Re: [PATCH v17 1/7] firmware: arm_rmm: Add SMC definitions for calling the RMM

[Gavin Shan <gshan@redhat.com>]

On 9/8/26 8:37 PM, Suzuki K Poulose wrote:
> On 08/09/2026 07:19, Gavin Shan wrote:
>> On 9/7/26 7:59 PM, Suzuki K Poulose wrote:
>>> From: Steven Price <steven.price@arm.com>
>>>
>>> The RMM (Realm Management Monitor) provides functionality that can be
>>> accessed by SMC calls from the host.
>>>
>>> The SMC definitions are based on DEN0137[1] version 2.0-bet3
>>>
>>> [1] https://developer.arm.com/documentation/den0137/2-0bet3/
>>>
>>> Signed-off-by: Steven Price <steven.price@arm.com>
>>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> 
> ...
> 
>>> ---
>>>   include/linux/arm-smccc-rmi.h | 494 ++++++++++++++++++++++++++++++++++
>>>   1 file changed, 494 insertions(+)
>>>   create mode 100644 include/linux/arm-smccc-rmi.h
>>>
>>
>> Some nitpicks below, please pick up the commits that look reasonable :)
>>
> 
> 
>>> +
>>> +#define RMI_RETURN_STATUS_MASK        (0xFFUL)
>>> +#define RMI_RETURN_INDEX_MASK        (0xFFUL << 8)
>>> +#define RMI_RETURN_MEMREQ_MASK        (0x3UL << 8)
>>> +#define RMI_RETURN_CAN_CANCEL_MASK    (0x1UL << 10)
>>> +
>>> +#define RMI_RETURN_STATUS(ret) FIELD_GET(RMI_RETURN_STATUS_MASK, ret)
>>> +#define RMI_RETURN_INDEX(ret)        FIELD_GET(RMI_RETURN_INDEX_MASK, ret)
>>> +#define RMI_RETURN_MEMREQ(ret) FIELD_GET(RMI_RETURN_MEMREQ_MASK, ret)
>>> +#define RMI_RETURN_CAN_CANCEL(ret) FIELD_GET(RMI_RETURN_CAN_CANCEL_MASK, ret)
>>> +
>>
>> If I'm correct enough, RMI_RETURN_{STATUS, INDEX, MEMREQ, CAN_CANEL} _MASK are used
>> for once in this header file. So we needn't explicitly expose them and combine their
>> definitions with users to fetch the corresponding fields, as below.
>>
>> #define RMI_RETURN_STATUS(ret)        FIELD_GET(GENMASK(7, 0), ret)
>> #define RMI_RETURN_INDEX(ret)        FIELD_GET(GENMASK(15, 8), ret)
>> #define RMI_RETURN_MEMREQ(ret)        FIELD_GET(GENMASK(10, 8), ret)
>> #define RMI_RETURN_CAN_CANCEL(ret)    FIELD_GEt(GENMASK(10, 10), ret)
> 
> I belive the header files were generated from a tool (by Steven) and
> these would make it easier to compare with the generated header file for
> any deviation from the spec. So, I am a bit reluctant make these
> changes.
> 
> That said, I am happy to convert the mask definitions to GENMASK() for
> consistency and readability. i.e., something like:
> 
> diff --git a/include/linux/arm-smccc-rmi.h b/include/linux/arm-smccc-rmi.h
> index 3eb88caf40964..078197284415e 100644
> --- a/include/linux/arm-smccc-rmi.h
> +++ b/include/linux/arm-smccc-rmi.h
> @@ -139,10 +139,10 @@
>   #define RMI_ABI_VERSION_GET_MINOR(version) ((version) & 0xFFFF)
>   #define RMI_ABI_VERSION(major, minor)      (((major) << 16) | (minor))
> 
> -#define RMI_RETURN_STATUS_MASK         (0xFFUL)
> -#define RMI_RETURN_INDEX_MASK          (0xFFUL << 8)
> -#define RMI_RETURN_MEMREQ_MASK         (0x3UL << 8)
> -#define RMI_RETURN_CAN_CANCEL_MASK     (0x1UL << 10)
> +#define RMI_RETURN_STATUS_MASK         GENMASK(7, 0)
> +#define RMI_RETURN_INDEX_MASK          GENMASK(15, 8)
> +#define RMI_RETURN_MEMREQ_MASK         GENMASK(10, 8)
> +#define RMI_RETURN_CAN_CANCEL_MASK     BIT(10)
> 

Ok.

