linux-kernel - Re: [PATCH 5/5] arm64: dts: qcom: x1e/x1p: Add EL2 overlay for WoA devices

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <9e5c2e9b6685e7a621cca926530bd271@trvn.ru>
Date: Fri, 02 May 2025 17:55:00 +0500
From: Nikita Travkin <nikita@...n.ru>
To: Marc Zyngier <maz@...nel.org>
Cc: Bjorn Andersson <andersson@...nel.org>, Konrad Dybcio
 <konradybcio@...nel.org>, Rob Herring <robh@...nel.org>, Krzysztof Kozlowski
 <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>,
 cros-qcom-dts-watchers@...omium.org, Jens Glathe
 <jens.glathe@...schoolsolutions.biz>, linux-arm-msm@...r.kernel.org,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/5] arm64: dts: qcom: x1e/x1p: Add EL2 overlay for WoA
 devices

Marc Zyngier писал(а) 02.05.2025 15:38:
> On Thu, 01 May 2025 18:03:45 +0100,
> Nikita Travkin <nikita@...n.ru> wrote:
>> 
>> WoA devices using x1e/x1p use android firmware to boot, which notably
>> includes Gunyah hypervisor. This means that, so far, Linux-based OS
>> could only boot in EL1 on those devices.
>> 
>> However Windows can replace Gunyah upon boot with it's own hypervisor,
>> and with the use of tools such as "slbounce", it's possible to do the
>> same for Linux-based OS, in which case some modifications to the DT are
>> necessary to facilitate the absence of Gunyah services.
>> 
>> Add a EL2-specific DT overlay and apply it to x1e/x1p WoA devices to
>> create -el2.dtb for each of them alongside "normal" dtb.
>> 
>> Signed-off-by: Nikita Travkin <nikita@...n.ru>
>> ---
>>  arch/arm64/boot/dts/qcom/Makefile      | 36 +++++++++++++++++---------
>>  arch/arm64/boot/dts/qcom/x1-el2.dtso   | 46 ++++++++++++++++++++++++++++++++++
>>  arch/arm64/boot/dts/qcom/x1e80100.dtsi |  2 +-
>>  3 files changed, 71 insertions(+), 13 deletions(-)
>>
> 
> [...]
> 
>> diff --git a/arch/arm64/boot/dts/qcom/x1-el2.dtso b/arch/arm64/boot/dts/qcom/x1-el2.dtso
>> new file mode 100644
>> index 0000000000000000000000000000000000000000..7a818045ef098b44632df45253d32e31c5c7aeed
>> --- /dev/null
>> +++ b/arch/arm64/boot/dts/qcom/x1-el2.dtso
>> @@ -0,0 +1,46 @@
>> +// SPDX-License-Identifier: BSD-3-Clause
>> +
>> +/*
>> + * x1 specific modifications required to boot in EL2.
>> + */
>> +
>> +/dts-v1/;
>> +/plugin/;
>> +
>> +/* We can't and don't need to use zap shader in EL2 as linux can zap the gpu on it's own. */
>> +&gpu_zap_shader {
>> +	status = "disabled";
>> +};
>> +
>> +/*
>> + * When running under Gunyah, this IOMMU is controlled by the firmware,
>> + * however when we take ownership of it in EL2, we need to configure
>> + * it properly to use PCIe.
>> + */
>> +&pcie3 {
>> +	iommu-map = <0 &pcie_smmu 0x30000 0x10000>;
>> +};
>> +
>> +&pcie4 {
>> +	iommu-map = <0 &pcie_smmu 0x40000 0x10000>;
>> +};
>> +
>> +&pcie5 {
>> +	iommu-map = <0 &pcie_smmu 0x50000 0x10000>;
>> +};
>> +
>> +&pcie6a {
>> +	iommu-map = <0 &pcie_smmu 0x60000 0x10000>;
>> +};
>> +
>> +&pcie_smmu {
>> +	status = "okay";
>> +};
>> +
>> +/*
>> + * The "SBSA watchdog" is implemented in software in Gunyah
>> + * and can't be used when running in EL2.
>> + */
>> +&sbsa_watchdog {
>> +	status = "disabled";
>> +};
> 
> I also carry this [1] patch to correctly route MSIs from pcie5 to the
> ITS. There is no reason not to. The same treatment could be applied to
> pcie3, but I never tried it.
> 

Oh, interesting... I will add 

    &pcie3 { msi-map = <0 &gic_its 0xb0000 0x10000>; };
    &pcie5 { msi-map = <0 &gic_its 0xd0000 0x10000>; };

to the overlay then. (At least I hope the base value falls in line with
the rule so far, while I know how to confirm iommu-map via acpi tables,
not sure where this one is described, if at all)

Will send a v2 shortly, thanks!

Nikita

> Thanks,
> 
> 	M.
> 
> [1] https://lore.kernel.org/linux-arm-kernel/20241024161814.1827514-1-maz@kernel.org/