Dear all,
Tomorrow, Tuesday July 28th, 8am UTC, is the next OP-TEE Public Meeting.
For time and connection details, see the calendar at:
https://www.trustedfirmware.org/meetings
There are no specific topics to the agenda but feel free to join and raise any question or share any topic you want, or just attend in case some discussed topics may interest you.
Sorry for the short notice.
Regards,
Etienne Carriere
'select' does not work on config options in a 'choice', so currently it is
possible to enable QCOMTEE without QCOM_TZMEM_MODE_SHMBRIDGE.
This patch removes the select.
I've compile-tested this and found that it builds fine without
QCOM_TZMEM_MODE_SHMBRIDGE, but I don't have the hardware to runtime test.
Please advise if it would be better to make QCOM_TZMEM_MODE_SHMBRIDGE a
dependency.
This dead select was found by kconfirm, a static analysis tool for Kconfig.
Signed-off-by: Julian Braha <julianbraha(a)gmail.com>
---
drivers/tee/qcomtee/Kconfig | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/tee/qcomtee/Kconfig b/drivers/tee/qcomtee/Kconfig
index 9f19dee08db4..00e07ed80138 100644
--- a/drivers/tee/qcomtee/Kconfig
+++ b/drivers/tee/qcomtee/Kconfig
@@ -5,7 +5,6 @@ config QCOMTEE
depends on ARCH_QCOM || COMPILE_TEST
depends on !CPU_BIG_ENDIAN
select QCOM_SCM
- select QCOM_TZMEM_MODE_SHMBRIDGE
help
This option enables the Qualcomm Trusted Execution Environment (QTEE)
driver. It provides an API to access services offered by QTEE and
--
2.54.0
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).
For Qualcomm platforms without emulated RPMB support, specifically
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]).
Unlike the QCOM-TEE driver, the QSEECOM driver (used by the current
QSEECOM based uefisecapp) does not support callback requests. And on
certain Qualcomm platforms such as the RB3Gen2, attempts to access the
QSEECOM interface fail due to lack of support within Qualcomm TEE.
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.
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.
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 along with associated changes in user-space libqcomtee via Pull
Request [3].
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.
This patch series has been validated on Kodiak RB3Gen2 platform with UFS
storage by attempting to read/write EFI variables via the efivar tool [4]
after mounting the efivarfs filesystem. See [5] for an example.
Merge Strategy:
This patch series could either be taken from the OP-TEE tree or the
QCOM soc tree. I would prefer it to be picked by the OP-TEE tree since
all except the uefisecapp TEE client driver patch in this series make
changes relevant to the TEE subsystem. It would be great if the QCOM soc
tree maintainers can Ack the uefisecapp driver patch.
[1] https://github.com/qualcomm/minkipc
[2] https://shorturl.at/zQU07
[3] https://github.com/quic/quic-teec/pull/27
[4] https://github.com/rhboot/efivar
[5] https://docs.qualcomm.com/doc/80-70020-27/topic/manage_uefi_environment_var…
Signed-off-by: Harshal Dev <harshal.dev(a)oss.qualcomm.com>
---
Amirreza Zarrabi (2):
tee: Add kernel client object invoke helper
tee: qcomtee: Allow object invokes from kernel clients
Harshal Dev (4):
tee: qcomtee: Track the object invocation context
tee: Export uuidv5 generation for TEE clients
tee: qcomtee: Add support for registering QTEE services on TEE bus
firmware: qcom: Add support for TEE based EFI-var client driver
MAINTAINERS | 7 +
drivers/firmware/qcom/Kconfig | 24 ++
drivers/firmware/qcom/Makefile | 1 +
drivers/firmware/qcom/qcom_tee_uefisecapp.c | 525 ++++++++++++++++++++++++++++
drivers/firmware/qcom/qcom_tee_uefisecapp.h | 120 +++++++
drivers/tee/qcomtee/call.c | 218 +++++++++++-
drivers/tee/qcomtee/core.c | 9 +-
drivers/tee/qcomtee/qcomtee.h | 18 +
drivers/tee/qcomtee/qcomtee_msg.h | 1 +
drivers/tee/qcomtee/qcomtee_object.h | 16 +-
drivers/tee/tee_core.c | 26 +-
include/linux/tee_core.h | 15 +
include/linux/tee_drv.h | 18 +-
13 files changed, 968 insertions(+), 30 deletions(-)
---
base-commit: f3e6330d7fe42b204af05a2dbc68b379e0ad179e
change-id: 20260408-qcom_uefisecapp_migrate_qcomtee-13869d45e014
Best regards,
--
Harshal Dev <harshal.dev(a)oss.qualcomm.com>
This series makes UFS RPMB work out of the box with an OP-TEE that
implements the standard eMMC RPMB key-derivation flow, without requiring
any fundamental changes on the OP-TEE side.
