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Tue, 08 Sep 2026 02:27:54 -0700 (PDT) X-Received: by 2002:a17:90b:1b44:b0:398:ba96:1afd with SMTP id 98e67ed59e1d1-39b2613249fmr38111536a91.8.1788859674092; Tue, 08 Sep 2026 02:27:54 -0700 (PDT) Received: from [10.218.26.96] ([202.46.22.19]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-1433171a97esm35306844c88.12.2026.09.08.02.27.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 08 Sep 2026 02:27:53 -0700 (PDT) Message-ID: <53f00c7e-8ad4-47c4-910e-a78e0c8a9626@oss.qualcomm.com> Date: Tue, 8 Sep 2026 14:57:47 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 0/6] Add TEE based client driver for UEFI Secure Application From: Harshal Dev To: Dmitry Baryshkov Cc: Jens Wiklander , Sumit Garg , Amirreza Zarrabi , Bjorn Andersson , Konrad Dybcio , Basant Kumar , Apurupa Pattapu , Arun Kumar Neelakantam , op-tee@lists.trustedfirmware.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org References: <20260722-qcom_uefisecapp_migrate_qcomtee-v2-0-b8a8fcbe4211@oss.qualcomm.com> <10a091a4-89a5-4a0c-820d-c5b91dd52529@oss.qualcomm.com> Content-Language: en-US Organization: Qualcomm In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Authority-Analysis: v=2.4 cv=CMEamxrD c=1 sm=1 tr=0 ts=6a9fd51c cx=c_pps a=vVfyC5vLCtgYJKYeQD43oA==:117 a=fChuTYTh2wq5r3m49p7fHw==:17 a=IkcTkHD0fZMA:10 a=VdqzKS8jKosA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=_glEPmIy2e8OvE2BGh3C:22 a=P-IC7800AAAA:8 a=NEAV23lmAAAA:8 a=VwQbUJbxAAAA:8 a=EUspDBNiAAAA:8 a=65V9a3KYukFMpB2mifMA:9 a=QEXdDO2ut3YA:10 a=rl5im9kqc5Lf4LNbBjHf:22 a=d3PnA9EDa4IxuAV0gXij:22 X-Proofpoint-Spam-Info: AW1haW4tMjYwOTA4MDA5OSBTYWx0ZWRfX0ZFT/ape+yHV CO3Se5faXFLHXtAwZwav9mn2z+CkYPZCpq9OLamwMl78G6AQkfQm8ni1Hm5pUiW948VvSXgyNoO kyYR4picg7AxQgu1/v53L0bwfClRasQ= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTA4MDA5OSBTYWx0ZWRfX9+i4tLQsc3VX KH8TU87nlUhSYyZwxNix5hjzSWalr/TV/QkgRbEpsh+G2mHcB+TSB9XBkVVo6Zn7ezpMQY0hB4l nQEfKtgX3LSqIa16dRzaHclpN4kqR+YTf+vPKJvcVAI3PFPYd0wNdj3ak5CXDyYih4tZ55UFL8o LxVXCbHypTpFp1XjIiuySnM6M+ISlEdMciJC3VCS43Pxegi7kZFHo8QK6hhjiDLu56+ceYX1Xey Uh4TXAf/GoODGVwtpauTeRVaTXAH2On9xfCGHGhD3vAW6geLM5gXLN9EfwGMcwtoGTQE5wuLfSY wsT5X44iFX//hjiZPE4waXuZ0YhHVTIH7R6LXVlhpUhSqaJ/Fvf2VJmzopMyzGwaMz8x9qNFoCE o3Ry00kyU+1ErHS5hNOpYbTSYtP3qGtZWKUPl3O9R+wRPcEDZ+JM1qM+aoUkV68z1AOf829ycBd AiKsW/YV379IP5lSWGA== X-Proofpoint-ORIG-GUID: vDXT-bAFRZpMSoACWeFyrkn0-n3DGiH2 X-Proofpoint-GUID: vDXT-bAFRZpMSoACWeFyrkn0-n3DGiH2 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-08_01,2026-09-07_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 phishscore=0 clxscore=1015 priorityscore=1501 bulkscore=0 spamscore=0 suspectscore=0 adultscore=0 malwarescore=0 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2609080099 Hi Dmitry, Gentle reminder. I am hoping we are aligned now. Overall QSEECOM can be a separate effort for supporting older devices without SMCInvoke/QCOMTEE support. By moving forward with this series and with a separate one for QSEECOM, we will be able to support EFI variables on all Qualcomm platforms supported upstream. Regards, Harshal On 02-09-2026 01:41 pm, Harshal Dev wrote: > Hi Dmitry, > > On 29-08-2026 08:19 pm, Dmitry Baryshkov wrote: >> On Wed, Aug 12, 2026 at 05:00:27PM +0530, Harshal Dev via OP-TEE wrote: >>> Hi Dmitry, >> >> Hi Harshal, please excuse the huge delay from my side, I was on vacation >> and then burried under the rest of the issues. >> > > Ahh I was not aware, I hope you had a good vacation Dmitry. >>> >>> On 10-08-2026 12:37 pm, Dmitry Baryshkov wrote: >>>> On Fri, Jul 24, 2026 at 02:43:42PM +0530, Harshal Dev wrote: >>>>> Hi Dmitry, >>>>> >>>>> On 22-07-2026 01:56 pm, Dmitry Baryshkov wrote: >>>>>> On Wed, Jul 22, 2026 at 12:29:11PM +0530, Harshal Dev wrote: >>>>>>> On Qualcomm SoC based platforms, UEFI stores EFI variables within the >>>>>>> Replay Protected Memory Block (RPMB) which is only accessible by the >>>>>>> Qualcomm Trusted Execution Environment (QTEE). >>>>>> >>>>>> Is it so? I think RPMB is accessible to