linux-kernel - Re: [PATCH v4 12/12] arm64: dts: qcom: Add EL2 overlay for Lemans

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

Message-ID: <20251008115621.xogashum3s4auqah@hu-mojha-hyd.qualcomm.com>
Date: Wed, 8 Oct 2025 17:26:21 +0530
From: Mukesh Ojha <mukesh.ojha@....qualcomm.com>
To: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
Cc: Manivannan Sadhasivam <mani@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>, linux-arm-msm@...r.kernel.org,
        linux-remoteproc@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 12/12] arm64: dts: qcom: Add EL2 overlay for Lemans

On Wed, Oct 08, 2025 at 12:13:03PM +0200, Konrad Dybcio wrote:
> On 10/8/25 9:32 AM, Mukesh Ojha wrote:
> > On Tue, Oct 07, 2025 at 02:55:04PM -0700, Manivannan Sadhasivam wrote:
> >> On Tue, Oct 07, 2025 at 10:18:57PM +0530, Mukesh Ojha wrote:
> >>> All the Lemans IOT variants boards are using Gunyah hypervisor which
> >>> means that, so far, Linux-based OS could only boot in EL1 on those
> >>> devices.  However, it is possible for us to boot Linux at EL2 on these
> >>> devices [1].
> >>>
> >>> When running under Gunyah, remote processor firmware IOMMU streams is
> >>> controlled by the Gunyah however when Linux take ownership of it in EL2,
> >>> It need to configure it properly to use remote processor.
> >>>
> >>> Add a EL2-specific DT overlay and apply it to Lemans IOT variant
> >>> devices to create -el2.dtb for each of them alongside "normal" dtb.
> >>>
> >>> [1]
> >>> https://docs.qualcomm.com/bundle/publicresource/topics/80-70020-4/boot-developer-touchpoints.html#uefi
> >>>
> >>> Signed-off-by: Mukesh Ojha <mukesh.ojha@....qualcomm.com>
> >>> ---
> 
> [...]
> 
> >>> +&iris {
> >>> +	/* TODO: Add video-firmware iommus to start IRIS from EL2 */
> >>
> >> So the missing 'iommus' property is the only blocker to enable IRIS?
> > 
> > Yes, but this would require some changes in the driver as well to create
> > a platform device for the firmware and IOMMU domain, and to attach the
> > firmware device to the domain.
> 
> "yes, but actually no"
> 
> > 
> > There was some discussion around this in v2[1], where I added support
> > for video. However, the change involved hooking into the video-firmware
> > property, which was used for Venus.  There were concerns[2] about following
> > the same approach for Iris, and due to that, we have dropped video
> > support for now.  However, an RFC has been posted from our side to
> > handle such scenarios[3], as of now unclear about the direction for
> > Iris.
> > 
> > 
> > [1] https://lore.kernel.org/lkml/aKooCFoV3ZYwOMRx@linaro.org/
> > 
> > [2] https://lore.kernel.org/lkml/20250627-video_cb-v3-0-51e18c0ffbce@quicinc.com/
> > 
> > [3] https://lore.kernel.org/all/20250928171718.436440-1-charan.kalla@oss.qualcomm.com/
> > 
> > [4] https://lore.kernel.org/lkml/4a32bbec-2baf-4210-a7c1-1ddcd45d30c8@oss.qualcomm.com/
> 
> Reword the comment to "/* More driver work is needed */" since there
> is nothing more you can do at the moment and you most likely don't
> want to block your series on resolving the above entanglement

Sure.

> 
> Konrad

-- 
-Mukesh Ojha