Re: [PATCH v5 09/12] xen/arm: domain_build/dom0less-build: adjust domains config to support eSPIs

[Julien Grall <julien@xxxxxxx>]

Hi Leonid,

On 29/08/2025 17:06, Leonid Komarianskyi wrote:
> The Dom0 and DomUs logic for the dom0less configuration in create_dom0() and
> arch_create_domUs() has been updated to account for extended SPIs when
> supported by the hardware and enabled with CONFIG_GICV3_ESPI.
Style: We don't commonly use past tense to describe the new behavior.
>   xen/arch/arm/dom0less-build.c   |  2 +-
>   xen/arch/arm/domain_build.c     |  2 +-
>   xen/arch/arm/include/asm/vgic.h | 19 +++++++++++++++++++
>   3 files changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/xen/arch/arm/dom0less-build.c b/xen/arch/arm/dom0less-build.c
> index 69b9ea22ce..02d5559102 100644
> --- a/xen/arch/arm/dom0less-build.c
> +++ b/xen/arch/arm/dom0less-build.c
> @@ -285,7 +285,7 @@ void __init arch_create_domUs(struct dt_device_node *node,
>       {
>           int vpl011_virq = GUEST_VPL011_SPI;
>   
> -        d_cfg->arch.nr_spis = VGIC_DEF_NR_SPIS;
> +        d_cfg->arch.nr_spis = vgic_def_nr_spis();
>   
>           /*
>            * The VPL011 virq is GUEST_VPL011_SPI, unless direct-map is
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index d91a71acfd..39eea0be00 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -2054,7 +2054,7 @@ void __init create_dom0(void)
>   
>       /* The vGIC for DOM0 is exactly emulating the hardware GIC */
>       dom0_cfg.arch.gic_version = XEN_DOMCTL_CONFIG_GIC_NATIVE;
> -    dom0_cfg.arch.nr_spis = VGIC_DEF_NR_SPIS;
> +    dom0_cfg.arch.nr_spis = vgic_def_nr_spis();
>       dom0_cfg.arch.tee_type = tee_get_type();
>       dom0_cfg.max_vcpus = dom0_max_vcpus();
>   
> diff --git a/xen/arch/arm/include/asm/vgic.h b/xen/arch/arm/include/asm/vgic.h
> index 912d5b7694..3aa22114ba 100644
> --- a/xen/arch/arm/include/asm/vgic.h
> +++ b/xen/arch/arm/include/asm/vgic.h
> @@ -347,6 +347,25 @@ extern void vgic_check_inflight_irqs_pending(struct vcpu 
> *v,
>   /* Default number of vGIC SPIs. 32 are substracted to cover local IRQs. */
>   #define VGIC_DEF_NR_SPIS (min(gic_number_lines(), VGIC_MAX_IRQS) - 32)>
> +static inline unsigned int vgic_def_nr_spis(void)
> +{
> +#ifdef CONFIG_GICV3_ESPI
> +    /*
> +     * Check if the hardware supports extended SPIs (even if the appropriate
> +     * config is set). If not, the common SPI range will be used. Otherwise
> +     * return the maximum eSPI INTID, supported by HW GIC, subtracted by 32.
> +     * For Dom0 and started at boot time DomUs we will add back this value
> +     * during VGIC initialization. This ensures consistent handling for Dom0
> +     * and other domains. For the regular SPI range interrupts in this case,
> +     * the maximum value of VGIC_DEF_NR_SPIS will be used.
> +     */
> +    if ( gic_number_espis() > 0 )
> +        return ESPI_BASE_INTID + min(gic_number_espis(), 1024U) - 32;
> +#endif
> +
> +    return VGIC_DEF_NR_SPIS;
This is the only user of VGIC_DEF_NR_SPIS. Therefore, I would prefer if 
we remove the define. This will avoid any confusion between the helper 
and the define.
Cheers,

--
Julien Grall