Re: [RFC PATCH v2 02/15] s390x/cpumodel: add msa11 subfunctions

[Hendrik Brueckner <brueckner@linux.ibm.com>]

On Mon, Dec 09, 2024 at 04:04:19PM +0100, Janosch Frank wrote:
> On 12/6/24 1:27 PM, Hendrik Brueckner wrote:
> > MSA11 introduces new HMAC subfunctions.
> > 
> > Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
> > Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
> > ---
> >   target/s390x/cpu_features.c         |  2 ++
> >   target/s390x/cpu_features_def.h.inc | 10 ++++++++++
> >   target/s390x/cpu_models.c           |  8 ++++++++
> >   target/s390x/gen-features.c         | 24 ++++++++++++++++++++++++
> >   4 files changed, 44 insertions(+)
> [...]
> >   /* Features exposed via the KMC instruction. */
> >   DEF_FEAT(KMC_DEA, "kmc-dea", KMC, 1, "KMC DEA")
> > @@ -275,6 +283,8 @@ DEF_FEAT(PCKMO_ECC_P384, "pckmo-ecc-p384", PCKMO, 33, "PCKMO Encrypt-ECC-P384-Ke
> >   DEF_FEAT(PCKMO_ECC_P521, "pckmo-ecc-p521", PCKMO, 34, "PCKMO Encrypt-ECC-P521-Key")
> >   DEF_FEAT(PCKMO_ECC_ED25519, "pckmo-ecc-ed25519", PCKMO, 40 , "PCKMO Encrypt-ECC-Ed25519-Key")
> >   DEF_FEAT(PCKMO_ECC_ED448, "pckmo-ecc-ed448", PCKMO, 41 , "PCKMO Encrypt-ECC-Ed448-Key")
> > +DEF_FEAT(PCKMO_HMAC_512, "pckmo-hmac-512", PCKMO, 118, "PCKMO Encrypt-HMAC-512-Key")
> > +DEF_FEAT(PCKMO_HMAC_1024, "pckmo-hmac-1024", PCKMO, 122, "PCKMO Encrypt-HMAC-1024-Key")
> 
> It seems like we never did MSAx prereq checks for PCKMO like we do for the
> other instructions. Don't we need to check for MSA3 for these features too?
> 
> I see no code that puts EXT_11 and EXT_11_PCKMO in a group where we could
> piggyback on the EXT_11 check for MSA3. What am I missing?

Similar to my other comment. EXT_11 does not have an STFLE bit and, hence,
no feature definition. That's why each introduced subfunc requires MSA3
(for which there is STFLE bit).

The check_consistencies functions works on feature definitions, not on the
feature group definitions.

Hope this helps.