RPMB provides an authenticated, replay-protected storage area whose
security relies on a secret authentication key. In our setup that key is
never exposed to the kernel: OP-TEE derives it in the secure world from
its hardware-unique key and a device identifier (dev_id) that the RPMB
core hands down. OP-TEE's implementation targets eMMC, where dev_id is
the 16-byte eMMC CID, and both the fixed length and the raw-CID layout
are baked into its key derivation.
Two things stand in the way of reusing that same, unmodified OP-TEE flow
for UFS RPMB:
1. On a cold boot the very first frame sent to the RPMB well-known LU
comes back with a power-on UNIT ATTENTION (ASC 0x29), which the SCSI
core reports rather than retries. RPMB has no earlier guaranteed
access that could clear the condition first, so RPMB fails on every
power cycle. Patch 1 asks the SCSI core to retry the power-on UNIT
ATTENTION on the RPMB WLUN.
2. The UFS RPMB id is "<device_id>-R<region>", which is variable length
and longer than 16 bytes. Passing it verbatim would tie the derived
key to a length OP-TEE does not expect and diverge from the fixed
eMMC CID ABI. Patch 2 hashes it into a fixed 16-byte dev_id with
blake2s, keeping the key stable and unique per region while matching
the eMMC CID layout OP-TEE relies on. The hash algorithm and input
string are thus part of the key-derivation ABI and must stay stable.
With both patches, UFS RPMB is functional from the first access after a
cold boot and derives keys through the existing eMMC-style OP-TEE flow,
(requires minimal OP-TEE changes pending on the CID proposal done here).
Tested on IQ-9075 with Open Firmware [1], pending OP-TEE changes
[1]https://ldts.github.io/qcom-buildroot
v1:
* ufs: rpmb: retry power-on UNIT ATTENTION on the RPMB WLUN:
- fix using uses SCMD_FAILURE_ASC_ANY to retry any Unit Attention
- fix unused variable
* ufs: rpmb: use a fixed-length RPMB dev_id
- fix selecting a non-existent Kconfig symbol
Jorge Ramirez-Ortiz (2):
ufs: rpmb: retry power-on UNIT ATTENTION on the RPMB WLUN
ufs: rpmb: use a fixed-length RPMB dev_id
drivers/ufs/core/ufs-rpmb.c | 39 ++++++++++++++++++++++++++++++++++---
1 file changed, 36 insertions(+), 3 deletions(-)
--
2.54.0
I have been reviewing how OP‑TEE is implemented and how secure‑world
invocations behave. The goal was to determine whether an OP‑TEE call can
delay the Linux side and introduce latency depending on the time spent
in the secure world.
Similar latency effects are already known for EFI runtime services, but
this was not documented. To mitigate the impact, EFI runtime invocations
can be restricted to specific CPUs so that real‑time workloads on other
CPUs remain unaffected. This mechanism, however, is only described in
the commit that introduced it.
This change adds a firmware section that documents these behaviours
explicitly. It highlights cases where firmware can delay the kernel,
information that may be unfamiliar to some users and surprising-or
concerning-to others.
Assisted-by: Microsoft-Copilot
Signed-off-by: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de>
---
I would appreciate an ACK from the OP-TEE camp that I got my little
research right.
Documentation/core-api/real-time/hardware.rst | 92 +++++++++++++++++++
1 file changed, 92 insertions(+)
diff --git a/Documentation/core-api/real-time/hardware.rst b/Documentation/core-api/real-time/hardware.rst
index 19f9bb3786e03..fb113848c2f70 100644
--- a/Documentation/core-api/real-time/hardware.rst
+++ b/Documentation/core-api/real-time/hardware.rst
@@ -130,3 +130,95 @@ https://github.com/Linutronix/RTC-Testbench.
The goal of this project is to validate real-time network communication. It can
be thought of as a "cyclictest" for networking and also serves as a starting
point for application development.
+
+Firmware
+--------
+
+The firmware often plays a significant role in system operation because it can
+perform tasks that the kernel cannot directly access, and in some cases it can
+even preempt or intercept the kernel.
