Re: [dpdk-users] Attatching global memory pointer to mbuf and sending it to ethernet port.

[Stephen Hemminger <stephen@networkplumber.org>]

On Fri, 3 Jan 2020 09:11:46 +0900
JeongHwan Kim <kjh.kernel.kr@gmail.com> wrote:

> Hi, everyone
> 
> I'd like to send the contents of global memory through ethernet port
> without memory copying to mbuf.
> So, I attached the pointer of global memory to mbuf's buffer address, but
> segfault occurs when I send it to ethernet port.
> I 'm using dpdk version 2019.11  and eal config with   "--iova-mode=pa"
> option.
> My hw platform is NXP ls2088a.
> 
> My routine is like this:
> 
> int buf_len = 100;
> struct rte_mbuf *m = rte_pktmbuf_alloc(mbuf_pool);
> struct rte_mbuf_ext_shared_info *shinfo =
> rte_pktmbuf_ext_shinfo_init_helper(buf_addr, &buf_len,  free_cb, fcb_arg);
> rte_pktmbuf_attach_extbuf(m, buf_addr, buf_iova, buf_len, shinfo);
> rte_pktmbuf_reset_headroom(m);
> ...
> and sent  "m"  to ethernet, the result was
> 
> Thread 4 "lcore-slave-1" received signal SIGSEGV, Segmentation fault.
> [Switching to Thread 0xffffbdb0c910 (LWP 10614)]
> 0x0000aaaaaab73f58 in eth_mbuf_to_sg_fd ()
> 
> The buffer was created as follows :
> user_mz = rte_memzone_reserve_aligned("user_mz", size, rte_socket_id(),
>                     RTE_MEMZONE_1GB|RTE_MEMZONE_IOVA_CONTIG,
>                     RTE_CACHE_LINE_SIZE);
> buf_addr = user_mz->addr;
> buf_iova = user_mz->iova;
> 
> Please give me a hint for this problem.
> Thanks in advance.
> 
> Jeong-Hwa Kim.

Are you using primary/secondary process model?
Is the memory zone being created in the primary process?