RE: [PATCH v1 2/8] firmware: arm_rmm: Add VSMMU commands and fields

[Shameer Kolothum Thodi]

> -----Original Message-----
> From: Nicolin Chen <nicolinc@xxxxxxxxxx>
> Sent: 10 September 2026 04:33
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> Subject: [PATCH v1 2/8] firmware: arm_rmm: Add VSMMU commands and
> fields
> 
> DEN0137 2.0-bet3 adds the RSI_VSMMU_GET_INFO command and replaces
> the old
> RSI_VSMMU_ACTIVATE command with RSI_ARCH_DEV_ACTIVATE.
> 
> Add the command IDs, return codes, SMMUv3 device type, and helpers for
> both
> commands.
> 
> Assisted-by: Codex:gpt-5.6-sol
> Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
> ---
>  include/linux/arm-rsi-cmds.h  | 22 ++++++++++++++++++++++
>  include/linux/arm-smccc-rsi.h | 20 ++++++++++++++++++++
>  2 files changed, 42 insertions(+)
> 
> diff --git a/include/linux/arm-rsi-cmds.h b/include/linux/arm-rsi-cmds.h
> index 13478e14c4296..548ab0bcac722 100644
> --- a/include/linux/arm-rsi-cmds.h
> +++ b/include/linux/arm-rsi-cmds.h
> @@ -237,4 +237,26 @@ static inline unsigned long
> rsi_attestation_token_continue(phys_addr_t granule,
>  	return res.a0;
>  }
> 
> +static inline unsigned long rsi_vsmmu_get_info(phys_addr_t addr,
> +					       phys_addr_t *top)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RSI_VSMMU_GET_INFO, addr, &res);
> +	if (res.a0 == RSI_SUCCESS && top)
> +		*top = res.a1;
> +
> +	return res.a0;
> +}
> +
> +static inline unsigned long rsi_arch_dev_activate(phys_addr_t base,
> +						  unsigned long dev_type)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RSI_ARCH_DEV_ACTIVATE, base,
> dev_type, &res);

These calls leave unused input registers unspecified, whereas
DEN0137 bet3 B1.2 marks them SBZ. Could we explicitly zero them?

"On calling an RMI or RSI command, any of X1- X16 which are not
 specified as input values in the command definition SBZ"

Thanks,
Shameer