Re: [PATCH v9 07/18] x86/virt/tdx: Do TDX module per-cpu initialization

[Dave Hansen]

On 2/13/23 03:59, Kai Huang wrote:
> @@ -247,8 +395,17 @@ int tdx_enable(void)
>  		ret = __tdx_enable();
>  		break;
>  	case TDX_MODULE_INITIALIZED:
> -		/* Already initialized, great, tell the caller. */
> -		ret = 0;
> +		/*
> +		 * The previous call of __tdx_enable() may only have
> +		 * initialized part of present cpus during module
> +		 * initialization, and new cpus may have become online
> +		 * since then.
> +		 *
> +		 * To make sure all online cpus are TDX-runnable, always
> +		 * do per-cpu initialization for all online cpus here
> +		 * even the module has been initialized.
> +		 */
> +		ret = __tdx_enable_online_cpus();

I'm missing something here.  CPUs get initialized through either:

 1. __tdx_enable(), for the CPUs around at the time
 2. tdx_cpu_online(), for hotplugged CPUs after __tdx_enable()

But, this is a third class.  CPUs that came online after #1, but which
got missed by #2.  How can that happen?