Re: [Qemu-devel] [PULL 57/60] target/ppc: add HV support for POWER9

[Cédric Le Goater]

On 3/12/19 8:30 PM, Cleber Rosa wrote:
> 
> 
> ----- Original Message -----
>> From: "Cleber Rosa" <address@hidden>
>> To: "Cédric Le Goater" <address@hidden>
>> Cc: "David Gibson" <address@hidden>, "peter maydell" <address@hidden>, 
>> address@hidden,
>> address@hidden, address@hidden, address@hidden
>> Sent: Tuesday, March 12, 2019 3:14:09 PM
>> Subject: Re: [Qemu-devel] [PULL 57/60] target/ppc: add HV support for POWER9
>>
>> On Tue, Mar 12, 2019 at 07:34:04PM +0100, Cédric Le Goater wrote:
>>> On 3/12/19 4:01 PM, Cleber Rosa wrote:
>>>> On Sun, Mar 10, 2019 at 07:27:00PM +1100, David Gibson wrote:
>>>>> From: Cédric Le Goater <address@hidden>
>>>>>
>>>>> We now have enough support to boot a PowerNV machine with a POWER9
>>>>> processor. Allow HV mode on POWER9.
>>>>>
>>>>> Signed-off-by: Cédric Le Goater <address@hidden>
>>>>> Message-Id: <address@hidden>
>>>>> Signed-off-by: David Gibson <address@hidden>
>>>>> ---
>>>>>  target/ppc/translate_init.inc.c | 3 ++-
>>>>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/target/ppc/translate_init.inc.c
>>>>> b/target/ppc/translate_init.inc.c
>>>>> index af70a3b78c..0bd555eb19 100644
>>>>> --- a/target/ppc/translate_init.inc.c
>>>>> +++ b/target/ppc/translate_init.inc.c
>>>>> @@ -8895,7 +8895,7 @@ POWERPC_FAMILY(POWER9)(ObjectClass *oc, void
>>>>> *data)
>>>>>                         PPC_CACHE | PPC_CACHE_ICBI | PPC_CACHE_DCBZ |
>>>>>                         PPC_MEM_SYNC | PPC_MEM_EIEIO |
>>>>>                         PPC_MEM_TLBSYNC |
>>>>> -                       PPC_64B | PPC_64BX | PPC_ALTIVEC |
>>>>> +                       PPC_64B | PPC_64H | PPC_64BX | PPC_ALTIVEC |
>>>>>                         PPC_SEGMENT_64B | PPC_SLBI |
>>>>>                         PPC_POPCNTB | PPC_POPCNTWD |
>>>>>                         PPC_CILDST;
>>>>> @@ -8907,6 +8907,7 @@ POWERPC_FAMILY(POWER9)(ObjectClass *oc, void
>>>>> *data)
>>>>>                          PPC2_ISA205 | PPC2_ISA207S | PPC2_FP_CVT_S64 |
>>>>>                          PPC2_TM | PPC2_ISA300 | PPC2_PRCNTL;
>>>>>      pcc->msr_mask = (1ull << MSR_SF) |
>>>>> +                    (1ull << MSR_SHV) |
>>>>>                      (1ull << MSR_TM) |
>>>>>                      (1ull << MSR_VR) |
>>>>>                      (1ull << MSR_VSX) |
>>>>> --
>>>>> 2.20.1
>>>>>
>>>>>
>>>>
>>>> This change prevents a Fedora 29 kernel[1] from booting... is this
>>>> intended or a known limitation of the Fedora 29 kernel?
>>>
>>> The default CPU is still power8_v2.0. This is curious.
>>>
>>
>> Are you sure?  I'm getting:
>>
>>  $ git rev-parse HEAD
>>  cfc3fef6b4e493bf1a7ee16790ad584e20dfbbd1
>>  $ ./ppc64-softmmu/qemu-system-ppc64 -qmp unix:/tmp/qmp-sock,server
>>  $ ./scripts/qmp/qom-get -s /tmp/qmp-sock /machine/unattached/device[0].type
>>  power9_v2.0-spapr-cpu-core

That's a pseries machine, not a powernv machine. pseries should use P9
processor by default but the patch above should not impact f29 on pseries. 
If it does, then we have a bug. 
 
> Looks like the overall default is "power9_v2.0", and then on pseries-3.1 and
> lower, it's "power8_v2.0", as per 34a6b015a98.

I was looking at pnv_machine_class_init() which sets the default CPU :

    mc->default_cpu_type = POWERPC_CPU_TYPE_NAME("power8_v2.0");

C.

> 
> - Cleber.
> 
>> Thanks,
>> - Cleber.
>>
>>>> FIY, by using a "power8" CPU the Fedora 29 kernel boots successfully.
>>>> For a reproducer, please refer to [2].
>>>
>>>
>>> Thanks,
>>>
>>> C.
>>>
>>>
>>>> Thanks,
>>>> - