[PATCH v2 15/15] efi/arm64: Implement ARM64 DRTM in the stub

Yeoreum Yun yeoreum.yun at arm.com
Tue Oct 20 16:24:40 PDT 2026


One small question...

[..snipped..]

> +void efi_drtm_launch(void)
> +{
> +	if (efi_drtm_policy == EFI_DRTM_OFF)
> +		return;
> +
> +	/*
> +	 * No cache maintenance is required before the launch. v1.4B R42130 in
> +	 * Table 22 "DCE preamble requirements" requires the DRTM_PARAMETERS to
> +	 * be accessible as Normal Write-Back Cacheable, Inner Shareable memory,
> +	 * so the DCE reads them coherently with the writes made above.  R45220
> +	 * in Table 30 "DCE requirements for the DLME" then has the DCE clean
> +	 * and invalidate the whole DLME region to the Point of Coherency before
> +	 * it measures the DLME image, which covers both the Image itself and
> +	 * the handoff struct placed in the DLME region. Thus once we jump into
> +	 * the kernel with MMU and caches off the CPU will see everything the
> +	 * stub wrote.
> +	 */
> +	arm_drtm_dynamic_launch(drtm_cfg.params_addr);

After launching, How to get eventlogs for measurement of DLEM if
tpm_read_log_efi() is used? Doesn't it need to concatenate those
event logs from DRTM eventlog in returned DLEM data?

[...]

-- 
Sincerely,
Yeoreum Yun



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