+
+A common example of firmware assisting the kernel is when it provides a generic
+interface to a resource. Instead of accessing an RTC chip through an I2C host
+controller, the kernel may query the firmware for the current time, and the
+firmware then accesses the RTC behind the scenes.
+
+Firmware can also intercept kernel execution by providing services that
+temporarily take control of the system. One example is memory scrubbing, where
+the firmware periodically pauses the kernel, reads back portions of system
+memory, and then returns control. During this time, the kernel is effectively
+interrupted.
+In contrast, some systems provide hardware‑based memory scrubbing, which
+operates independently of firmware or software. See
+Documentation/edac/scrub.rst for details.
+
+If the kernel is intercepted for longer periods then these periods can be made
+visible with the hardware latency detector. See
+Documentation/trace/hwlat_detector.rst.
+
+The kernel can also be intercepted in response to specific events, such as
+overheating. In this case, the firmware may throttle the CPU or shut it down
+immediately to prevent hardware damage.
+
+Unless the firmware is well documented, it should be thoroughly tested to
+uncover any unexpected behaviour.
+
+EFI
+~~~~
+
+EFI provides runtime services that act as a communication interface between the
+firmware and the operating system. One such service is reading and writing EFI
+variables, which are used, for example, to determine the boot source.
+
+Invoking a runtime service may require the architecture to disable kernel
+preemption or interrupts during the call. This means the duration of a service
+invocation directly affects the system’s observable latency. There is also
+nothing that prevents a service call from disabling interrupts internally while
+it runs.
+
+For these reasons, EFI runtime services are disabled by default on a PREEMPT_RT
+kernel. They can still be enabled at boot time or via a Kconfig option if
+required.
+The native EFI runtime service implementation (where both the EFI service and
+the kernel are either 32‑bit or 64‑bit executables) uses a wrapper mechanism
+that invokes the service through a dedicated workqueue. This workqueue is named
+efi_runtime, and it can be restricted to a housekeeping CPU using the
+``/sys/devices/virtual/workqueue/efi_runtime/cpumask`` sysfs file. Assigning it
+to a housekeeping CPU ensures that potentially long service invocations do not
+impact the real‑time workload which is restricted to other CPUs.
+
+It must also be verified that the runtime services behave as expected. Some
+implementations on the x86 architecture pause all other CPUs while one CPU
+performs the service call. In such cases, the interruption affects all CPUs,
+and restricting the workqueue to a single CPU provides no benefit.
+
+OP-TEE (ARM)
+~~~~~~~~~~~~
+
+OP‑TEE uses a global serialization mechanism (the "big lock"), ensuring that on
+each core only one OP‑TEE thread executes secure‑world code at a time.
+
+Execution flows from the normal world (Linux) into the secure world (OP‑TEE)
+through the secure monitor at EL3. Linux and OP‑TEE cannot disable or mask each
+other’s interrupts because both run at EL1 in different security states.
+
+Architecturally, the secure monitor can mask or reroute normal‑world interrupts
+before entering the secure world. In a correct OP‑TEE/ TF‑A implementation, it
+does not do this for the duration of secure calls. Normal‑world interrupts
+remain deliverable, and a normal‑world IRQ will preempt OP‑TEE via EL3 and
+return control to Linux.
+
+Secure‑world interrupts (FIQs) are possible if the SoC routes a device's
+interrupt as secure. Such a secure FIQ will preempt Linux immediately, trap
+into EL3, and transfer control to OP‑TEE's secure interrupt handler. Linux
+cannot mask or preempt this. Secure FIQ handlers must therefore be extremely
+short to avoid introducing noticeable latency.
+
+The transition from normal world -> secure monitor -> OP‑TEE and back introduces
+additional latency due to world switching and context save/ restore. This
+overhead is typically a few microseconds and usually remains in the noise
+floor.
+
+If the secure monitor masks normal‑world interrupts during OP‑TEE invocations,
+or if OP‑TEE uses long‑running secure FIQ handlers, then OP‑TEE can introduce
+measurable latency spikes.
--
2.53.0
Hi op-tee team,
As part of the Arm bug bounty, we’ve recently sent a few messages to op-tee-security. Unfortunately we haven’t had any responses since Jens left Linaro.
Please could we ask who remains on this list so that we can reach out to them directly?
