Re: [PATCH 01/10] xen/arm: ffa: add FF-A v1.2 function IDs

[Bertrand Marquis <Bertrand.Marquis@xxxxxxx>]

Hi Jens,

Thanks a lot for the review.
Please find my answers here after.

> On 1 Dec 2025, at 15:43, Jens Wiklander <jens.wiklander@xxxxxxxxxx> wrote:
> 
> Hi Bertrand,
> 
> On Thu, Nov 27, 2025 at 4:52 PM Bertrand Marquis
> <bertrand.marquis@xxxxxxx> wrote:
>> 
>> Bring the FF-A headers up to the v1.2 baseline and fix the function-number
>> range used for ABI discovery:
>> 
>> - update FFA_FNUM_MAX_VALUE so the FF-A function-number window covers the
>>  full v1.2 range, and derive the ABI bitmap bounds from
>>  FFA_FNUM_MIN_VALUE/FFA_FNUM_MAX_VALUE instead of hard-coding
>>  FFA_ERROR/FFA_MSG_SEND2
>> - define the new v1.2 function IDs; CONSOLE_LOG and
>>  PARTITION_INFO_GET_REGS are added for ABI discovery even though they are
>>  not implemented yet
>> - extend the firmware ABI table to probe RUN and
>>  MSG_SEND_DIRECT_REQ2/RESP2
>> - while there, fix an off-by-one in ffa_fw_supports_fid(): the computed bit
>>  index must be strictly smaller than FFA_ABI_BITMAP_SIZE, so use >= in the
>>  bounds check
>> 
>> Keep FFA_MY_VERSION at 1.1 for now; we only advertise v1.2 once the
>> implementation is fully compliant.
>> 
>> Signed-off-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
>> ---
>> xen/arch/arm/include/asm/tee/ffa.h |  2 +-
>> xen/arch/arm/tee/ffa.c             |  4 ++++
>> xen/arch/arm/tee/ffa_private.h     | 18 +++++++++++-------
>> 3 files changed, 16 insertions(+), 8 deletions(-)
>> 
>> diff --git a/xen/arch/arm/include/asm/tee/ffa.h 
>> b/xen/arch/arm/include/asm/tee/ffa.h
>> index 24cd4d99c8f9..c587f76e63ca 100644
>> --- a/xen/arch/arm/include/asm/tee/ffa.h
>> +++ b/xen/arch/arm/include/asm/tee/ffa.h
>> @@ -16,7 +16,7 @@
>> #include <asm/types.h>
>> 
>> #define FFA_FNUM_MIN_VALUE              _AC(0x60,U)
>> -#define FFA_FNUM_MAX_VALUE              _AC(0x86,U)
>> +#define FFA_FNUM_MAX_VALUE              _AC(0x8F,U)
> 
> This is MAX+1, if I'm not mistaken.

It depends on how we see it:
- FFA v1.2 does not define calls over 8E so in this sense yes
- SMCCC is reserving 0x60 to 0xEF for FF-A so in this sense we are not 
completely
 covering the SMCCC space

I must admit i just used 0x90-1 to cover all 0x60 to 0x90 excluded because i 
did not
wanted to have something to big where we would not use all bits.

So I will keep 0x8F adding a comment saying that SMCCC is reserving
the space until 0xEF but only number up to 0x8E are defined in ffa v1.2
so that FNUM_MAX_VALUE is the first unused value so that I will also
remove the the +1 after.

