Re: [dpdk-dev] [PATCH 2/4] eal: do not use physical addresses in IOVA as VA mode

[santosh <santosh.shukla@caviumnetworks.com>]

On Sunday 01 April 2018 05:56 PM, Anatoly Burakov wrote:
> We already use VA addresses for IOVA purposes everywhere if we're in
> RTE_IOVA_VA mode:
>  1) rte_malloc_virt2phy()/rte_malloc_virt2iova() always return VA addresses
>  2) Because of 1), memzone's IOVA is set to VA address on reserve
>  3) Because of 2), mempool's IOVA addresses are set to VA addresses
>
> The only place where actual physical addresses are stored is in memsegs at
> init time, but we're not using them anywhere, and there is no external API
> to get those addresses (aside from manually iterating through memsegs), nor
> should anyone care about them in RTE_IOVA_VA mode.
>
> So, fix EAL initialization to allocate VA-contiguous segments at the start
> without regard for physical addresses (as if they weren't available), and
> use VA to set final IOVA addresses for all pages.
>
> Fixes: 62196f4e0941 ("mem: rename address mapping function to IOVA")
> Cc: thomas@monjalon.net
> Cc: stable@dpdk.org
>
> Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
> ---
>  lib/librte_eal/linuxapp/eal/eal_memory.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
> index 38853b7..ecf375b 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_memory.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
> @@ -473,6 +473,9 @@ map_all_hugepages(struct hugepage_file *hugepg_tbl, struct hugepage_info *hpi,
>  			hugepg_tbl[i].orig_va = virtaddr;
>  		}
>  		else {
> +			/* rewrite physical addresses in IOVA as VA mode */
> +			if (rte_eal_iova_mode() == RTE_IOVA_VA)
> +				hugepg_tbl[i].physaddr = (uintptr_t)virtaddr;
>  			hugepg_tbl[i].final_va = virtaddr;
>  		}
>  
> @@ -1091,7 +1094,8 @@ rte_eal_hugepage_init(void)
>  				continue;
>  		}
>  
> -		if (phys_addrs_available) {
> +		if (phys_addrs_available &&
> +				rte_eal_iova_mode() != RTE_IOVA_VA) {

Also can be done like below:
if (phys_addrs_available)
	/* find physical addresses for each hugepage */
	if (find_iovaaddrs(&tmp_hp[hp_offset], hpi) < 0) {

such that;
find_iovaaddrs() --> rte_mem_virt2iova().

That way avoid iova check in above if loop.
does that make sense?
Thanks.
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