Re: [PATCH v4 2/2] xen/arm: Throw messages for unknown FP/SIMD implement ID

[Bertrand Marquis <Bertrand.Marquis@xxxxxxx>]

> On 25 Aug 2020, at 17:06, Wei Chen <Wei.Chen@xxxxxxx> wrote:
> 
> Arm ID_AA64PFR0_EL1 register provides two fields to describe CPU
> FP/SIMD implementations. Currently, we exactly know the meaning of
> 0x0, 0x1 and 0xf of these fields. Xen treats value < 8 as FP/SIMD
> features presented. If there is a value 0x2 bumped in the future,
> Xen behaviors for value <= 0x1 can also take effect. But what Xen
> done for value <= 0x1 may not always cover new value 0x2 required.
> We throw these messages to break the silence when Xen detected
> unknown FP/SIMD IDs to notice user to check.
> 
> Signed-off-by: Wei Chen <wei.chen@xxxxxxx>

With the small typo after fixed:
Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>

> ---
> xen/arch/arm/setup.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
> 
> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
> index 7968cee47d..6a31eca984 100644
> --- a/xen/arch/arm/setup.c
> +++ b/xen/arch/arm/setup.c
> @@ -133,6 +133,18 @@ static void __init processor_id(void)
>            cpu_has_simd ? " AdvancedSIMD" : "",
>            cpu_has_gicv3 ? " GICv3-SysReg" : "");
> 
> +    /* Warn user if we find unknown floating-point features */
> +    if ( cpu_has_fp && (boot_cpu_feature64(fp) >= 2) )
> +        printk(XENLOG_WARNING "WARNING: Unknown Floating-point ID:%d, "
> +               "this may result to corruption on the platform\n",

s/to/in/

> +               boot_cpu_feature64(fp));
> +
> +    /* Warn user if we find unknown AdvancedSIMD features */
> +    if ( cpu_has_simd && (boot_cpu_feature64(simd) >= 2) )
> +        printk(XENLOG_WARNING "WARNING: Unknown AdvancedSIMD ID:%d, "
> +               "this may result to corruption on the platform\n",

same as upper

> +               boot_cpu_feature64(simd));
> +
>     printk("  Debug Features: %016"PRIx64" %016"PRIx64"\n",
>            boot_cpu_data.dbg64.bits[0], boot_cpu_data.dbg64.bits[1]);
>     printk("  Auxiliary Features: %016"PRIx64" %016"PRIx64"\n",
> -- 
> 2.17.1
>