Re: [PATCH] arm64: dts: qcom: x1: split PAS remoteproc iommus out of x1-el2

[Christopher Obbard <chris.obbard@oss.qualcomm.com>]

Hi Jens,

On Mon, 2026-09-14 at 21:42 +0200, Jens Glathe via B4 Relay wrote:
> From: Jens Glathe <jens.glathe@oldschoolsolutions.biz>
> 
> The shared x1-el2 overlay currently attaches apps_smmu streams to
> remoteproc_adsp/cdsp so Linux can program those SIDs when PAS is
> used to authenticate and reset the DSPs.
> 
> That is wrong for the common WoA EL2 path (slbounce + shipping
> UEFI). There the DSPs are already running from the bootloader and
> the SMMU probe path leaves their SIDs in bypass. Describing iommus
> on the remoteproc nodes replaces that bypass with a translated
> context that is never set up, and boot dies in an SMMU fault storm
> on SID 0x1000 before userspace.
> 
> Move the remoteproc iommus into a new x1-el2-pas overlay and apply
> it only on hamoa-iot-evk, which is the platform that actually needs
> PAS-managed remoteproc under EL2. Other x1e/x1p -el2 DTBs stay on
> the generic overlay.
> 
> Tested on:
>   Lenovo Yoga Slim 7x (83ED, BIOS NHCN62WW) by Birk
>   Lenovo Thinkpad T14s G6 (21N1, Hamoa)
>   Lenovo IdeaCentre Mini 01q8x10 (91B6, Purwa)
>   Lenovo Ideapad 5 2in1 14Q8X9 (83GH, Purwa)
> 
> Fixes: 47c88db49f6c ("arm64: dts: qcom: hamoa: Add remoteproc IOMMUS in EL2 device trees")
> Link: https://lore.kernel.org/all/20260130073113.3091884-1-xin.liu@oss.qualcomm.com/
> Suggested-by: Nikita Travkin <nikita@trvn.ru>
> Assisted-by: Grok(xAI):4.6
> Tested-by: Birk Skyum <birk.skyum@pm.me>
> Signed-off-by: Jens Glathe <jens.glathe@oldschoolsolutions.biz>

Tested-by: Christopher Obbard <chris.obbard@oss.qualcomm.com> # Lenovo 
T14s Hamoa


Thanks!

Chris

> ---
>  arch/arm64/boot/dts/qcom/Makefile        |  2 +-
>  arch/arm64/boot/dts/qcom/x1-el2-pas.dtso | 21 +++++++++++++++++++++
>  arch/arm64/boot/dts/qcom/x1-el2.dtso     |  8 --------
>  3 files changed, 22 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/qcom/Makefile b/arch/arm64/boot/dts/qcom/Makefile
> index d6547fb18edf0..1d1cdf057fd99 100644
> --- a/arch/arm64/boot/dts/qcom/Makefile
> +++ b/arch/arm64/boot/dts/qcom/Makefile
> @@ -22,7 +22,7 @@ dtb-$(CONFIG_ARCH_QCOM)	+= glymur-hp-elitebook-x-g2q.dtb
>  dtb-$(CONFIG_ARCH_QCOM)	+= glymur-lenovo-yoga-slim7x.dtb
>  dtb-$(CONFIG_ARCH_QCOM)	+= hamoa-iot-evk.dtb
>  
> -hamoa-iot-evk-el2-dtbs	:= hamoa-iot-evk.dtb x1-el2.dtbo
> +hamoa-iot-evk-el2-dtbs := hamoa-iot-evk.dtb x1-el2.dtbo x1-el2-pas.dtbo
>  
>  dtb-$(CONFIG_ARCH_QCOM)	+= hamoa-iot-evk-el2.dtb
>  dtb-$(CONFIG_ARCH_QCOM)	+= hamoa-lenovo-ideacentre-mini-01q8x10.dtb
> diff --git a/arch/arm64/boot/dts/qcom/x1-el2-pas.dtso b/arch/arm64/boot/dts/qcom/x1-el2-pas.dtso
> new file mode 100644
> index 0000000000000..05364b439182a
> --- /dev/null
> +++ b/arch/arm64/boot/dts/qcom/x1-el2-pas.dtso
> @@ -0,0 +1,21 @@
> +// SPDX-License-Identifier: BSD-3-Clause
> +/*
> + * Extra EL2 overlay for platforms where Linux programs remoteproc
> + * IOMMU streams because PAS is available.
> + *
> + * Do not apply this on current WoA firmware. Those DSPs are started
> + * by the bootloader and rely on the SMMU SID bypass set up in
> + * qcom_smmu_cfg_probe(). Attaching iommus here replaces that bypass
> + * with an empty translated context and faults SID 0x1000.
> + */
> +
> +/dts-v1/;
> +/plugin/;
> +
> +&remoteproc_adsp {
> +	iommus = <&apps_smmu 0x1000 0x80>;
> +};
> +
> +&remoteproc_cdsp {
> +	iommus = <&apps_smmu 0x0c00 0x0>;
> +};
> diff --git a/arch/arm64/boot/dts/qcom/x1-el2.dtso b/arch/arm64/boot/dts/qcom/x1-el2.dtso
> index ee006742d6f3b..175679be01eba 100644
> --- a/arch/arm64/boot/dts/qcom/x1-el2.dtso
> +++ b/arch/arm64/boot/dts/qcom/x1-el2.dtso
> @@ -52,14 +52,6 @@ &pcie_smmu {
>  	status = "okay";
>  };
>  
> -&remoteproc_adsp {
> -	iommus = <&apps_smmu 0x1000 0x80>;
> -};
> -
> -&remoteproc_cdsp {
> -	iommus = <&apps_smmu 0x0c00 0x0>;
> -};
> -
>  /*
>   * The "SBSA watchdog" is implemented in software in Gunyah
>   * and can't be used when running in EL2.
> 
> ---
> base-commit: 1a1de54f7369cd2b5bac0f265910e60ad3a6b4c3
> change-id: 20260514-x1-el2-unfuck-0c46167538f4
> 
> Best regards,