Re: [dpdk-dev] [dpdk-stable] [PATCH 1/2] mempool: use actual IOVA addresses when populating

["Li, WenjieX A" <wenjiex.a.li@intel.com>]

Tested-by: Chen, BoX C <box.c.chen@intel.com>

> -----Original Message-----
> From: stable [mailto:stable-bounces@dpdk.org] On Behalf Of Anatoly Burakov
> Sent: Thursday, November 14, 2019 9:58 PM
> To: dev@dpdk.org
> Cc: Olivier Matz <olivier.matz@6wind.com>; Andrew Rybchenko
> <arybchenko@solarflare.com>; david.marchand@redhat.com; stable@dpdk.org
> Subject: [dpdk-stable] [PATCH 1/2] mempool: use actual IOVA addresses when
> populating
> 
> Currently, when mempool is being populated, we get IOVA address of every
> segment using rte_mem_virt2iova(). This works for internal memory, but does
> not really work for external memory, and does not work on platforms which
> return RTE_BAD_IOVA as a result of this call (such as FreeBSD). Moreover, even
> when it works, the function in question will do unnecessary pagewalks in IOVA
> as PA mode, as it falls back to rte_mem_virt2phy() instead of just doing a lookup
> in internal memseg table.
> 
> To fix it, replace the call to first attempt to look through the internal memseg
> table (this takes care of internal and external memory), and fall back to
> rte_mem_virt2iova() when unable to perform VA->IOVA translation via memseg
> table.
> 
> Fixes: 66cc45e293ed ("mem: replace memseg with memseg lists")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
> ---
>  lib/librte_mempool/rte_mempool.c | 17 +++++++++++++++--
>  1 file changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/librte_mempool/rte_mempool.c
> b/lib/librte_mempool/rte_mempool.c
> index 40cae3eb67..8da2e471c7 100644
> --- a/lib/librte_mempool/rte_mempool.c
> +++ b/lib/librte_mempool/rte_mempool.c
> @@ -356,6 +356,19 @@ rte_mempool_populate_iova(struct rte_mempool *mp,
> char *vaddr,
>  	return ret;
>  }
> 
> +static rte_iova_t
> +get_iova(void *addr)
> +{
> +	struct rte_memseg *ms;
> +
> +	/* try registered memory first */
> +	ms = rte_mem_virt2memseg(addr, NULL);
> +	if (ms == NULL || ms->iova == RTE_BAD_IOVA)
> +		/* fall back to actual physical address */
> +		return rte_mem_virt2iova(addr);
> +	return ms->iova + RTE_PTR_DIFF(addr, ms->addr); }
> +
>  /* Populate the mempool with a virtual area. Return the number of
>   * objects added, or a negative value on error.
>   */
> @@ -375,7 +388,7 @@ rte_mempool_populate_virt(struct rte_mempool *mp,
> char *addr,
>  	for (off = 0; off < len &&
>  		     mp->populated_size < mp->size; off += phys_len) {
> 
> -		iova = rte_mem_virt2iova(addr + off);
> +		iova = get_iova(addr + off);
> 
>  		if (iova == RTE_BAD_IOVA && rte_eal_has_hugepages()) {
>  			ret = -EINVAL;
> @@ -391,7 +404,7 @@ rte_mempool_populate_virt(struct rte_mempool *mp,
> char *addr,
>  		     phys_len = RTE_MIN(phys_len + pg_sz, len - off)) {
>  			rte_iova_t iova_tmp;
> 
> -			iova_tmp = rte_mem_virt2iova(addr + off + phys_len);
> +			iova_tmp = get_iova(addr + off + phys_len);
> 
>  			if (iova_tmp == RTE_BAD_IOVA ||
>  					iova_tmp != iova + phys_len)
> --
> 2.17.1