Linux... >>>>> >>>>> I should have been more descriptive here, RPMB is accessible by Linux but >>>>> its frames can only be prepared by QTEE. >>>>> >>>>> The RPMB key which is one-time programmed into the storage controller to allow >>>>> authentication of the RPMB frames is generated by and only available to a TEE. >>>>> So on Qualcomm platforms (and many others platforms with a TEE) Linux can only >>>>> route the RPMB frames generated by QTEE to the storage, it cannot create and >>>>> write the RPMB frames itself (it doesn't have access to the key). >>>>> >>>>> While it is possible for Linux to generate/program/store this key, on Qualcomm >>>>> platforms we do not want Linux to do so because we do not trust it. We trust >>>>> QTEE. >>>>> >>>>> I will re-phrase this and make it a bit more clear everywhere. >>>> >>>> OK. >>>> >>>>> >>>>>> >>>>>>> For Qualcomm platforms without emulated RPMB support, specifically >>>>>> >>>>>> What is emulated RPMB support? Why is it mentioned here? Which platforms >>>>>> use emulated RPMB? >>>>> >>>>> Emulated RPMB refers to RPMB on a storage which doesn't have its own firmware. >>>>> Primarily, NAND/NOR storage. Unlike UFS/eMMC storage, NAND/NOR storage does not >>>>> have a storage controller where we can program the RPMB key to be used by the >>>>> firmware. So we must 'emulate' RPMB by moving the storage driver within QTEE >>>>> and making the driver hold/use the key. >>>>> >>>>> Qualcomm compute SoCs (Glymur, Hamoa) have RPMB available on SPI-*NOR* storage, >>>>> and a driver for communicating with it is also available in QTEE. And so, these >>>>> have 'emulated' RPMB. >>>> >>>> This needs to be explained in the cover letter. >>>> >>> >>> Ack. >>>>> >>>>> I will add this detail in an updated cover letter. >>>>>> >>>>>>> platforms where RPMB is not located within SPI-NOR storage and instead >>>>>>> located on UFS/EMMC storage, non-volatile EFI variables can only be set via >>>>>>> a callback request from the UEFI Secure Application to the RPMB service >>>>>>> running in user-space (within the QTEE supplicant [1]). >>>>>> >>>>>> Can it be moved to the kernel? >>>>> >>>>> We have a plan to move the RPMB service to the kernel similar to OPTEE: >>>>> https://elixir.bootlin.com/linux/v7.2-rc3/source/drivers/tee/optee/rpc.c#L449 >>>>> >>>>> It is a work in progress. Once this happens, we don't need QTEE supplicant available >>>>> on the Linux distribution. >>>> >>>> Ok. >>>> >>>>> >>>>>> >>>>>>> >>>>>>> Unlike the QCOM-TEE driver, the QSEECOM driver (used by the current >>>>>>> QSEECOM based uefisecapp) does not support callback requests. >>>>>> >>>>>> How did it work then? I think Windows has been perfectly using QSEECOM >>>>>> rather than QTEE. >>>>> >>>>> It works because Windows on Arm on Qualcomm has SPI-NOR storage. A driver for which >>>> >>>> I have WoA devices without SPI NOR. Windows still can store UEFI >>>> variables. >>>> >>> >>> Ahh, the key point here is 'Windows'. Windows has a separate way of providing >>> RPMB access via a service in the TrEE driver within the OS: >>> https://github.com/microsoft/Windows-driver-samples/tree/main/TrEE >>> >>> However, the Linux QSEECOM driver we have here in upstream does not have that support. >>> And so without the QCOMTEE + QTEE supplicant combination, we cannot access EFI >>> variables on these Qualcomm WoA platforms when they boot with upstream Linux. >> >> So, this must be fixed, I assume? What is the ETA? >> > > I agree, it will have to be a separate effort. If new firmware QTEE releases are not > being rolled out for these existing WoA devices, and if their RPMB exists on UFS/eMMC > then the only way to support EFI variable is to: > 1. Add support for callback requests in the upstream QSEECOM driver. > 2. Add support for RPMB listener in kernel which routes the RPMB frames from QTEE to > the RPMB device via the QSEECOM driver. > > This is significant effort for supporting a protocol which is deprecated on the QTEE > side moving forward. That being said, I do not discourage this