Re: [PATCH v2 3/3] ppc: Enable 2nd DAWR support on p10

[David Gibson]

On Mon, Mar 29, 2021 at 07:04:24PM +0530, Ravi Bangoria wrote:
> Hi David,
> 
> > > @@ -241,6 +241,31 @@ static void spapr_dt_pa_features(SpaprMachineState 
> > > *spapr,
> > >           /* 60: NM atomic, 62: RNG */
> > >           0x80, 0x00, 0x80, 0x00, 0x00, 0x00, /* 60 - 65 */
> > >       };
> > > +    uint8_t pa_features_310[] = { 66, 0,
> > > +        /* 0: MMU|FPU|SLB|RUN|DABR|NX, 1: 
> > > fri[nzpm]|DABRX|SPRG3|SLB0|PP110 */
> > > +        /* 2: VPM|DS205|PPR|DS202|DS206, 3: LSD|URG, SSO, 5: 
> > > LE|CFAR|EB|LSQ */
> > > +        0xf6, 0x1f, 0xc7, 0xc0, 0x80, 0xf0, /* 0 - 5 */
> > > +        /* 6: DS207 */
> > > +        0x80, 0x00, 0x00, 0x00, 0x00, 0x00, /* 6 - 11 */
> > > +        /* 16: Vector */
> > > +        0x00, 0x00, 0x00, 0x00, 0x80, 0x00, /* 12 - 17 */
> > > +        /* 18: Vec. Scalar, 20: Vec. XOR, 22: HTM */
> > > +        0x80, 0x00, 0x80, 0x00, 0x00, 0x00, /* 18 - 23 */
> > > +        /* 24: Ext. Dec, 26: 64 bit ftrs, 28: PM ftrs */
> > > +        0x80, 0x00, 0x80, 0x00, 0x80, 0x00, /* 24 - 29 */
> > > +        /* 30: MMR, 32: LE atomic, 34: EBB + ext EBB */
> > > +        0x80, 0x00, 0x80, 0x00, 0xC0, 0x00, /* 30 - 35 */
> > > +        /* 36: SPR SO, 38: Copy/Paste, 40: Radix MMU */
> > > +        0x80, 0x00, 0x80, 0x00, 0x80, 0x00, /* 36 - 41 */
> > > +        /* 42: PM, 44: PC RA, 46: SC vec'd */
> > > +        0x80, 0x00, 0x80, 0x00, 0x80, 0x00, /* 42 - 47 */
> > > +        /* 48: SIMD, 50: QP BFP, 52: String */
> > > +        0x80, 0x00, 0x80, 0x00, 0x80, 0x00, /* 48 - 53 */
> > > +        /* 54: DecFP, 56: DecI, 58: SHA */
> > > +        0x80, 0x00, 0x80, 0x00, 0x80, 0x00, /* 54 - 59 */
> > > +        /* 60: NM atomic, 62: RNG, 64: DAWR1 */
> > > +        0x80, 0x00, 0x80, 0x00, 0x00, 0x00, /* 60 - 65 */
> > > +    };
> > 
> > I don't see any point adding pa_features_310: it's identical to
> > pa_features_300, AFAICT.
> 
> Sure. The only difference is in the comment part: /* ... 64: DAWR1  */
> I'll update pa_features_300 with something like:
> 
>         /* ... 64: DAWR1 (ISA 3.1) */
> 
> and reuse pa_features_300.
> 
> [...]
> 
> > > +static void cap_dawr1_apply(SpaprMachineState *spapr, uint8_t val,
> > > +                               Error **errp)
> > > +{
> > > +    if (!val) {
> > > +        return; /* Disable by default */
> > > +    }
> > > +
> > > +    if (tcg_enabled()) {
> > > +        error_setg(errp,
> > > +                "DAWR1 not supported in TCG. Try appending -machine 
> > > cap-dawr1=off");
> > 
> > I don't love this.  Is anyone working on DAWR1 emulation for POWER10?
> 
> No. Infact DAWR0 is also not enabled in TCG mode.

Huh.  Good point.

> 
> [...]
> 
> > >   static void gen_spr_970_dbg(CPUPPCState *env)
> > >   {
> > >       /* Breakpoints */
> > > @@ -8727,7 +8742,7 @@ static void init_proc_POWER8(CPUPPCState *env)
> > >       /* Common Registers */
> > >       init_proc_book3s_common(env);
> > >       gen_spr_sdr1(env);
> > > -    gen_spr_book3s_207_dbg(env);
> > > +    gen_spr_book3s_310_dbg(env);
> > 
> > This should surely be in init_proc_POWER10, not init_proc_POWER8.
> 
> Sure.
> 
> Thanks for the review,
> Ravi
> 

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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