}
> 
> -	/* calculate window size based on number of hugepages configured
> */
> -	create.window_size = rte_eal_get_physmem_size();
> +	/* create DMA window from 0 to max(phys_addr + len) */
> +	for (i = 0; i < RTE_MAX_MEMSEG; i++) {
> +		if (ms[i].addr == NULL)
> +			break;
> +
> +		create.window_size = RTE_MAX(create.window_size,
> +				ms[i].phys_addr + ms[i].len);
> +	}
> +
> +	/* sPAPR requires window size to be a power of 2 */
> +	create.window_size = rte_align64pow2(create.window_size);
>  	create.page_shift = __builtin_ctzll(ms->hugepage_sz);
> -	create.levels = 2;
> +	create.levels = 1;
> 
>  	ret = ioctl(vfio_container_fd, VFIO_IOMMU_SPAPR_TCE_CREATE,
> &create);
>  	if (ret) {
> @@ -771,6 +780,11 @@ vfio_spapr_dma_map(int vfio_container_fd)
>  		return -1;
>  	}
> 
> +	if (create.start_addr != 0) {
> +		RTE_LOG(ERR, EAL, "  DMA window start address != 0\n");
> +		return -1;
> +	}
> +
>  	/* map all DPDK segments for DMA. use 1:1 PA to IOVA mapping */
>  	for (i = 0; i < RTE_MAX_MEMSEG; i++) {
>  		struct vfio_iommu_type1_dma_map dma_map;
> --
> 2.7.4

Acked by: Anatoly Burakov <anatoly.burakov at intel.com>

Thanks,
Anatoly


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