Re: [Qemu-devel] [PATCH v2] target-ppc: move POWER7+ to a separate family

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 11/12/2013 06:18 PM, Alexey Kardashevskiy wrote:
> On 11/09/2013 11:20 AM, Alexey Kardashevskiy wrote:
>> On 11/09/2013 03:59 AM, Andreas Färber wrote:
>>> Am 08.11.2013 15:54, schrieb Alexey Kardashevskiy:
>>>> On 11/09/2013 12:44 AM, Andreas Färber wrote:
>>>>> Am 08.11.2013 03:37, schrieb Alexey Kardashevskiy:
>>>>>> So far POWER7+ was a part of POWER7 family. However it has a different
>>>>>> PVR base value so in order to support PVR masks, it needs a separate
>>>>>> family class.
>>>>>>
>>>>>
>>>>> Alexey,
>>>>>
>>>>>> Another reason to make a POWER7+ family is that its name in the device
>>>>>> tree (/proc/device-tree/cpus/cpu*) should be "Power7+" but not "Power7"
>>>>>> and this cannot be easily fixed without a new family class.
>>>>>>
>>>>>> This adds a new family class, PVR base and mask values and moves
>>>>>> Power7+ v2.1 CPU to a new family. The class init function is copied
>>>>>> from the POWER7 family.
>>>>>>
>>>>>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>>>>>> ---
>>>>>> Changes:
>>>>>> v2:
>>>>>> * added VSX enable bit
>>>>>> ---
>>>>>>  target-ppc/cpu-models.c     |  2 +-
>>>>>>  target-ppc/cpu-models.h     |  2 ++
>>>>>>  target-ppc/translate_init.c | 38 ++++++++++++++++++++++++++++++++++++++
>>>>>>  3 files changed, 41 insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/target-ppc/cpu-models.c b/target-ppc/cpu-models.c
>>>>>> index 04d88c5..7c9466f 100644
>>>>>> --- a/target-ppc/cpu-models.c
>>>>>> +++ b/target-ppc/cpu-models.c
>>>>>> @@ -1140,7 +1140,7 @@
>>>>>>                  "POWER7 v2.1")
>>>>>>      POWERPC_DEF("POWER7_v2.3",   CPU_POWERPC_POWER7_v23,             POWER7,
>>>>>>                  "POWER7 v2.3")
>>>>>> -    POWERPC_DEF("POWER7+_v2.1",  CPU_POWERPC_POWER7P_v21,            POWER7,
>>>>>> +    POWERPC_DEF("POWER7+_v2.1",  CPU_POWERPC_POWER7P_v21,            POWER7P,
>>>>>>                  "POWER7+ v2.1")
>>>>>>      POWERPC_DEF("POWER8_v1.0",   CPU_POWERPC_POWER8_v10,             POWER8,
>>>>>>                  "POWER8 v1.0")
>>>>>> diff --git a/target-ppc/cpu-models.h b/target-ppc/cpu-models.h
>>>>>> index 731ec4a..49ba4a4 100644
>>>>>> --- a/target-ppc/cpu-models.h
>>>>>> +++ b/target-ppc/cpu-models.h
>>>>>> @@ -558,6 +558,8 @@ enum {
>>>>>>      CPU_POWERPC_POWER7_v20         = 0x003F0200,
>>>>>>      CPU_POWERPC_POWER7_v21         = 0x003F0201,
>>>>>>      CPU_POWERPC_POWER7_v23         = 0x003F0203,
>>>>>> +    CPU_POWERPC_POWER7P_BASE       = 0x004A0000,
>>>>>> +    CPU_POWERPC_POWER7P_MASK       = 0xFFFF0000,
>>>>>>      CPU_POWERPC_POWER7P_v21        = 0x004A0201,
>>>>>>      CPU_POWERPC_POWER8_BASE        = 0x004B0000,
>>>>>>      CPU_POWERPC_POWER8_MASK        = 0xFFFF0000,
>>>>>> diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
>>>>>> index 35d1389..c030a20 100644
>>>>>> --- a/target-ppc/translate_init.c
>>>>>> +++ b/target-ppc/translate_init.c
>>>>>> @@ -7253,6 +7253,44 @@ POWERPC_FAMILY(POWER7)(ObjectClass *oc, void *data)
>>>>>>      pcc->l1_icache_size = 0x8000;
>>>>>>  }
>>>>>>  
>>>>>> +POWERPC_FAMILY(POWER7P)(ObjectClass *oc, void *data)
>>>>>> +{
>>>>>> +    DeviceClass *dc = DEVICE_CLASS(oc);
>>>>>> +    PowerPCCPUClass *pcc = POWERPC_CPU_CLASS(oc);
>>>>>> +
>>>>>> +    dc->fw_name = "PowerPC,POWER7+";
>>>>>
>>>>> Apart from the commit message differing from the code...
>>>>
>>>>
>>>> In what part?
>>>
>>> The spelling of POWER7. You write it should be "Power7+" but implement
>>> it as upper-case "POWER7+" (ignoring the "PowerPC," prefix, that is).
>>
>>
>> Ah. Sorry.
>>
>>
>>>>> We've had this discussion before: Jacques reported that on his POWER7+
>>>>> box only "POWER7" is shown, not "POWER7+", equivalent to my POWER5+ box
>>>>> showing only "PowerPC,POWER5". Compare my commit, which documents this:
>>>>>
>>>>> http://git.qemu.org/?p=qemu.git;a=commit;h=793826cd460828975591f289de78672af4a47ef9
>>>>>
>>>>> So, adding a POWER7P family seems correct to me, just the fw_name seems
>>>>> wrong - or you'll need to investigate further why there are conflicting