effort. We can think of > a plan if we really want to support these devices. I will be happy to engage. > >>> >>>>> is available within QTEE, and so QTEE does not need to make a callback request >>>>> to Linux to request RPMB frame routing. However, in case of UFS/eMMC storage the >>>>> driver only exists in the Linux kernel and so QTEE must make a callback request. >>>>> >>>>> And so, if you try to use the QSEECOM driver to write EFI-variables to RPMB >>>>> on a device with UFS/eMMC storage, it won't work. >>>> >>>> Yep. It seems to work under Windows though. >>>> >>> >>> As explained above, the mechanism is different for Windows. A different driver >>> and a different protocol. :) >> >> Let me be very explicit here. The path used by Windows is tested and >> verified to work on a plethora of the devices. Those devices must work >> with Linux too, so, in my opinion, we should use the same firmware path > > Agreed, as mentioned above, we can think of a plan to support these devices by extending > the QSEECOM driver. > >> and the same firmware interfaces as used by Windows. >> > > The interfaces used on Windows by the TrEE driver are different as per the information > I obtained from Windows team. But we don't need to worry about that, we already have > QSEECOM in upstream which we can extend. > >>>>>>> And on >>>>>>> certain Qualcomm platforms such as the RB3Gen2, attempts to access the >>>>>>> QSEECOM interface fail due to lack of support within Qualcomm TEE. >>>>>> >>>>>> So, I assume, on RB3 Gen2 the QSEECOM doesn't report uefisecapp as >>>>>> supported. Does it? >>>>> >>>>> It doesn't, this API returns -2 if I add RB3 Gen2 in the allow-list for QSEECOM: >>>>> https://elixir.bootlin.com/linux/v7.2-rc3/source/drivers/firmware/qcom/qcom_qseecom.c#L46 >>>> >>>> Does it support QTEE-based uefi variable storage? >>>> >>> >>> It does, the QTEE-based uefi variable storage app, i.e. uefisecapp is loaded by >>> UEFI on RB3Gen2, however, the QSEECOM interface on RB3Gen2 is broken so it misreports >>> it as 'not supported'. But the app is loaded and available, which is why if you apply >>> this patch series, you can communicate with it. Just make sure you take the QTEE >>> release mentioned in this cover letter. >> >> Can't we fix the QSEECOM instead, if one needs to flash another release >> anyways? >> > > QSEECOM is deprecated, requesting support for fixing it is an overhead at this point. > Even if we take the time to fix it ourselves, it won't help, because the QSEECOM driver > doesn't support callback requests and a path to the RPMB device within the Linux kernel. > >>>>>>> On these platforms, a TEE based uefisecapp client driver is required to: >>>>>>> 1. Access cached & volatile EFI variables stored in uefisecapp's memory. >>>>>>> 2. Ensure persistence of non-volatile EFI variables via writes through >>>>>>> the RPMB service hosted in the QTEE supplicant. >>>>>>> >>>>>>> This series introduces such a uefisecapp TEE client driver for the >>>>>>> aforementioned Qualcomm platforms which installs efi-var operations _if_ >>>>>>> the QCOMTEE driver registers support for an object-IPC based uefisecapp >>>>>>> service on the TEE bus during its probe. Only new QTEE firmware versions >>>>>>> available at [2] provide this support. >>>>>> >>>>>> What about existing WoA devices? >>>>> >>>>> New Windows on Arm devices like Hamoa/Glymur work perfectly fine with existing >>>>> QSEECOM based uefisecapp. But they will also work with this new QCOMTEE based >>>>> uefisecapp once they upgrade their firmware. >>>> >>>> Do extisting commercial devices suppot it? For example, does Lenovo T14s >>>> support it? Will it continue to work with this patchset in place? >>> >>> Existing devices like the Lenovo T14s do not have mature QCOMTEE/SMCInvoke support >>> on QTEE side and new QTEE versions for it are not being rolled out. However, this >>> QCOMTEE based uefisecapp driver and the QSEECOM based uefisecapp driver can co-exist. >>> It will not cause any breakage of existing working functionality since