Re: [Qemu-ppc] [PATCH 4/9] target-ppc: Implement "compat" CPU option

[Alexey Kardashevskiy]

On 05/17/2014 06:47 AM, Alexander Graf wrote:
> 
> On 16.05.14 17:17, Alexey Kardashevskiy wrote:
>> On 05/17/2014 12:05 AM, Alexander Graf wrote:
>>> On 15.05.14 13:28, Alexey Kardashevskiy wrote:
>>>> This adds basic support for the "compat" CPU option. By specifying
>>>> the compat property, the user can manually switch guest CPU mode from
>>>> "raw" to "architected".
>>>>
>>>> Since the actual compatibility mode is not implemented yet, this does
>>>> not change the existing behavior.
>>>>
>>>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
>>>> ---
>>>>    hw/ppc/spapr.c              | 15 ++++++++++++++-
>>>>    target-ppc/cpu-models.h     |  6 ++++++
>>>>    target-ppc/cpu-qom.h        |  2 ++
>>>>    target-ppc/cpu.h            |  3 +++
>>>>    target-ppc/translate_init.c | 35 +++++++++++++++++++++++++++++++++++
>>>>    5 files changed, 60 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>>>> index 0f8bd95..61d0675 100644
>>>> --- a/hw/ppc/spapr.c
>>>> +++ b/hw/ppc/spapr.c
>>>> @@ -212,7 +212,8 @@ static int spapr_fixup_cpu_dt(void *fdt,
>>>> sPAPREnvironment *spapr)
>>>>          CPU_FOREACH(cpu) {
>>>>            DeviceClass *dc = DEVICE_GET_CLASS(cpu);
>>>> -        int index = ppc_get_vcpu_dt_id(POWERPC_CPU(cpu));
>>>> +        PowerPCCPU *pcpu = POWERPC_CPU(cpu);
>>>> +        int index = ppc_get_vcpu_dt_id(pcpu);
>>>>            uint32_t associativity[] = {cpu_to_be32(0x5),
>>>>                                        cpu_to_be32(0x0),
>>>>                                        cpu_to_be32(0x0),
>>>> @@ -249,6 +250,14 @@ static int spapr_fixup_cpu_dt(void *fdt,
>>>> sPAPREnvironment *spapr)
>>>>                return ret;
>>>>            }
>>>>    +        if (pcpu->cpu_version) {
>>>> +            ret = fdt_setprop(fdt, offset, "cpu-version",
>>>> +                              &pcpu->cpu_version,
>>>> sizeof(pcpu->cpu_version));
>>>> +            if (ret < 0) {
>>>> +                return ret;
>>>> +            }
>>>> +        }
>>>> +
>>>>            /* Build interrupt servers and gservers properties */
>>>>            for (i = 0; i < smp_threads; i++) {
>>>>                servers_prop[i] = cpu_to_be32(index + i);
>>>> @@ -1278,6 +1287,10 @@ static void ppc_spapr_init(QEMUMachineInitArgs
>>>> *args)
>>>>                kvmppc_set_papr(cpu);
>>>>            }
>>>>    +        if (cpu->max_compat) {
>>>> +            ppc_set_compat(cpu, cpu->max_compat);
>>>> +        }
>>>> +
>>>>            xics_cpu_setup(spapr->icp, cpu);
>>>>              qemu_register_reset(spapr_cpu_reset, cpu);
>>>> diff --git a/target-ppc/cpu-models.h b/target-ppc/cpu-models.h
>>>> index 33d2c51..45c0028 100644
>>>> --- a/target-ppc/cpu-models.h
>>>> +++ b/target-ppc/cpu-models.h
>>>> @@ -753,4 +753,10 @@ enum {
>>>>        POWERPC_SVR_8641D              = 0x80900121,
>>>>    };
>>>>    +/* Processor Compatibility mask (PCR) */
>>>> +enum {
>>>> +    POWERPC_ISA_COMPAT_2_05 = 0x02,
>>>> +    POWERPC_ISA_COMPAT_2_06 = 0x04,
>>>> +};
>>>> +
>>>>    #endif
>>>> diff --git a/target-ppc/cpu-qom.h b/target-ppc/cpu-qom.h
>>>> index 2a8515b..dfd1419 100644
>>>> --- a/target-ppc/cpu-qom.h
>>>> +++ b/target-ppc/cpu-qom.h
>>>> @@ -83,6 +83,7 @@ typedef struct PowerPCCPUClass {
>>>>     * @env: #CPUPPCState
>>>>     * @cpu_dt_id: CPU index used in the device tree. KVM uses this
>>>> index too
>>>>     * @max_compat: Maximal supported logical PVR from the command line
>>>> + * @cpu_version: Current logical PVR, zero if in "raw" mode
>>>>     *
>>>>     * A PowerPC CPU.
>>>>     */
