On Fri, Sep 06, 2024 at 08:07:12PM GMT, Bartosz Golaszewski wrote:
> From: Gaurav Kashyap <quic_gaurkash@xxxxxxxxxxx>
>
> Qualcomm's ICE (Inline Crypto Engine) contains a proprietary key
> management hardware called Hardware Key Manager (HWKM). Add HWKM support
> to the ICE driver if it is available on the platform. HWKM primarily
> provides hardware wrapped key support where the ICE (storage) keys are
> not available in software and instead protected in hardware.
>
> When HWKM software support is not fully available (from Trustzone), there
> can be a scenario where the ICE hardware supports HWKM, but it cannot be
> used for wrapped keys. In this case, raw keys have to be used without
> using the HWKM. We query the TZ at run-time to find out whether wrapped
> keys support is available.
>
> Tested-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
> Signed-off-by: Gaurav Kashyap <quic_gaurkash@xxxxxxxxxxx>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
> ---
> drivers/soc/qcom/ice.c | 152 +++++++++++++++++++++++++++++++++++++++++++++++--
> include/soc/qcom/ice.h | 1 +
> 2 files changed, 149 insertions(+), 4 deletions(-)
>
> int qcom_ice_enable(struct qcom_ice *ice)
> {
> + int err;
> +
> qcom_ice_low_power_mode_enable(ice);
> qcom_ice_optimization_enable(ice);
>
> - return qcom_ice_wait_bist_status(ice);
> + if (ice->use_hwkm)
> + qcom_ice_enable_standard_mode(ice);
> +
> + err = qcom_ice_wait_bist_status(ice);
> + if (err)
> + return err;
> +
> + if (ice->use_hwkm)
> + qcom_ice_hwkm_init(ice);
> +
> + return err;
> }
> EXPORT_SYMBOL_GPL(qcom_ice_enable);
>
> @@ -150,6 +282,10 @@ int qcom_ice_resume(struct qcom_ice *ice)
> return err;
> }
>
> + if (ice->use_hwkm) {
> + qcom_ice_enable_standard_mode(ice);
> + qcom_ice_hwkm_init(ice);
> + }
> return qcom_ice_wait_bist_status(ice);
> }
> EXPORT_SYMBOL_GPL(qcom_ice_resume);
> @@ -157,6 +293,7 @@ EXPORT_SYMBOL_GPL(qcom_ice_resume);
> int qcom_ice_suspend(struct qcom_ice *ice)
> {
> clk_disable_unprepare(ice->core_clk);
> + ice->hwkm_init_complete = false;
>
> return 0;
> }
> @@ -206,6 +343,12 @@ int qcom_ice_evict_key(struct qcom_ice *ice, int slot)
> }
> EXPORT_SYMBOL_GPL(qcom_ice_evict_key);
>
> +bool qcom_ice_hwkm_supported(struct qcom_ice *ice)
> +{
> + return ice->use_hwkm;
> +}
> +EXPORT_SYMBOL_GPL(qcom_ice_hwkm_supported);
> +
> static struct qcom_ice *qcom_ice_create(struct device *dev,
> void __iomem *base)
> {
> @@ -240,6 +383,7 @@ static struct qcom_ice *qcom_ice_create(struct device *dev,
> engine->core_clk = devm_clk_get_enabled(dev, NULL);
> if (IS_ERR(engine->core_clk))
> return ERR_CAST(engine->core_clk);
> + engine->use_hwkm = qcom_scm_has_wrapped_key_support();
This still makes the decision on whether to use HW-wrapped keys on
behalf of a user. I suppose this is incorrect. The user must be able to
use raw keys even if HW-wrapped keys are available on the platform. One
of the examples for such use-cases is if a user prefers to be able to
recover stored information in case of a device failure (such recovery
will be impossible if SoC is damaged and HW-wrapped keys are used).
>
> if (!qcom_ice_check_supported(engine))
> return ERR_PTR(-EOPNOTSUPP);
> diff --git a/include/soc/qcom/ice.h b/include/soc/qcom/ice.h
> index 9dd835dba2a7..1f52e82e3e1c 100644
> --- a/include/soc/qcom/ice.h
> +++ b/include/soc/qcom/ice.h
> @@ -34,5 +34,6 @@ int qcom_ice_program_key(struct qcom_ice *ice,
> const struct blk_crypto_key *bkey,
> u8 data_unit_size, int slot);
> int qcom_ice_evict_key(struct qcom_ice *ice, int slot);
> +bool qcom_ice_hwkm_supported(struct qcom_ice *ice);
> struct qcom_ice *of_qcom_ice_get(struct device *dev);
> #endif /* __QCOM_ICE_H__ */
>
> --
> 2.43.0
>
--
With best wishes
Dmitry