>>
>>> +#define RMI_SUCCESS            0
>>> +#define RMI_ERROR_INPUT            1
>>> +#define RMI_ERROR_REALM            2
>>> +#define RMI_ERROR_REC            3
>>> +#define RMI_ERROR_RTT            4
>>> +#define RMI_ERROR_NOT_SUPPORTED        5
>>> +#define RMI_ERROR_DEVICE        6
>>> +#define RMI_ERROR_RTT_AUX        7
>>> +#define RMI_ERROR_PSMMU_ST        8
>>> +#define RMI_ERROR_DPT            9
>>> +#define RMI_BUSY            10
>>> +#define RMI_ERROR_GLOBAL        11
>>> +#define RMI_ERROR_TRACKING        12
>>> +#define RMI_INCOMPLETE            13
>>> +#define RMI_BLOCKED            14
>>> +#define RMI_ERROR_GPT            15
>>> +#define RMI_ERROR_GRANULE        16
>>> +
>>> +#define RMI_CONTINUE_KEEP_GOING        0
>>> +#define RMI_CONTINUE_STOP        1
>>> +
>>> +#define RMI_OP_MEM_REQ_NONE        0
>>> +#define RMI_OP_MEM_REQ_DONATE        1
>>> +#define RMI_OP_MEM_REQ_RECLAIM        2
>>> +
>>> +#define RMI_DONATE_SIZE_MASK        3UL
>>> +#define RMI_DONATE_COUNT_MASK        GENMASK(15, 2)
>>> +#define RMI_DONATE_CONTIG_MASK        BIT(16)
>>> +#define RMI_DONATE_STATE_MASK        GENMASK(18, 17)
>>> +
>>> +#define RMI_DONATE_SIZE(req)        FIELD_GET(RMI_DONATE_SIZE_MASK, req)
>>> +#define RMI_DONATE_COUNT(req)        FIELD_GET(RMI_DONATE_COUNT_MASK, req)
>>> +#define RMI_DONATE_CONTIG(req) FIELD_GET(RMI_DONATE_CONTIG_MASK, req)
>>> +#define RMI_DONATE_STATE(req)        FIELD_GET(RMI_DONATE_STATE_MASK, req)
>>> +
>>
>> As above, RMI_DONATE_{SIZE, COUNT, CONTIG, STATE}_MASK are used for once in this
>> header file. So their definitions can be dropped by modifying the followup macros,
>> as below. Some enhancements are also applicable: (a) Use 'BLOCK' to indicate the
>> unit encoded in the request. (b) The macros are put into order from MSB to LSB.
>>
>> #define RMI_DONATE_STATE(req)        FIELD_GET(GENMASK(18, 17), req)
>> #define RMI_DONATE_CONTIG(req)        FIELD_GET(GENMASK(16, 16), req)
>> #define RMI_DONATE_BLOCK_COUNT(req)    FIELD_GET(GENMASK(15, 2), req)
>> #define RMI_DONATE_BLOCK_SIZE(req)    FIELD_GET(GENMASK(1, 0), req)
> 
> Same as above.
> 

Please rename RMI_DONATE_{SIZE, COUNT} to RMI_DONATE_BLOCK_{SIZE, COUNT} if possible.

>>
>>> +#define RMI_OP_MEM_DELEGATED        0
>>> +#define RMI_OP_MEM_UNDELEGATED        1
>>> +#define RMI_OP_MEM_CONDITIONAL        2
>>> +
>>
>> B4.6.40 RmiOpMemContig type is missed here and they should be used in the c code.
>>
>> #define RMI_OP_MEM_NON_CONTIG    0
>> #define RMI_OP_MEM_CONTIG    1
>>
>> In the c code, we shall have:
>>
>> if (RMI_DONATE_CONTIG(req) == RMI_OP_MEM_CONTIG)) {
>>     ...
>> } else {
>>     ...
>> }
>>
> 
> Does it make much sense though ? I prefer
> 
> if (RMI_DONATE_CONTIG(req))
> 
> to
> 
> 
> if (RMI_DONATE_CONTIG(req) == RMI_OP_MEM_CONTIG)) {
> 
> 
> than having a field for a single bit values. I am happy to change
> this if there is strong preference to the other.
> 

The point is RMM-v2.0-bet3 expose RMI_OP_{MEM, MEM_NON}_CONTIG instead of true/false
to indicate if the requested memory blocks are physically contiguous or not. So the
expression 'if (RMI_DONATE_CONTIG(req) == RMI_OP_MEM_CONTIG)' is consistent to the
RMM-v2.0-bet3 spec.

  
>> Similarly, B4.6.39 RmiOpCanCancel type is missed here and they should be used in
>> the c code.
>>
>> #define RMI_OP_CANNOT_CANCEL    0
>> #define RMI_OP_CAN_CANCEL    1
>>
>> In the c code, we shall have:
>>
>> if (RMI_RETURN_CAN_CANCEL(ret) == RMI_OP_CAN_CANCEL) {
>>      ...
>> } else {
>>      ...
>> }
>>
> 
> Same as above.
> 

Please see above explanation.

