Re: [Xen-devel] [PATCH v3 5/6] xen/arm: introduce nr_spis

[Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>]

Stefano,

Stefano Stabellini writes:

> We don't have a clear way to know how many virtual SPIs we need for the
> boot domains. Introduce a new option under xen,domain to specify the
> number of SPIs to allocate for the domain.
>
> The property is optional, when absent, we'll use the physical number of
> gic lines for dom0less domains, just like for dom0. Given that dom0less
> VMs are meant for static partitioning scenarios where the number of VMs
> is very low, increased memory overhead should not be a problem, and it
> is possible to minimizing it by using "nr_spis".
>
> Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx>
Reviewed-by: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>

> ---
> Changes in v3:
> - improve commit message
> - introduce nr_spis
> ---
>  xen/arch/arm/domain_build.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index 0057a509d1..fc4e5bc4ca 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -2270,7 +2270,6 @@ void __init create_domUs(void)
>          struct domain *d;
>          struct xen_domctl_createdomain d_cfg = {
>              .arch.gic_version = XEN_DOMCTL_CONFIG_GIC_NATIVE,
> -            .arch.nr_spis = 0,
>              .flags = XEN_DOMCTL_CDF_hvm_guest | XEN_DOMCTL_CDF_hap,
>              .max_evtchn_port = -1,
>              .max_grant_frames = 64,
> @@ -2280,13 +2279,13 @@ void __init create_domUs(void)
>          if ( !dt_device_is_compatible(node, "xen,domain") )
>              continue;
>  
> -        if ( dt_property_read_bool(node, "vpl011") )
> -            d_cfg.arch.nr_spis = GUEST_VPL011_SPI - 32 + 1;
> -
>          if ( !dt_property_read_u32(node, "cpus", &d_cfg.max_vcpus) )
>              panic("Missing property 'cpus' for domain %s\n",
>                    dt_node_name(node));
>  
> +        if ( !dt_property_read_u32(node, "nr_spis", &d_cfg.arch.nr_spis) )
> +            d_cfg.arch.nr_spis = gic_number_lines() - 32;
> +
>          d = domain_create(++max_init_domid, &d_cfg, false);
>          if ( IS_ERR(d) )
>              panic("Error creating domain %s\n", dt_node_name(node));


-- 
Volodymyr Babchuk at EPAM
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