Re: [PATCH 07/15] x86/hyperlaunch: initial support for hyperlaunch device tree

[Jason Andryuk <jason.andryuk@xxxxxxx>]

On 2024-11-23 13:20, Daniel P. Smith wrote:
> Add the ability to detect both a formal hyperlaunch device tree or a dom0less
> device tree. If the hyperlaunch device tree is found, then count the number of
> domain entries, reporting if more than one is found.
>
> Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
> ---
>   xen/arch/x86/domain_builder/core.c  | 14 +++++++
>   xen/arch/x86/domain_builder/fdt.c   | 64 ++++++++++++++++++++++++++++-
>   xen/arch/x86/domain_builder/fdt.h   |  5 +++
>   xen/arch/x86/include/asm/bootinfo.h |  1 +
>   4 files changed, 83 insertions(+), 1 deletion(-)
>
> diff --git a/xen/arch/x86/domain_builder/core.c 
> b/xen/arch/x86/domain_builder/core.c
> index 211359895d84..a80f3711c306 100644
> --- a/xen/arch/x86/domain_builder/core.c
> +++ b/xen/arch/x86/domain_builder/core.c
> @@ -40,7 +40,21 @@ void __init builder_init(struct boot_info *bi)
>                      ret);
>               bi->hyperlaunch_enabled = false;
>           }
> +    }
> +
> +    if ( bi->hyperlaunch_enabled )
> +    {
> +        int ret;
> +
> +        printk(XENLOG_INFO "Hyperlauch configuration:\n");
Hyperlaunch

> +        if ( (ret = walk_hyperlaunch_fdt(bi)) < 0 )
> +        {
> +            printk(XENLOG_INFO "  walk of device tree failed (%d)\n", ret);
> +            bi->hyperlaunch_enabled = false;
> +            return;
> +        }
>   
> +        printk(XENLOG_INFO "  Number of domains: %d\n", bi->nr_domains);
>       }
>   }
>   
> diff --git a/xen/arch/x86/domain_builder/fdt.c b/xen/arch/x86/domain_builder/fdt.c
> index 3f9dda8c34c3..ff1ba58b6907 100644
> --- a/xen/arch/x86/domain_builder/fdt.c
> +++ b/xen/arch/x86/domain_builder/fdt.c
> +int __init walk_hyperlaunch_fdt(struct boot_info *bi)
> +{
> +    int ret = 0, hv_node, node;
> +    void *fdt = bootstrap_map_bm(&bi->mods[HYPERLAUNCH_MODULE_IDX]);
> +
> +    if ( unlikely(!fdt) )
> +        return -EINVAL;
> +
> +    hv_node = find_hyperlaunch_node(fdt);
> +    if ( hv_node < 0 )
> +    {
> +        ret = hv_node;
> +        goto err_out;
> +    }
> +
> +    fdt_for_each_subnode(node, fdt, hv_node)
> +    {
> +        ret = fdt_node_check_compatible(fdt, node, "xen,domain");
> +        if ( ret == 0 )
> +            bi->nr_domains++;
> +    }
> +
> +    /* Until multi-domain construction is added, throw an error */
> +    if ( !bi->nr_domains || bi->nr_domains > 1 )
> +        printk(XENLOG_ERR "Hyperlaunch only supports dom0 construction\n");
You continue execution - is that intended?  It'll take the next module 
as the kernel and try to boot?  Would you rather panic?
Regards,
Jason

>   
> + err_out:
>       bootstrap_unmap();
>   
>       return ret;