the QSEECOM >>> path can probe and continue as usual. >> >> My understanding was that QTEE path completely disables the QSEECOM >> path, does it not? >> > > By 'QTEE path', I believe you mean the 'QCOMTEE/SMCInvoke' protocol path. > > No, both SMCInvoke/QCOMTEE and QSEECOM paths can be supported simultaneously within QTEE. > QTEE does not disable the QSEECOM path when it enables the SMCInvoke/QCOMTEE one. > > You can have both QSEECOM and SMCInvoke clients running together on a Qualcomm platform. > QTEE doesn't impose any restrictions. The control/data paths within QTEE for these > two protocols are completely isolated from each other. > >>> >>> As per your comments on patch 6 of this series, I plan to enable the QCOMTEE based >>> uefisecapp as default 'm'. That way we don't need to enable one over the other and >>> will continue supporting all existing functionality while extending it for devices >>> with UFS/eMMC storage and running upstream Linux. >>> >>> Do let me know your opinion on it. >> >> My opinion is very obvious by now. Existing devices should work. _Must_ >> work. They provide the reference interface. Make them work first and >> work good. Then explain, why the other interface is better (I fail to >> see it from your cover letter or from any of the commit messages). >> >> When I take a Glumur laptop from the market shelf, will it be QSEECOM or >> QCOMTEE? If I take the next-generation-after-Glymur, will QTEE interface >> for uefisecapp be supported there? Will it be used by Windows? >> >> I think the series fails to answer, why do we need another mechanism, if >> we already have one which has been working for the past N years and >> which is supposed to work for another M years? >> > > At this point, we have the following categories of devices: > 1. Devices with only QSEECOM support, but no support for callbacks/RPMB listener within > Linux QSEECOM driver. > Example, MSM8998 and older WoA laptops. These are very old devices (at least more than > 6-7 years old). > > 2. Devices with both QSEECOM and SMCInvoke/QCOMTEE support. > Example, SM8650, *Glymur*. These are relatively new devices (2-5 years old). > > 3. Devices with only SMCInvoke/QCOMTEE support. > Example, RB3Gen2/Kodiak, IQ-9075/LeMans and newer devices which might not have > QSEECOM support in the future since QTEE team has deprecated QSEECOM. > > This patch series helps devices in category 2 and 3. Without the mechanism introduced > by this series, we will end up in a situation where EFI variable based use-cases will > become impossible on at least category 3 of devices. We must conform to the reality > that QTEE firmware is transitioning to SMCInvoke as the protocol of choice with > long-term committed support. > > At the same time, I am aligned that we must think of a way to support devices in category 1 > which is what you really care about. The QCOMTEE and QSEECOM drivers can co-exist, and so > by adding support for both this patch series and callback requests to the QSEECOM driver > (at a later point of time via a separate series) we will be able to provide EFI variable > support on all Qualcomm platforms under the sun. This will accomplish our common goal. > > I will add this information in the cover letter in a concise manner. > >>>> What about other existing devices? We have WoA devices starting with >>>> MSM8998. The QSEECOM driver works on them, but, as you mentioned, it >>>> can't flash updates to the backing storage. >>>> >>> >>> Unfortunately, unless we roll out new QTEE firmware versions for devices like MSM8998 >>> with QCOMTEE/SMCInvoke support + access to the Uefisecapp over SMCInvoke protocol, >>> they cannot be helped with this series. >> >> So, I'd say, the series is strange. We are proposing something which is >> not rolled out, which is not supported by the exsiting commercial >> devices, etc. On the other hand we have future gaps which are known. >> This doesn't sound correctly. >> > > We are proposing a mechanism which supports the majority of Qualcomm devices in the