Re: [PATCH v2 3/4] s390x/pv: Introduce a s390_pv_check() helper for runtime

[Janosch Frank]

On 1/6/23 08:53, Cédric Le Goater wrote:
> From: Cédric Le Goater <clg@redhat.com>
>
> If a secure kernel is started in a non-protected VM, the OS will hang
> during boot without giving a proper error message to the user.

Most of the time you see nothing in the console because libvirt is too 
slow. If you start the VM in paused mode, attach a console and then 
resume it, then you'll see a nice error message.

> Perform the checks on Confidential Guest support at runtime with an
> helper called from the service call switching the guest to protected
> mode.

If we don't have PV support then the subcodes >=8 are a specification 
exception so this is never executed AFAIK.

>       if (env->psw.mask & PSW_MASK_PSTATE) {
>           s390_program_interrupt(env, PGM_PRIVILEGED, ra);
> @@ -176,6 +177,12 @@ out:
>               return;
>           }
>   
> +        if (!s390_pv_check(&local_err)) {
> +            error_report_err(local_err);
> +            env->regs[r1 + 1] = DIAG_308_RC_INVAL_FOR_PV;
> +            return;
> +        }
> +
>           s390_ipl_reset_request(cs, S390_RESET_PV);
>           break;
>       default: