Re: [PATCH] x86: Conditionalise init_dom0_cpu_policy()

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Thu, Jul 17, 2025 at 07:58:24PM +0200, Alejandro Vallejo wrote:
> Later patches will keep refactoring create_dom0()
> until it can create arbitrary domains. This is one
> small step in that direction.
> 
> Signed-off-by: Alejandro Vallejo <alejandro.garciavallejo@xxxxxxx>
> ---
>  xen/arch/x86/setup.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
> index c6890669b9..6943ffba79 100644
> --- a/xen/arch/x86/setup.c
> +++ b/xen/arch/x86/setup.c
> @@ -1054,7 +1054,8 @@ static struct domain *__init create_dom0(struct 
> boot_info *bi)
>      if ( IS_ERR(d) )
>          panic("Error creating d%u: %ld\n", bd->domid, PTR_ERR(d));
>  
> -    init_dom0_cpuid_policy(d);
> +    if ( pv_shim || d->cdf & (CDF_privileged | CDF_hardware) )

You possibly want this to be:

(d->cdf & (CDF_privileged | CDF_hardware)) == (CDF_privileged | CDF_hardware)

To ensure the contents of dom0_cpuid_cmdline is only applied to dom0,
and not to the hardware or control domains.  I assume it should be
possible to pass a different set of cpuid options for the hardware vs
the control domains.

Thanks, Roger.