market > launched within the last 5 years and also the upcoming ones. The category of devices which > are not helped by this series are extremely old (at least 6+ years). Regardless, I am not > pushing the view that we do not care about those devices, just that the route to helping > them is different and orthogonal to this series and I am happy to engage on it separately. >>>>> I need to double-check but this firmware release for Glymur on Qualcomm Linux >>>>> is probably carrying the support for QCOMTEE based uefisecapp access: >>>>> https://github.com/qualcomm-linux/meta-qcom/commit/728251fcbe5113980805ea6c571e33235062ee71 >>>>> If not, the next release will definitely have it since I have merged support for >>>>> this in QTEE and talked to the boot firmware release team about this. >>>> >>>> Does it work on the CRD? >>>> >>> >>> Yes it does, I have validated on Glymur CRD by locally switching it from the current QSEECOM >>> based uefisecapp to this new QCOMTEE based uefisecapp. This is the QTEE release which >> >> Why do we need to switch the app? Why is the old one worth switching? >> > > You do not need to, Glymur supports both QSEECOM and QCOMTEE/SMCInvoke. I just used Glymur > as an example to show that both work there and if a user wants he can chose one over the other > (It really doesn't matter). Glymur sits in the middle of the old and the new, it is a category 2 > device as mentioned above. >>> needs to be consumed for it: >>> https://github.com/qualcomm-linux/meta-qcom/commit/5590c1dc631827624c110df282965b85ef2a2e60 >>> >>>>> >>>>> The next planned firmware upgrade for Hamoa will also provide this support for >>>>> Qualcomm Linux. And similarly, for all other targets being supported upstream. >>>> >>>> So, we are forcing users to upgrade to the new firmware? That doesn't >>>> sound nice. >>>> >>> >>> We have an open ecosystem for all devices supported by the Qualcomm Linux distribution, >>> users can easily consume new releases (and new QTEE versions) to access new features. >>> Until now, developers/users of RB3Gen2 or IQ-9075 could not access EFI variables to >> >> What stopped us from delivering the TZ apps compatible with the existing >> interface? >> > > QSEECOM support is deprecated on IQ-9075 and broken on RB3Gen2. > >>> develop use-cases such as secure-boot key revocation, but by taking this patch series >>> as part of a subsequent Qualcomm Linux release, they will be able to. >>> >>>>>>> Thus, QCOMTEE now maintains a static list of always-available object-IPC >>>>>>> based secure services exposed by QTEE. These services are implemented either >>>>>>> within the QTEE kernel or within a pre-loaded Trusted Application (TA) >>>>>>> usually loaded by the bootloader. The uefisecapp TA is an example of a >>>>>>> preloaded TA loaded by UEFI. A static list is required since QTEE does not >>>>>>> yet expose any way to dynamically query and enumerate the services exposed by >>>>>>> it. >>>>>> >>>>>> Can it be fixed instead of having static lists? In the end, we can't >>>>>> guarantee that users update the firmware. >>>>>> >>>>> >>>>> Unfortunately, no existing QTEE release out there currently has this support. >>>>> But support for this is currently being added by QTEE team last I checked with them. >>>>> Once it is available, and a new QTEE firmware release is out there, we will add >>>>> support for dynamically querying QTEE services in the QCOMTEE driver. >>>> >>>> It seems you are still rolling out QTEE-based support. In such a case, >>>> please go back and implement dynamic detection of QTEE services. >>>> Otherwise it would be a nightmare. >>>> >>> >>> We are working on it, but until then there is no overhead involved in maintaining >>> this static list of services because we don't have to extend/modify this list when >>> adding support for a new Qualcomm platform upstream. If a particular service from >>> the list is not implemented/accessible from QTEE we log the event and silently avoid >>> probing the TEE driver for the service. We also don't add