Re: [PATCH 08/12] xen/arm: if is_domain_direct_mapped use native addresses for GICv2

[Julien Grall <julien@xen.org>]

On 15/04/2020 02:02, Stefano Stabellini wrote:
> Today we use native addresses to map the GICv2 for Dom0 and fixed
> addresses for DomUs.
> 
> This patch changes the behavior so that native addresses are used for
> any domain that is_domain_direct_mapped.
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
> ---
>   xen/arch/arm/domain_build.c | 10 +++++++---
>   xen/arch/arm/vgic-v2.c      | 12 ++++++------
>   xen/arch/arm/vgic/vgic-v2.c |  2 +-
>   xen/include/asm-arm/vgic.h  |  1 +
>   4 files changed, 15 insertions(+), 10 deletions(-)
> 
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index 627e0c5e8e..303bee60f6 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -1643,8 +1643,12 @@ static int __init make_gicv2_domU_node(struct kernel_info *kinfo)
>       int res = 0;
>       __be32 reg[(GUEST_ROOT_ADDRESS_CELLS + GUEST_ROOT_SIZE_CELLS) * 2];
>       __be32 *cells;
> +    struct domain *d = kinfo->d;
> +    char buf[38];
>   
> -    res = fdt_begin_node(fdt, "interrupt-controller@"__stringify(GUEST_GICD_BASE));
> +    snprintf(buf, sizeof(buf), "interrupt-controller@%"PRIx64,
> +             d->arch.vgic.dbase);
> +    res = fdt_begin_node(fdt, buf);
>       if ( res )
>           return res;
>   
> @@ -1666,9 +1670,9 @@ static int __init make_gicv2_domU_node(struct kernel_info *kinfo)
>   
>       cells = &reg[0];
>       dt_child_set_range(&cells, GUEST_ROOT_ADDRESS_CELLS, GUEST_ROOT_SIZE_CELLS,
> -                       GUEST_GICD_BASE, GUEST_GICD_SIZE);
> +                       d->arch.vgic.dbase, GUEST_GICD_SIZE);
>       dt_child_set_range(&cells, GUEST_ROOT_ADDRESS_CELLS, GUEST_ROOT_SIZE_CELLS,
> -                       GUEST_GICC_BASE, GUEST_GICC_SIZE);
> +                       d->arch.vgic.cbase, GUEST_GICC_SIZE);

You can't use the native base address and not the native size. 
Particularly, this is going to screw any GIC using 8KB alias.

It would be preferable if only expose part of the CPU interface as we do 
for the guest. So d->arch.vgic.cbase would be equal to vgic_v2_hw.dbase 
+ vgic_v2.hw.aliased_offset.


Cheers,

-- 
Julien Grall