Re: [Qemu-devel] [PATCH v4 04/29] target-ppc: Copy and split gen_spr_7xx() for 970

[Tom Musta <tommusta@gmail.com>]

On 6/3/2014 4:27 AM, Alexey Kardashevskiy wrote:
> +static void gen_spr_book3s_pmu_user(CPUPPCState *env)
> +{
> +    spr_register(env, SPR_POWER_UMMCR0, "UMMCR0",
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 0x00000000);
> +    spr_register(env, SPR_POWER_UMMCR1, "UMMCR1",
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 0x00000000);
> +    spr_register(env, SPR_POWER_UPMC1, "UPMC1",
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 0x00000000);
> +    spr_register(env, SPR_POWER_UPMC2, "UPMC2",
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 0x00000000);
> +    spr_register(env, SPR_POWER_UPMC3, "UPMC3",
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 0x00000000);
> +    spr_register(env, SPR_POWER_UPMC4, "UPMC4",
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 0x00000000);
> +    spr_register(env, SPR_POWER_USIAR, "USIAR",
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 0x00000000);
> +}

The Uxxxx regs are writeable from supervisor state, aren't they?  (similar comment as UCTRL).

There is also this complicating factor in ISA 2.07 (P8) whereby the PMU Uxxxx SPRs are
readable/writeable based on the state of MMCR0[PMCC] (ick!).

I think either of these can be handled in follow up patches.  I am also not sure that I see a
compelling reason to model the MMCR0[PMCC] accessibility unless we actually start modeling the
PMU (hard).

Reviewed-by: Tom Musta <tommusta@gmail.com>