Re: [dpdk-dev] [PATCH v2 1/3] eal/freebsd: fix IOVA mode selection

[Bruce Richardson <bruce.richardson@intel.com>]

On Mon, Nov 01, 2021 at 09:36:59AM +0200, Dmitry Kozlyuk wrote:
> FreeBSD EAL selected IOVA mode PA even in --no-huge mode
> where PA are not available. Memory zones were created with IOVA
> equal to RTE_BAD_IOVA with no indication this field is not usable.
> 
> Change IOVA mode detection:
> 1. Always allow to force --iova-mode=va.
> 2. In --no-huge mode, disallow forcing --iova-mode=pa, and select VA.
> 3. Otherwise select IOVA mode according to bus requests, default to PA.
> In case contigmem is inaccessible, memory initialization will fail
> with a message indicating the cause.
> 
> Fixes: c2361bab70c5 ("eal: compute IOVA mode based on PA availability")
> Cc: benjamin.walker@intel.com
> Cc: stable@dpdk.org
> 
> Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
> ---
>  lib/eal/freebsd/eal.c | 37 +++++++++++++++++++++++++------------
>  1 file changed, 25 insertions(+), 12 deletions(-)
> 
> diff --git a/lib/eal/freebsd/eal.c b/lib/eal/freebsd/eal.c
> index 9935356ed4..519a645344 100644
> --- a/lib/eal/freebsd/eal.c
> +++ b/lib/eal/freebsd/eal.c
> @@ -677,6 +677,8 @@ rte_eal_init(int argc, char **argv)
>  	const struct rte_config *config = rte_eal_get_configuration();
>  	struct internal_config *internal_conf =
>  		eal_get_internal_configuration();
> +	bool has_phys_addr;
> +	enum rte_iova_mode iova_mode;
>  
>  	/* checks if the machine is adequate */
>  	if (!rte_cpu_is_supported()) {
> @@ -777,21 +779,32 @@ rte_eal_init(int argc, char **argv)
>  		return -1;
>  	}
>  
> -	/* if no EAL option "--iova-mode=<pa|va>", use bus IOVA scheme */
> -	if (internal_conf->iova_mode == RTE_IOVA_DC) {
> -		/* autodetect the IOVA mapping mode (default is RTE_IOVA_PA) */
> -		enum rte_iova_mode iova_mode = rte_bus_get_iommu_class();
> -
> -		if (iova_mode == RTE_IOVA_DC)
> -			iova_mode = RTE_IOVA_PA;
> -		rte_eal_get_configuration()->iova_mode = iova_mode;
> -	} else {
> -		rte_eal_get_configuration()->iova_mode =
> -			internal_conf->iova_mode;
> +	/*
> +	 * PA are only available for hugepages via contigmem.
> +	 * If contigmem is inaccessible, rte_eal_hugepage_init() will fail
> +	 * with a message describing the cause.
> +	 */
> +	has_phys_addr = internal_conf->no_hugetlbfs == 0;
> +	iova_mode = internal_conf->iova_mode;
> +	if (iova_mode == RTE_IOVA_PA && !has_phys_addr) {
> +		rte_eal_init_alert("Cannot use IOVA as 'PA' since physical addresses are not available");
> +		rte_errno = EINVAL;
> +		return -1;
> +	}
> +	if (iova_mode == RTE_IOVA_DC) {
> +		RTE_LOG(DEBUG, EAL, "Specific IOVA mode is not requested, autodetecting\n");
> +		if (has_phys_addr) {
> +			RTE_LOG(DEBUG, EAL, "Selecting IOVA mode according to bus requests\n");
> +			iova_mode = rte_bus_get_iommu_class();
> +			if (iova_mode == RTE_IOVA_DC)
> +				iova_mode = RTE_IOVA_PA;
> +		} else {
> +			iova_mode = RTE_IOVA_VA;
> +		}
>  	}
> -
>  	RTE_LOG(INFO, EAL, "Selected IOVA mode '%s'\n",
>  		rte_eal_iova_mode() == RTE_IOVA_PA ? "PA" : "VA");
> +	rte_eal_get_configuration()->iova_mode = iova_mode;
>  

This line needs to come before the log, or else the log statement needs to
be changed to use iova_mode rather than rte_eal_iova_mode(). I'd suggest
the former option.

With that change, you can add my ack to v2:

Acked-by: Bruce Richardson <bruce.richardson@intel.com>