Re: [Xen-devel] [PATCH v5 05/30] ARM: GICv3: allocate LPI pending and property table

[Julien Grall <julien.grall@xxxxxxx>]

Hi Andre,

On 06/04/17 00:18, Andre Przywara wrote:
> +static unsigned int max_lpi_bits = 20;
> +integer_param("max_lpi_bits", max_lpi_bits);
> +
> +int gicv3_lpi_init_host_lpis(unsigned int host_lpi_bits)
> +{
> +    /* An implementation needs to support at least 14 bits of LPI IDs. */
> +    max_lpi_bits = max(max_lpi_bits, 14U);
I think we should warn the user if we don't use his command line. He 
might think he can disable LPIs using it.
> +    lpi_data.max_host_lpi_ids = BIT_ULL(min(host_lpi_bits, max_lpi_bits));
> +
> +    /*
> +     * Warn if the number of LPIs are quite high, as the user might not want
> +     * to waste megabytes of memory for a mostly empty table.
> +     * It's very unlikely that we need more than 24 bits worth of LPIs.
> +     */
> +    if ( lpi_data.max_host_lpi_ids > BIT(24) )
> +        warning_add("Using high number of LPIs, limit memory usage with 
> max_lpi_bits\n");
> +
> +    printk("GICv3: using at most %llu LPIs on the host.\n", MAX_NR_HOST_LPIS);
> +
> +    return 0;
> +}
Cheers,

--
Julien Grall

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