Re: [Xen-devel] [PATCH 1/8] xen/arm: acpi: Handle correctly detection of GICv2 on GICv3

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Fri, 3 Feb 2017, Julien Grall wrote:
> When the GICv3 is not GICv2 compatible, the associated field in the MADT
> will be zeroed. However, the rest of the code expects the variable to
> be set to INVALID_PADDR.
> 
> This will result to false detection of GICv2 and give I/O access to page
> 0 for the hardware domain.
> 
> Thankfully, it will fail because the size of GICV has not been set.
> 
> Fix the detection by converting 0 to INVALID_PADDR for the GICC and
> GICV base. At the same time only set the size of each region when the
> base address is not 0.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>

> ---
>  xen/arch/arm/gic-v3.c | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
> index 955591b..bb1861e 100644
> --- a/xen/arch/arm/gic-v3.c
> +++ b/xen/arch/arm/gic-v3.c
> @@ -1356,7 +1356,6 @@ gic_acpi_parse_madt_cpu(struct acpi_subtable_header 
> *header,
>      if ( !cpu_base_assigned )
>      {
>          cbase = processor->base_address;
> -        csize = SZ_8K;
>          vbase = processor->gicv_base_address;
>          gicv3_info.maintenance_irq = processor->vgic_interrupt;
>  
> @@ -1505,6 +1504,25 @@ static void __init gicv3_acpi_init(void)
>          panic("GICv3: No valid GICC entries exists");
>  
>      gicv3.rdist_stride = 0;
> +
> +    /*
> +     * In ACPI, 0 is considered as the invalid address. However the rest
> +     * of the initialization rely on the invalid address to be
> +     * INVALID_ADDR.
> +     *
> +     * Also set the size of the GICC and GICV when there base address
> +     * is not invalid as those values are not present in ACPI.
> +     */
> +    if ( !cbase )
> +        cbase = INVALID_PADDR;
> +    else
> +        csize = SZ_8K;
> +
> +    if ( !vbase )
> +        vbase = INVALID_PADDR;
> +    else
> +        vsize = GUEST_GICC_SIZE;
> +
>  }
>  #else
>  static void __init gicv3_acpi_init(void) { }
> -- 
> 1.9.1
> 

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