linux-kernel - Re: [PATCH] powerpc/pseries: detect secure and trusted boot state of the system.

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Date:   Tue, 07 Jul 2020 12:53:56 +1000
From:   Daniel Axtens <dja@...ens.net>
To:     Nayna Jain <nayna@...ux.ibm.com>, linuxppc-dev@...abs.org
Cc:     Michael Ellerman <mpe@...erman.id.au>,
        Mimi Zohar <zohar@...ux.ibm.com>, linux-kernel@...r.kernel.org,
        Nayna Jain <nayna@...ux.ibm.com>
Subject: Re: [PATCH] powerpc/pseries: detect secure and trusted boot state of the system.

As a final extra note,

  https://github.com/daxtens/qemu/tree/pseries-secboot

is a qemu repository that fakes out the relevant properties if anyone
else wants to test this.

Also,

>  3-9 - enabled, OS-defined behaviour. In this patch we map all these
>        values to enabled and enforcing. Again I think this is the
>        appropriate thing to do.

this should read "enabled and enforcing, requirements are at the
discretion of the operating system". Apologies.

Regards,
Daniel

> ibm,trusted-boot isn't published by a current PowerVM LPAR but will be
> published in future. (Currently, trusted boot state is inferred by the
> presence or absense of a vTPM.) It's simply 1 = enabled, 0 = disabled.
>
> As for this patch specifically, with the very small nits below,
>
> Reviewed-by: Daniel Axtens <dja@...ens.net>
>
>> -	node = get_ppc_fw_sb_node();
>> -	enabled = of_property_read_bool(node, "os-secureboot-enforcing");
>> +	if (machine_is(powernv)) {
>> +		node = get_ppc_fw_sb_node();
>> +		enabled =
>> +		    of_property_read_bool(node, "os-secureboot-enforcing");
>> +		of_node_put(node);
>> +	}
>>  
>> -	of_node_put(node);
>> +	if (machine_is(pseries)) {
> Maybe this should be an else if?
>
>> +		secureboot = of_get_property(of_root, "ibm,secure-boot", NULL);
>> +		if (secureboot)
>> +			enabled = (*secureboot > 1) ? true : false;
>> +	}
>>  
>>  	pr_info("Secure boot mode %s\n", enabled ? "enabled" : "disabled");
>>  
>> @@ -38,11 +48,20 @@ bool is_ppc_trustedboot_enabled(void)
>>  {
>>  	struct device_node *node;
>>  	bool enabled = false;
>> +	const u32 *trustedboot;
>>  
>> -	node = get_ppc_fw_sb_node();
>> -	enabled = of_property_read_bool(node, "trusted-enabled");
>> +	if (machine_is(powernv)) {
>> +		node = get_ppc_fw_sb_node();
>> +		enabled = of_property_read_bool(node, "trusted-enabled");
>> +		of_node_put(node);
>> +	}
>>  
>> -	of_node_put(node);
>> +	if (machine_is(pseries)) {
> Likewise.
>> +		trustedboot =
>> +		    of_get_property(of_root, "ibm,trusted-boot", NULL);
>> +		if (trustedboot)
>> +			enabled = (*trustedboot > 0) ? true : false;
>
> Regards,
> Daniel