Re: [PATCH 01/17] tpm: Define a kernel-owned TPM NV index that can't be modified by userland

[Jarkko Sakkinen <jarkko@kernel.org>]

On Thu, Oct 08, 2026 at 06:20:17AM -0700, Matthew Garrett wrote:
> +#ifdef CONFIG_TCG_TPM_KERNEL_NVINDEX
> +/*
> + * Commands that undefine or modify an NV index, and the position of the
> + * NV index in the command's handle area.
> + */
> +static const struct {
> +	u32 cc;
> +	unsigned int handle;
> +} tpm2_nv_modify_cmds[] = {
> +	{ TPM2_CC_NV_UNDEFINE_SPACE_SPECIAL,	0 },
> +	{ TPM2_CC_NV_UNDEFINE_SPACE,		1 },
> +	{ TPM2_CC_NV_INCREMENT,			1 },
> +	{ TPM2_CC_NV_SET_BITS,			1 },
> +	{ TPM2_CC_NV_EXTEND,			1 },
> +	{ TPM2_CC_NV_WRITE,			1 },
> +	{ TPM2_CC_NV_WRITE_LOCK,		1 },
> +	{ TPM2_CC_NV_CHANGE_AUTH,		0 },
> +	{ TPM2_CC_NV_READ_LOCK,			1 },
> +};

There's also tpm2_ordinal_duration_map:

	static const struct {
		unsigned long ordinal;
		unsigned long duration;
	} tpm2_ordinal_duration_map[] = {
		{TPM2_CC_STARTUP, 750},
		{TPM2_CC_SELF_TEST, 3000},
		{TPM2_CC_GET_RANDOM, 2000},
		{TPM2_CC_SEQUENCE_UPDATE, 750},
		{TPM2_CC_SEQUENCE_COMPLETE, 750},
		{TPM2_CC_EVENT_SEQUENCE_COMPLETE, 750},
		{TPM2_CC_HASH_SEQUENCE_START, 750},
		{TPM2_CC_VERIFY_SIGNATURE, 30000},
		{TPM2_CC_PCR_EXTEND, 750},
		{TPM2_CC_HIERARCHY_CONTROL, 2000},
		{TPM2_CC_HIERARCHY_CHANGE_AUTH, 2000},
		{TPM2_CC_GET_CAPABILITY, 750},
		{TPM2_CC_NV_READ, 2000},
		{TPM2_CC_CREATE_PRIMARY, 300000},
		{TPM2_CC_CREATE, 300000},
		{TPM2_CC_CREATE_LOADED, 300000},
	};

I'd consider something along the lines of:

	enum tpm2_cc_nv {
		TPM2_CC_NV_NA = -1,	/* not available */
		TPM2_CC_NV_H0 = 0,
		TPM2_CC_NV_H1 = 1,
	};

	static const struct {
		u32 cc;
		u32 duration;
		enum tpm2_cc_nv nv;
	} tpm2_cc_map[] {
		/* ... */
	};

Br, Jarkko