On 8/31/2026 3:02 PM, Krzysztof Kozlowski wrote:
> On 27/08/2026 18:07, Linlin Zhang wrote:
>> From: linlzhan <[email protected]>
>>
>> On Qualcomm platforms the ICE hardware has a fixed number of physical
>> keyslots shared across the host and all guest VMs. A userspace
>> virtio-blk backend handling VIRTIO_BLK_T_CRYPTO_IN/OUT requests needs
>> to translate a guest's virtual keyslot index to the corresponding
>> physical ICE keyslot without letting one VM access another VM's slots.
>>
>> Add QCOM_ICE_SLOTS, a platform driver that implements bcp_slot_virt_ops
>> for the /dev/blk-crypto-proxy device. It parses a
>> qcom,ice-keyslot-map device-tree node describing the per-VM keyslot
>> allocation table, where each child entry maps a guest_id to a
>> contiguous physical slot range [slot_offset .. slot_offset +
>> max_ice_slots). Entry 0 is reserved for the host; guest entries start
>> at index 1 and are excluded from the guest-facing translation so that
>> blk-crypto-proxy cannot accidentally route a guest request into the
>> host's physical keyslots.
>>
>> The driver exposes two callbacks:
>>
>> get_guest_slots() — return the number of ICE keyslots allocated to
>> a given guest_id; used by BCP_GET_CRYPTO_CAPS to
>> populate the max_slots field in the virtio config
>> space.
>> vslot_to_pslot() — translate a (guest_id, virtual-slot) pair to the
>> corresponding physical ICE keyslot index; used by
>> BCP_SUBMIT_IO_BY_VSLOT before calling
>> bio_crypt_set_ctx_by_slot().
>>
>> The singleton pointer to the parsed table is RCU-protected; the hot
>> path reads it lock-free. Probe validates that no two VM entries share
>> a guest_id or overlapping physical slot ranges.
>>
>> Note: This patch is submitted for visibility. The keyslot partitioning
>> is based on the current DT-based keyslot allocation with vm_id known.
>> We are aware this may be revised to use a TZ SCM query interface in a
>> future version of this series, submit it RFC for design discussion.
>>
>> Signed-off-by: linlzhan <[email protected]>
>> ---
>> drivers/soc/qcom/Kconfig | 18 +++
>> drivers/soc/qcom/Makefile | 1 +
>> drivers/soc/qcom/qcom_ice_slots.c | 232 ++++++++++++++++++++++++++++++
>> 3 files changed, 251 insertions(+)
>> create mode 100644 drivers/soc/qcom/qcom_ice_slots.c
>>
>> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
>> index 6c632d114d45..e1f383b4dc63 100644
>> --- a/drivers/soc/qcom/Kconfig
>> +++ b/drivers/soc/qcom/Kconfig
>> @@ -294,6 +294,24 @@ endif
>> # Options selected by other drivers from different subsystems must be
>> outside
>> # of the menuconfig if-block:
>>
>> +config QCOM_ICE_SLOTS
>> + tristate "Qualcomm ICE keyslot partitioning for VM guests"
>> + depends on ARCH_QCOM || COMPILE_TEST
>> + depends on BLK_CRYPTO_PROXY
>> + depends on BLK_INLINE_ENCRYPTION
>> + help
>> + Parses the qcom,ice-keyslot-map device-tree node and provides
>> + per-VM ICE keyslot accounting and virtual-to-physical slot
>> + translation for guest VMs sharing ICE hardware on Qualcomm
>> + platforms.
>> +
>> + When enabled, guest virtual keyslot indices are mapped to the
>> + physical ICE keyslot range allocated to each VM, preventing one
>> + VM from accessing another VM's keyslots.
>> +
>> + Say M here when multiple VMs share ICE keyslots on a Qualcomm
>> + platform. If unsure, say N.
>> +
>> config QCOM_INLINE_CRYPTO_ENGINE
>> tristate
>> select QCOM_SCM
>> diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
>> index 6d4b7546d1fb..952a57554f9d 100644
>> --- a/drivers/soc/qcom/Makefile
>> +++ b/drivers/soc/qcom/Makefile
>> @@ -38,6 +38,7 @@ obj-$(CONFIG_QCOM_LLCC) += llcc-qcom.o
>> obj-$(CONFIG_QCOM_KRYO_L2_ACCESSORS) += kryo-l2-accessors.o
>> obj-$(CONFIG_QCOM_ICC_BWMON) += icc-bwmon.o
>> qcom_ice-objs += ice.o
>> +obj-$(CONFIG_QCOM_ICE_SLOTS) += qcom_ice_slots.o
>> obj-$(CONFIG_QCOM_INLINE_CRYPTO_ENGINE) += qcom_ice.o
>> obj-$(CONFIG_QCOM_CRYPTO_VIRT) += crypto_virt.o
>> obj-$(CONFIG_QCOM_PBS) += qcom-pbs.o
>> diff --git a/drivers/soc/qcom/qcom_ice_slots.c
>> b/drivers/soc/qcom/qcom_ice_slots.c
>> new file mode 100644
>> index 000000000000..364ac93077c1
>> --- /dev/null
>> +++ b/drivers/soc/qcom/qcom_ice_slots.c
>> @@ -0,0 +1,232 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * qcom_ice_slots.c - Qualcomm ICE keyslot partitioning for guest VMs
>> + *
>> + * Implements bcp_slot_virt_ops: translates a (guest_id, virtual-slot) pair
>> to
>> + * a physical ICE keyslot index using a per-VM allocation table parsed from
>> + * the device-tree node with compatible = "qcom,ice-keyslot-map".
>> + *
>> + * Device-tree layout:
>> + *
>> + * ice_keyslot_map: ice-keyslot-map {
>> + * compatible = "qcom,ice-keyslot-map";
>
> NAK, there is no such stuff.
>
> Drivers for undocumented downstream DTS are not allowed.
>
ACK
This is used to set slot mapping table in DT node. It will be moved
to Trust Zone if current out-of-band key operation is approved. Otherwise,
if virtio block devices implement blk_crypto_ops, this driver is unnecessary.
> ...
>
>> +
>> + dev_info(dev, "registered: %u VMs, %u total ICE slots\n",
>> + idx, total_slots);
>
> This does not look like useful printk message. Drivers should be silent
> on success:
> https://elixir.bootlin.com/linux/v6.15-rc7/source/Documentation/process/coding-style.rst#L913
> https://elixir.bootlin.com/linux/v6.15-rc7/source/Documentation/process/debugging/driver_development_debugging_guide.rst#L79
ACK
>
>
> Best regards,
> Krzysztof
