Re: [Qemu-devel] [PATCH v4 22/29] target-ppc: Add POWER8's MMCR2/MMCRS SPRs

[Alexey Kardashevskiy]

On 06/04/2014 03:10 AM, Tom Musta wrote:
> On 6/3/2014 4:27 AM, Alexey Kardashevskiy wrote:
>> This adds POWER8 specific PMU MMCR2/MMCRS SPRs.
>>
>> This adds a spr_write_ureg helper for changing a hypv-privileged SPR when
>> it is accessed via its user-privileged mirror. A spr_read_ureg() is
>> already there. Since the new helper is only used by book3s CPUs, it is
>> limited to TARGET_PPC64 to make gcc happy when QEMU is compiled for 32 bit.
>>
>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
>> ---
>> Changes:
>> v4:
>> * disabled write_ureg for user mode, privileged mode is still needed for
>> recent guest kernels to boot on POWER8
>> ---
>>  target-ppc/cpu.h            |  3 +++
>>  target-ppc/translate_init.c | 29 +++++++++++++++++++++++++++++
>>  2 files changed, 32 insertions(+)
>>
>> diff --git a/target-ppc/cpu.h b/target-ppc/cpu.h
>> index 32fadcd..cf1ccad 100644
>> --- a/target-ppc/cpu.h
>> +++ b/target-ppc/cpu.h
>> @@ -1480,6 +1480,7 @@ static inline int cpu_mmu_index (CPUPPCState *env)
>>  #define SPR_MPC_MI_CTR        (0x300)
>>  #define SPR_PERF1             (0x301)
>>  #define SPR_RCPU_MI_RBA1      (0x301)
>> +#define SPR_POWER_UMMCR2      (0x301)
>>  #define SPR_PERF2             (0x302)
>>  #define SPR_RCPU_MI_RBA2      (0x302)
>>  #define SPR_MPC_MI_AP         (0x302)
>> @@ -1527,6 +1528,7 @@ static inline int cpu_mmu_index (CPUPPCState *env)
>>  #define SPR_MPC_MD_TW         (0x30F)
>>  #define SPR_UPERF0            (0x310)
>>  #define SPR_UPERF1            (0x311)
>> +#define SPR_POWER_MMCR2       (0x311)
>>  #define SPR_UPERF2            (0x312)
>>  #define SPR_POWER_MMCRA       (0X312)
>>  #define SPR_UPERF3            (0x313)
>> @@ -1579,6 +1581,7 @@ static inline int cpu_mmu_index (CPUPPCState *env)
>>  #define SPR_440_ITV3          (0x377)
>>  #define SPR_440_CCR1          (0x378)
>>  #define SPR_DCRIPR            (0x37B)
>> +#define SPR_POWER_MMCRS       (0x37E)
>>  #define SPR_PPR               (0x380)
>>  #define SPR_750_GQR0          (0x390)
>>  #define SPR_440_DNV0          (0x390)
>> diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
>> index 9b83d56..6bb0788 100644
>> --- a/target-ppc/translate_init.c
>> +++ b/target-ppc/translate_init.c
>> @@ -175,6 +175,13 @@ static void spr_read_ureg (void *opaque, int gprn, int 
>> sprn)
>>      gen_load_spr(cpu_gpr[gprn], sprn + 0x10);
>>  }
>>  
>> +#if defined(TARGET_PPC64) && !defined(CONFIG_USER_ONLY)
>> +static void spr_write_ureg(void *opaque, int sprn, int gprn)
>> +{
>> +    gen_store_spr(sprn + 0x10, cpu_gpr[gprn]);
>> +}
>> +#endif
>> +
>>  /* SPR common to all non-embedded PowerPC */
>>  /* DECR */
>>  #if !defined(CONFIG_USER_ONLY)
>> @@ -7500,6 +7507,26 @@ static void gen_spr_970_pmu_user(CPUPPCState *env)
>>                   0x00000000);
>>  }
>>  
>> +static void gen_spr_power8_pmu_hypv(CPUPPCState *env)
>> +{
>> +    spr_register_kvm(env, SPR_POWER_MMCR2, "MMCR2",
>> +                     SPR_NOACCESS, SPR_NOACCESS,
>> +                     &spr_read_generic, &spr_write_generic,
>> +                     KVM_REG_PPC_MMCR2, 0x00000000);
>> +    spr_register_kvm(env, SPR_POWER_MMCRS, "MMCRS",
>> +                     SPR_NOACCESS, SPR_NOACCESS,
>> +                     &spr_read_generic, &spr_write_generic,
>> +                     KVM_REG_PPC_MMCRS, 0x00000000);
>> +}
> 
> 
> Supervisor.
> 
>> +
>> +static void gen_spr_power8_pmu_user(CPUPPCState *env)
>> +{
>> +    spr_register(env, SPR_POWER_UMMCR2, "UMMCR2",
>> +                 &spr_read_ureg, SPR_NOACCESS,
>> +                 &spr_read_ureg, &spr_write_ureg,
>> +                 0x00000000);
>> +}
>> +
> 
> The write_ureg should probably also be applied to the other PMU Uxxxx SPRs, 
> no?


We do not support EBB and without that there should be no write_ureg at
all. Your comment in patch #4 is about that, right? But UMMCR2 is still
accessed by fresh guests, this is the only reason why I enabled this one.

So what does make sense to do with all of them?


> 
>>  static void gen_spr_power5p_ear(CPUPPCState *env)
>>  {
>>      /* External access control */
>> @@ -7656,6 +7683,8 @@ static void init_proc_book3s_64(CPUPPCState *env, int 
>> version)
>>      if (version >= BOOK3S_CPU_POWER8) {
>>          gen_spr_power8_tce_address_control(env);
>>          gen_spr_power8_fscr(env);
>> +        gen_spr_power8_pmu_hypv(env);
>> +        gen_spr_power8_pmu_user(env);
>>      }
>>  #if !defined(CONFIG_USER_ONLY)
>>      switch (version) {
>>
> 
> Reviewed-by: Tom Musta <address@hidden>
> 


-- 
Alexey