>>>>> reports of how it is shown. Possibly based on revision or pHyp vs. SLOF?
>>>>
>>>>
>>>> Yes we have had this discussion. Paul said it should "POWER7+". The only
>>>> P7+ machine I have handy shows "+":
>>>>
>>>> [aik@vpl4 ~]$ ls -d /proc/device-tree/cpus/PowerPC*
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@0
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@2c
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@10
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@30
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@14
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@34
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@18
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@38
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@1c
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@3c
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@20
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@4
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@24
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@8
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@28
>>>> /proc/device-tree/cpus/PowerPC,POWER7+@c
>>>>
>>>> And this is a host, not a guest. I do not see any good reason to make dt
>>>> names different.
>>>>
>>>> And this does not really matter if there is "+" or not for anybody as far
>>>> as we concerned, ppc64_cpu works either way.
>>>
>>> Right, it may not matter, but I expect you to reference the above commit
>>> id and explain why it should be POWER7+ after all. You failed to come up
>>> with that answer before that patch got applied, so we need to correct
>>> me/it now.
>>>
>>> I have checked with Dinar that under Linux using the Sapphire firmware
>>> "PowerPC,POWER7+@0" does indeed show up in /proc/device-tree/cpus. So
>>> that matches what this patch changes and what you report above.
>>> What could be different in Jacques' setup that he reported it different
>>> from us? He was checking from AIX, is that possibly using a different
>>> firmware, pHyp as for my POWER5+?
>>
>> It must be pHyp, I do not see any other options.
>>
>>> In any case let's please document this properly in the commit message
>>> and not just make contradictory statements about what things should be.
>>
>> I have no idea how to document this. No specification tells what the naming
>> should be so anything I write there is just my assumption.
>>
>> "This defines the cpu node name as PowerPC,POWER7+ to stay in sync with the
>> Sapphire host-side firmware"?
>>
>>
>>> Also, in qemu.git POWER7 does not have the VSX flag, only the
>>> instruction set VSX flag. The addition of this VSX flag for POWER7+ is
>>> not mentioned in the commit message. Does it depend on any of the
>>> lengthy VSX Stage X series on the list or something in ppc-next changing
>>> it for POWER7?
>>
>> The PPC-related patches I post are always made against Alex Graf "ppc-next"
>> tree and his tree contains VSX fixes. Since my patch simply copies POWER7
>> family, I do not see much sense in mentioning all the CPU features it
>> enables for the new family.
>>
>>
>>> Either way, if you or Alex improve on the commit message then you can
>>> add my Reviewed-by, I verified that the VSX flag, desc and fw_name are
>>> the only differences.
> 
> 
> Would this commit message be ok?
> 
> ===
>     target-ppc: move POWER7+ to a separate family
> 
>     So far POWER7+ was a part of POWER7 family. However it has a different
>     PVR base value so in order to support PVR masks, it needs a separate
>     family class.
> 
>     This adds a new family class, PVR base and mask values and moves
>     Power7+ v2.1 CPU to a new family. The class init function is copied
>     from the POWER7 family.
> 
>     This defines a firmware name for the new family as "PowerPC,POWER7+"
>     instead of previously used "PowerPC,POWER7" from the POWER7 family.
>     The reason for that is that the Sapphire firmware (a host firmware)
>     uses "PowerPC,POWER7+" already and since no specification defines
>     exactly the CPU nodes naming in the device tree, we better stay
>     in sync with the host firmware.
> ===


Anyone, ping?




-- 
Alexey