Re: [dpdk-dev] [EXT] [PATCH 5/6] build: add option for armv8 crypto extension

[Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>]

> >
> >  CONFIG_RTE_MACHINE="armv8a"
> > +CONFIG_RTE_ENABLE_ARMV8_CRYPTO=y
> 
> This approach is not scalable. Even, it is not good for BlueField as you you
> need to maintain two images.
> 
> Unlike other CPU flags, arm64's crypto cpu flag is really _optional_.
> Access to crypto instructions is always at under runtime check.
> See the following in rte_armv8_pmd.c
> 
> 
> 	/* Check CPU for support for AES instruction set */
> 	if (!rte_cpu_get_flag_enabled(RTE_CPUFLAG_AES)) {
> 		ARMV8_CRYPTO_LOG_ERR(
> 			"AES instructions not supported by CPU");
> 		return -EFAULT;
> 	}
> 
> 	/* Check CPU for support for SHA instruction set */
> 	if (!rte_cpu_get_flag_enabled(RTE_CPUFLAG_SHA1) ||
> 	    !rte_cpu_get_flag_enabled(RTE_CPUFLAG_SHA2)) {
> 		ARMV8_CRYPTO_LOG_ERR(
> 			"SHA1/SHA2 instructions not supported by CPU");
> 		return -EFAULT;
> 	}
> 
> So In order to avoid one more config flags specific to armv8 in meson and
> makefile build infra And avoid the need for 6/6 patch. IMO, # Introduce
> optional CPU flag scheme in eal. Treat armv8 crypto as optional flag # Skip
> the eal init check for optional flag.
> 
> Do you see any issues with that approach?
> 
+1

> 
> 
> 
> 
>