> 
>> 
>> static inline bool is_ffa_fid(uint32_t fid)
>> {
>> diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c
>> index 1d0239cf6950..2b4e24750d52 100644
>> --- a/xen/arch/arm/tee/ffa.c
>> +++ b/xen/arch/arm/tee/ffa.c
>> @@ -11,6 +11,8 @@
>>  *               https://developer.arm.com/documentation/den0077/a
>>  * FF-A-1.1-REL0: FF-A specification version 1.1 available at
>>  *                https://developer.arm.com/documentation/den0077/e
>> + * FF-A-1.2-REL0: FF-A specification version 1.2 available at
>> + *                https://developer.arm.com/documentation/den0077/j
>>  * TEEC-1.0C: TEE Client API Specification version 1.0c available at
>>  *            
>> https://globalplatform.org/specs-library/tee-client-api-specification/
>>  *
>> @@ -102,6 +104,8 @@ static const struct ffa_fw_abi ffa_fw_abi_needed[] = {
>>     FW_ABI(FFA_MSG_SEND_DIRECT_REQ_32),
>>     FW_ABI(FFA_MSG_SEND_DIRECT_REQ_64),
>>     FW_ABI(FFA_MSG_SEND2),
>> +    FW_ABI(FFA_MSG_SEND_DIRECT_REQ2),
>> +    FW_ABI(FFA_RUN),
>> };
>> 
>> /*
>> diff --git a/xen/arch/arm/tee/ffa_private.h b/xen/arch/arm/tee/ffa_private.h
>> index 6dbdb200d840..d7e6b6f5ef45 100644
>> --- a/xen/arch/arm/tee/ffa_private.h
>> +++ b/xen/arch/arm/tee/ffa_private.h
>> @@ -15,6 +15,7 @@
>> #include <xen/spinlock.h>
>> #include <xen/time.h>
>> #include <xen/types.h>
>> +#include <asm/tee/ffa.h>
>> 
>> /* Error codes */
>> #define FFA_RET_OK                      0
>> @@ -42,6 +43,7 @@
>> 
>> #define FFA_VERSION_1_0         MAKE_FFA_VERSION(1, 0)
>> #define FFA_VERSION_1_1         MAKE_FFA_VERSION(1, 1)
>> +#define FFA_VERSION_1_2         MAKE_FFA_VERSION(1, 2)
>> /* The minimal FF-A version of the SPMC that can be supported */
>> #define FFA_MIN_SPMC_VERSION    FFA_VERSION_1_1
>> 
>> @@ -270,6 +272,10 @@
>> #define FFA_RX_ACQUIRE                  0x84000084U
>> #define FFA_SPM_ID_GET                  0x84000085U
>> #define FFA_MSG_SEND2                   0x84000086U
>> +#define FFA_CONSOLE_LOG                 0x8400008AU
> 
> This is the 32-bit version of the interface. There's also a 64-bit version.

Ack i will add the missing definition for 64bit and rename that one with
a 32 suffix.

> 
>> +#define FFA_PARTITION_INFO_GET_REGS     0x8400008BU
>> +#define FFA_MSG_SEND_DIRECT_REQ2        0xC400008DU
>> +#define FFA_MSG_SEND_DIRECT_RESP2       0xC400008EU
>> 
>> /**
>>  * Encoding of features supported or not by the fw in a bitmap:
>> @@ -280,11 +286,9 @@
>> #define FFA_ABI_ID(id)        ((id) & ARM_SMCCC_FUNC_MASK)
>> #define FFA_ABI_CONV(id)      (((id) >> ARM_SMCCC_CONV_SHIFT) & BIT(0,U))
>> 
>> -#define FFA_ABI_MIN           FFA_ABI_ID(FFA_ERROR)
>> -#define FFA_ABI_MAX           FFA_ABI_ID(FFA_MSG_SEND2)
>> -
>> -#define FFA_ABI_BITMAP_SIZE   (2 * (FFA_ABI_MAX - FFA_ABI_MIN + 1))
>> -#define FFA_ABI_BITNUM(id)    ((FFA_ABI_ID(id) - FFA_ABI_MIN) << 1 | \
>> +#define FFA_ABI_BITMAP_SIZE   (2 * (FFA_FNUM_MAX_VALUE - FFA_FNUM_MIN_VALUE 
>> \
>> +                               + 1))
> 
> Depending on whether FFA_FNUM_MAX_VALUE is MAX+1 or just MAX, we could
> drop the +1.

Agree i will remove the +1 with the change above.

Cheers
Bertrand

> 
> Cheers,
> Jens
> 
>> +#define FFA_ABI_BITNUM(id)    ((FFA_ABI_ID(id) - FFA_FNUM_MIN_VALUE) << 1 | 
>> \
>>                                FFA_ABI_CONV(id))
>> 
>> /* Constituent memory region descriptor */
>> @@ -549,9 +553,9 @@ static inline int32_t ffa_hyp_rx_release(void)
>> 
>> static inline bool ffa_fw_supports_fid(uint32_t fid)
>> {
>> -    BUILD_BUG_ON(FFA_ABI_MIN > FFA_ABI_MAX);
>> +    BUILD_BUG_ON(FFA_FNUM_MIN_VALUE > FFA_FNUM_MAX_VALUE);
>> 
>> -    if ( FFA_ABI_BITNUM(fid) > FFA_ABI_BITMAP_SIZE)
>> +    if ( FFA_ABI_BITNUM(fid) >= FFA_ABI_BITMAP_SIZE)
>>         return false;
>>     return test_bit(FFA_ABI_BITNUM(fid), ffa_fw_abi_supported);
>> }
>> --
>> 2.51.2