Many thanks,
Arm PSIRT
Hi all,
This series fixes the Endpoint Memory Access Descriptor (EMAD) offset
calculations and adds the necessary bounds checks for both the core
FF-A driver and the pKVM hypervisor.
Prior to FF-A version 1.1, the memory region header didn't specify an
explicit offset for the EMADs, leading to the assumption that they
immediately follow the header.
However, from v1.1 onwards, the specification dictates using the
ep_mem_offset` field to determine the start of the memory access
array.
The patches in this series address this by:
1. Updating the core `arm_ffa` firmware driver to correctly calculate
the descriptor
offset using `ep_mem_offset` rather than defaulting to `sizeof(struct
ffa_mem_region)`.
It also introduces bounds checking against `max_fragsize`.
2. Enhancing the pKVM hypervisor validation logic to no longer strictly
enforce that
the descriptor strictly follows the header, aligning it with the
driver behavior
and the FF-A specification, while also ensuring the offset falls
within the mailbox
buffer bounds.
While addressing these bugs, Sashiko uncovered other issues that were
fixed in the same series.
All the patches aside from the first one in optee are urgent fixes as
they either impact the hypervisor security or kernel stability.
Changelog
#########
v8->v9:
- addressed Sashiko double ffa_rx_release in "KVM: arm64: Fix bounds
checking in do_ffa_mem_reclaim()"
v7->v8:
- dropped the patch "optee: ffa: Add NULL check in
optee_ffa_lend_protmem" from the series as it was queued by Jens
- rephrased the commit message for "KVM: arm64: Ensure FFA ranges are
page aligned"
- introduced a helper macro to get the size of the ffa memory region
based on the used version.
v6->v7:
- taking the patches from Mostafa and sending a new version with the
collected tags
- Added overflow checks when doing `ep_offset + emad_size` in the arm
ff-a driver
- Move the length check before the ffa_mem_reclaim
- fix compatibility break with ff-a version 1.0 reported by Sashiko
- add one more patch to fix an issue with the FFA_VERSION call
that can lead to leaking pKVM stack un-initialized data to
a host when -ftrivial-auto-var-init=zero is not used.
v5->v6:
- Add fixes tag
- Small clean up make variable declaration reverse christmas tree.
v4->v5:
- Collect Sudeep Rbs
- Add extra patch to check base address alignment.
- Remove WARN_ONs in KVM code
- Use ffa_emad_size_get() instead of hardcoded size in KVM code.
v3 -> v4:
- Address review comments and fix Sashiko bugs
v2 -> v3:
- Fixed typo in nvhe/ffa.c (missing sizeof)
v1 -> v2:
- For pKVM, removed the strict placement enforcement for `ep_mem_offset`
as it is not
compliant with the spec, and avoids making assumptions about the
driver's memory
layout.
Link to:
########
v8: https://lore.kernel.org/all/20260630102058.3219867-2-sebastianene@google.co…
v7: https://lore.kernel.org/all/20260617145130.3729015-1-sebastianene@google.co…
v6: https://lore.kernel.org/all/20260527150236.1978655-1-smostafa@google.com/
v5: https://lore.kernel.org/all/20260526151934.3783707-1-smostafa@google.com/
v4: https://lore.kernel.org/all/20260520204948.2440882-1-smostafa@google.com/
v3: https://lore.kernel.org/all/20260512124442.1899107-1-sebastianene@google.co…
v2: https://lore.kernel.org/all/20260430160241.1934777-1-sebastianene@google.co…
v1: https://lore.kernel.org/all/ae9KN9nkOgDYJcGP@google.com/T/#t
Mostafa Saleh (3):
firmware: arm_ffa: Fix out-of-bound writes in ffa_setup_and_transmit()
KVM: arm64: Fix bounds checking in do_ffa_mem_reclaim()
KVM: arm64: Ensure FFA ranges are page aligned
Sebastian Ene (3):
firmware: arm_ffa: Fix Endpoint Memory Access Descriptor offset
calculation
KVM: arm64: Validate the offset to the mem access descriptor
KVM: arm64: Zero out the stack initialized data in the FFA handler
arch/arm64/kvm/hyp/nvhe/ffa.c | 44 +++++++++++++++++++++----------
drivers/firmware/arm_ffa/driver.c | 25 ++++++++++++------
include/linux/arm_ffa.h | 9 ++++++-
3 files changed, 55 insertions(+), 23 deletions(-)
--
2.55.0.rc0.799.gd6f94ed593-goog