Re: [Xen-devel] [PATCH v2 2/2] xen/arm: GICv3: Only initialize ITS when the distributor supports LPIs.

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 24 Jan 2018, Julien Grall wrote:
> There are firmware tables out describing the ITS but does not support
> LPIs. This will result to a data abort when trying to initialize ITS.
> 
> While this can be consider a bug in the Device-Tree, same configuration
> boots on Linux. So gate the ITS initialization with the support of LPIs
> in the distributor.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>

> ---
>  xen/arch/arm/gic-v3.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
> index 9f9cf59f82..730450e34b 100644
> --- a/xen/arch/arm/gic-v3.c
> +++ b/xen/arch/arm/gic-v3.c
> @@ -1637,6 +1637,11 @@ static unsigned long 
> gicv3_get_hwdom_extra_madt_size(const struct domain *d)
>  }
>  #endif
>  
> +static bool gic_dist_supports_lpis(void)
> +{
> +    return (readl_relaxed(GICD + GICD_TYPER) & GICD_TYPE_LPIS);
> +}
> +
>  /* Set up the GIC */
>  static int __init gicv3_init(void)
>  {
> @@ -1699,9 +1704,12 @@ static int __init gicv3_init(void)
>  
>      gicv3_dist_init();
>  
> -    res = gicv3_its_init();
> -    if ( res )
> -        panic("GICv3: ITS: initialization failed: %d\n", res);
> +    if ( gic_dist_supports_lpis() )
> +    {
> +        res = gicv3_its_init();
> +        if ( res )
> +            panic("GICv3: ITS: initialization failed: %d\n", res);
> +    }
>  
>      res = gicv3_cpu_init();
>      if ( res )
> -- 
> 2.11.0
> 

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