platform specific services >>> here. So the list doesn't need to be extended on a per-platform basis. >>> >>> So unlike the QSEECOM driver, we don't have to keep maintaining this list forever >>> for all new platforms. >> >> I don't see a difference. You are saying that the list implementation is >> good, it silintly skips the unavailable services, etc., and then you say >> that you don't have to keep maintaining the list. >> > > We only have to add services to this list when a client driver appears for it. For > example, this TPM series by Kuldeep: > https://lore.kernel.org/all/20260831-tpm_qcom_driver-v1-1-6f16fa6924fa@oss.qualcomm.com/ > > We don't need to maintain this list on a per-platform basis unlike QSEECOM: > https://elixir.bootlin.com/linux/v7.2-rc7/source/drivers/firmware/qcom/qcom_scm.c#L2289 > > Support will arrive for dynamic detection, I have commitment from QTEE team for somewhere > around end of the year. :) > >>>>>>> To facilitate object-IPC interactions from the kernel-space, this >>>>>>> series also introduces a tee_client_object_invoke_func() to allow >>>>>>> invocation of TEE objects similar to the existing tee_client_invoke_func() >>>>>>> API exported by the TEE subsystem which allows invocation of TEE functions. >>>>>>> Some suporting changes are also introduced to track and handle operations >>>>>>> for TEE contexts opened from the kernel-space in the back-end QCOM-TEE >>>>>>> driver. >>>>>>> >>>>>>> Finally and as previously mentioned, access to the object-IPC based uefisecapp >>>>>>> service is restricted on older QTEE firmware versions. A new QTEE firmware >>>>>>> release must be picked up from QArtifactory [2] for all upstream supported >>>>>>> Qualcomm SoCs to enable access to uefisecapp service via the TEE client >>>>>>> driver. >>>>>> >>>>>> What about fused devices? >>>>> >>>>> The procedure for updating the firmware on fused devices is slightly different. >>>>> The firmware images need to be signed by the OEM using the security profile >>>>> of the chipset before flashing/upgrading them. Security profiles are now public: >>>>> https://github.com/qualcomm/security-profiles >>>> >>>> Will OEMs release new firmware images? What about the devices which are >>>> already out of the support phase? This whole story rotates about the 'we >>>> are releasing new firmware with new features' paradigm. However there >>>> are existing devices in the field, which typically can't be upgraded, >>>> From your cover letter it seems they can't support UEFI variables >>>> properly. However they do so in Windows. >>>> >>> >>> Yes Dmitry, this series is effectively forward looking. QSEECOM protocol/driver >>> support is essentially deprecated on QTEE side, no new features added to QTEE support >>> it, and it also doesn't work on many devices like the RB3Gen2. >> >> To look forward, we need to have a good firm stand on the ground. We >> have a half-baked implementation, based on reverse engineering. No RPMB >> support, etc. >> > > Agreed. I am happy to engage on a separate series for adding callback support to QSEECOM > driver along with RPMB listener within the kernel. > >>> For existing devices, if they boot with upstream Linux and have RPMB located on >>> UFS/eMMC this patch series cannot help them. But the focus of this series is not on the >>> past, it is on currently supported and future hardware. Every new Qualcomm platform >>> whose support is being up-streamed or is planned to be up-streamed will have access to >>> EFI variables via this series. >>> >>> If someone wants to add support for older Qualcomm devices to access EFI variables >>> via QSEECOM that patch series will not conflict with this one. Like I said, both >>> QSEECOM and QCOMTEE based drivers can co-exist. >> >> What will happen if I build both and boot the kernel on the existing >> devices? >> > > QSEECOM and its client driver probe first and establishes the path to uefisecapp for > providing EFI variables service. QCOMTEE and its client silently fail probe. > > Regards, > Harshal > >