Re: [PATCH] xen/arm: report proper GIC version via XEN_DOMCTL_getdomaininfo

[Teddy Astie <teddy.astie@xxxxxxxxxx>]

Le 09/07/2026 à 15:22, Julian Vetter a écrit :
> When creating a domain on ARM, and passing XEN_DOMCTL_CONFIG_GIC_NATIVE
> for the gic_version field in the struct xen_arch_domainconfig,
> arch_sanitise_domain_config() resolves this to the approrpiate GIC_V2 or
> GIC_V3 version the domain actually has, based on the host's
> gic_hw_version(). That value is stored in the domain as
> d->arch.vgic.version, but can't be queried through any other domctl
> later. Toolstacks that create and build a domain in the same call
> already have this info from the createdomain reply and never need to ask
> again.
>
> Toolstacks that create a domain and build it later from a separate
> process do need to ask again. But, the ARM implementation only fills in
> info->flags and info->gpaddr_bits. info->arch_config is left zeroed, so
> XEN_DOMCTL_getdomaininfo always reports gic_version as
> XEN_DOMCTL_CONFIG_GIC_NATIVE (0) regardless of what was actually
> configured earlier.
>
> Signed-off-by: Julian Vetter <julian.vetter@xxxxxxxxxx>
> ---
>   xen/arch/arm/domctl.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/xen/arch/arm/domctl.c b/xen/arch/arm/domctl.c
> index 6c9a3f9920..b76af56fad 100644
> --- a/xen/arch/arm/domctl.c
> +++ b/xen/arch/arm/domctl.c
> @@ -24,6 +24,8 @@ void arch_get_domain_info(const struct domain *d,
>       info->flags |= XEN_DOMINF_hap;
>   
>       info->gpaddr_bits = p2m_ipa_bits;
> +
> +    info->arch_config.gic_version = d->arch.vgic.version;
>   }
>   
>   static int handle_vuart_init(struct domain *d,
That probably wants a Fixes: note given that the current behavior is 
incomplete.
Although, there are a few issues, the hypercall part 
(arch_config.gic_version) uses
#define XEN_DOMCTL_CONFIG_GIC_NATIVE    0
#define XEN_DOMCTL_CONFIG_GIC_V2        1
#define XEN_DOMCTL_CONFIG_GIC_V3        2

while internal ARM code (arch.vgic.version) uses

enum gic_version {
    GIC_INVALID = 0,    /* the default until explicitly set up */
    GIC_V2,
    GIC_V3,
};

That happens to match, but that may want to be adjusted to not break in 
case these 2 representations diverges.
Teddy

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