>>> +#define RMI_ADDR_TYPE_NONE        0
>>> +#define RMI_ADDR_TYPE_SINGLE        1
>>> +#define RMI_ADDR_TYPE_LIST        2
>>> +
>>> +#define RMI_ADDR_RANGE_SIZE_MASK    GENMASK(1, 0)
>>> +#define RMI_ADDR_RANGE_COUNT_MASK    GENMASK(PAGE_SHIFT - 1, 2)
>>> +#define RMI_ADDR_RANGE_ADDR_MASK    (PAGE_MASK & GENMASK(51, 0))
>>> +#define RMI_ADDR_RANGE_STATE_MASK    GENMASK(63, 62)
>>> +
>>> +#define RMI_ADDR_RANGE_SIZE(ar) (FIELD_GET(RMI_ADDR_RANGE_SIZE_MASK, \
>>> +                           (ar)))
>>> +#define RMI_ADDR_RANGE_COUNT(ar) (FIELD_GET(RMI_ADDR_RANGE_COUNT_MASK, \
>>> +                           (ar)))
>>> +#define RMI_ADDR_RANGE_ADDR(ar)        ((ar) & RMI_ADDR_RANGE_ADDR_MASK)
>>> +#define RMI_ADDR_RANGE_STATE(ar) (FIELD_GET(RMI_ADDR_RANGE_STATE_MASK, \
>>> +                           (ar)))
>>> +
>>
>> I guess it wouldn't a bad idea to explictly indicate 'BLOCK' in the definitions, as
>> below. Some improvements are applicated either: (a) 'ar' is renamed to 'r'; (b) The
>> excessive parentheses are dropped to follow the patterns we already had; (c) For
>> RMI_ADDR_RANGE_ADDR(r), FIELD_GET() is used.
>>
>> #define RMI_ADDR_RANGE_BLOCK_SIZE_MASK        GENMASK(1, 0)
>> #define RMI_ADDR_RANGE_BLOCK_COUNT_MASK        GENMASK(PAGE_SHIFT - 1, 2)
>> #define RMI_ADDR_RANGE_ADDR_MASK        (PAGE_MASK & GENMASK(51, 0))
>> #define RMI_ADDR_RANGE_STATE_MASK        GENMASK(63, 62)
>>
>> #define RMI_ADDR_RANGE_BLOCK_SIZE(r) FIELD_GET(RMI_ADDR_RANGE_SIZE_MASK, r)
>> #define RMI_ADDR_RANGE_BLOCK_COUNT(r) FIELD_GET(RMI_ADDR_RANGE_COUNT_MASK, r)
>> #define RMI_ADDR_RANGE_ADDR(r) FIELD_GET(RMI_ADDR_RANGE_ADDR_MASK, r)
>> #define RMI_ADDR_RANGE_STATE(r) FIELD_GET(RMI_ADDR_RANGE_STATE_MASK, r)
> 
> Ack
> 
>>
>>> +enum rmi_ripas {
>>> +    RMI_EMPTY = 0,
>>> +    RMI_RAM = 1,
>>> +    RMI_DESTROYED = 2,
>>> +    RMI_DEV = 3,
>>> +};
> 
>>> +#define RMI_FEATURE_REGISTER_1_RMI_GRAN_SZ_4KB    BIT(0)
>>> +#define RMI_FEATURE_REGISTER_1_RMI_GRAN_SZ_16KB    BIT(1)
>>> +#define RMI_FEATURE_REGISTER_1_RMI_GRAN_SZ_64KB    BIT(2)
>>> +#define RMI_FEATURE_REGISTER_1_HASH_SHA_256    BIT(3)
>>> +#define RMI_FEATURE_REGISTER_1_HASH_SHA_384    BIT(4)
>>> +#define RMI_FEATURE_REGISTER_1_HASH_SHA_512    BIT(5)
>>> +#define RMI_FEATURE_REGISTER_1_MAX_RECS_ORDER    GENMASK(9, 6)
>>> +#define RMI_FEATURE_REGISTER_1_L0GPTSZ        GENMASK(13, 10)
>>> +#define RMI_FEATURE_REGISTER_1_PPS        GENMASK(16, 14)
>>> +
>>> +#define RMI_FEATURE_REGISTER_2_DA        BIT(0)
>>> +#define RMI_FEATURE_REGISTER_2_DA_COH        BIT(1)
>>> +#define RMI_FEATURE_REGISTER_2_VSMMU        BIT(2)
>>> +#define RMI_FEATURE_REGISTER_2_ATS        BIT(3)
>>> +#define RMI_FEATURE_REGISTER_2_PDEV_MAX_VDEVS_ORDER    GENMASK(7, 4)
>>> +#define RMI_FEATURE_REGISTER_2_VDEV_KROU    BIT(8)
>>> +#define RMI_FEATURE_REGISTER_2_NON_TEE_STREAM    BIT(9)
>>> +#define RMI_FEATURE_REGISTER_2_REALM_MAX_VDEVS_ORDER    GENMASK(14, 10)
>>> +
>>> +#define RMI_FEATURE_REGISTER_3_MAX_NUM_AUX_PLANES    GENMASK(3, 0)
>>> +#define RMI_FEATURE_REGISTER_3_RTT_PLANE        GENMASK(5, 4)
>>> +#define RMI_FEATURE_REGISTER_3_RTT_S2AP_INDIRECT    BIT(6)
>>> +
>>> +#define RMI_FEATURE_REGISTER_4_MEC_COUNT        GENMASK(63, 0)
>>> +
>>
>> We would reorder those feature register definitions from MSB ro LSB :-)
> 
> Ack
> 
> Thanks for your review.
> 
> Cheers
> Suzuki
> 

Thanks,
Gavin