>>>> @@ -94,6 +95,7 @@ struct PowerPCCPU {
>>>>        CPUPPCState env;
>>>>        int cpu_dt_id;
>>>>        uint32_t max_compat;
>>>> +    uint32_t cpu_version;
>>>>    };
>>>>      static inline PowerPCCPU *ppc_env_get_cpu(CPUPPCState *env)
>>>> diff --git a/target-ppc/cpu.h b/target-ppc/cpu.h
>>>> index d498340..f61675a 100644
>>>> --- a/target-ppc/cpu.h
>>>> +++ b/target-ppc/cpu.h
>>>> @@ -1123,6 +1123,8 @@ void ppc_store_msr (CPUPPCState *env, target_ulong
>>>> value);
>>>>      void ppc_cpu_list (FILE *f, fprintf_function cpu_fprintf);
>>>>    +void ppc_set_compat(PowerPCCPU *cpu, uint32_t cpu_version);
>>>> +
>>>>    /* Time-base and decrementer management */
>>>>    #ifndef NO_CPU_IO_DEFS
>>>>    uint64_t cpu_ppc_load_tbl (CPUPPCState *env);
>>>> @@ -1338,6 +1340,7 @@ static inline int cpu_mmu_index (CPUPPCState *env)
>>>>    #define SPR_LPCR              (0x13E)
>>>>    #define SPR_BOOKE_DVC2        (0x13F)
>>>>    #define SPR_BOOKE_TSR         (0x150)
>>>> +#define SPR_PCR               (0x152)
>>>>    #define SPR_BOOKE_TCR         (0x154)
>>>>    #define SPR_BOOKE_TLB0PS      (0x158)
>>>>    #define SPR_BOOKE_TLB1PS      (0x159)
>>>> diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
>>>> index 6f61b34..c4bd5de 100644
>>>> --- a/target-ppc/translate_init.c
>>>> +++ b/target-ppc/translate_init.c
>>>> @@ -7803,6 +7803,15 @@ static void init_proc_POWER7 (CPUPPCState *env)
>>>>        /* Can't find information on what this should be on reset.  This
>>>>         * value is the one used by 74xx processors. */
>>>>        vscr_init(env, 0x00010000);
>>>> +
>>>> +    /*
>>>> +     * Register PCR to report POWERPC_EXCP_PRIV_REG instead of
>>>> +     * POWERPC_EXCP_INVAL_SPR.
>>>> +     */
>>>> +    spr_register(env, SPR_PCR, "PCR",
>>>> +                 SPR_NOACCESS, SPR_NOACCESS,
>>>> +                 SPR_NOACCESS, SPR_NOACCESS,
>>>> +                 0x00000000);
>>>>    }
>>>>      POWERPC_FAMILY(POWER7)(ObjectClass *oc, void *data)
>>>> @@ -8880,6 +8889,32 @@ static void ppc_cpu_unrealizefn(DeviceState *dev,
>>>> Error **errp)
>>>>        }
>>>>    }
>>>>    +void ppc_set_compat(PowerPCCPU *cpu, uint32_t cpu_version)
>>>> +{
>>>> +    CPUPPCState *env = &cpu->env;
>>>> +
>>>> +    cpu->cpu_version = cpu_version;
>>>> +
>>>> +    /*
>>>> +     * Calculate PCR value from virtual PVR.
>>>> +     * TODO: support actual compatibility in TCG.
>>>> +     */
>>>> +    switch (cpu_version) {
>>>> +    case CPU_POWERPC_LOGICAL_2_05:
>>>> +        env->spr[SPR_PCR] = POWERPC_ISA_COMPAT_2_05;
>>>> +        break;
>>>> +    case CPU_POWERPC_LOGICAL_2_06:
>>>> +        env->spr[SPR_PCR] = POWERPC_ISA_COMPAT_2_06;
>>>> +        break;
>>>> +    case CPU_POWERPC_LOGICAL_2_06_PLUS:
>>>> +        env->spr[SPR_PCR] = POWERPC_ISA_COMPAT_2_06;
>>>> +        break;
>>> Don't we have to disable all those fancy p8 features too?
>>>
>>> #define   PCR_VEC_DIS   (1ul << (63-0)) /* Vec. disable (bit NA since
>>> POWER8) */
>>> #define   PCR_VSX_DIS   (1ul << (63-1)) /* VSX disable (bit NA since
>>> POWER8) */
>>> #define   PCR_TM_DIS    (1ul << (63-2)) /* Trans. memory disable
>>> (POWER8) */
>> Yep, makes sense to set "TM" for POWER < 8 and VSX+VEC for POWER < 7.
>>
>>> In fact, we probably want those bits always set when compat < power8.
>> Why? VSX is present on power7. VEC is defined in 2.06 too.
> 
> True. So how does pre-p8 treat those p8 and above bits?

PowerISA 2.07 says if 2.06 mode is selected, the TM bit does not matter
anymore - TM will be disabled because 2.06 does not define it at all. The
same is true for VSX and 2.05 mode. So just setting a mode must be ok.



-- 
Alexey