Re: [dpdk-dev] [PATCH] lib/eal: resolve address conflicts

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 04-Nov-19 6:32 AM, Wangyu (Turing Solution Development Dep) wrote:
> 
> Resolve address conflicts on 64K pagesize without base_virtaddr, which cause new address conflicts in eal_get_virtual_area().
> 
> Signed-off-by: Beard-627 <dengxiaofeng@huawei.com>
> Acked-by: Eric wang <seven.wangyu@huawei.com>
> Acked-by: Wei Hu <xavier.huwei@huawei.com>
> Acked-by: Min Hu <humin29@huawei.com>
> ---
>   lib/librte_eal/linux/eal/eal.c | 22 ++++++++++++++++++++++
>   1 file changed, 22 insertions(+)
> 
> diff --git a/lib/librte_eal/linux/eal/eal.c b/lib/librte_eal/linux/eal/eal.c index 946222c..c15d406 100644
> --- a/lib/librte_eal/linux/eal/eal.c
> +++ b/lib/librte_eal/linux/eal/eal.c
> @@ -360,6 +360,28 @@ enum rte_iova_mode
>   		return -1;
>   	}
>   
> +	if ((getpagesize() == RTE_PGSIZE_64K) &&
> +		(internal_config.base_virtaddr == 0)) {
> +
> +		munmap(rte_mem_cfg_addr, sizeof(*rte_config.mem_config));
> +		rte_mem_cfg_addr = (void *)RTE_PTR_ALIGN_CEIL(
> +			(uintptr_t)rte_mem_cfg_addr, (size_t)RTE_PGSIZE_16M);
> +		rte_mem_cfg_addr = (void *)RTE_ALIGN_FLOOR(
> +			(uintptr_t)rte_mem_cfg_addr -
> +			sizeof(*rte_config.mem_config), sysconf(_SC_PAGE_SIZE));

Please use RTE_PTR_ADD and RTE_PTR_DIFF to perform pointer arithmetic.

> +
> +		rte_mem_cfg_addr = mmap(rte_mem_cfg_addr,
> +			sizeof(*rte_config.mem_config),
> +			PROT_READ | PROT_WRITE, MAP_SHARED, mem_cfg_fd, 0);
> +
> +		if (rte_mem_cfg_addr == MAP_FAILED) {
> +			close(mem_cfg_fd);
> +			mem_cfg_fd = -1;
> +			RTE_LOG(ERR, EAL, "Cannot mmap memory for rte_config\n");
> +			return -1;
> +		}
> +	}
> +
>   	memcpy(rte_mem_cfg_addr, &early_mem_config, sizeof(early_mem_config));
>   	rte_config.mem_config = rte_mem_cfg_addr;
>   
> --
> 1.8.3.1
> 

The patch requires a bit more explanation - what exactly is the problem, 
and why the solution is as above? Also, did you test it on the latest 
master, since the eal_get_virtal_area() patches [1] got merged?

[1] http://patches.dpdk.org/project/dpdk/list/?series=7043&state=*

-- 
Thanks,
Anatoly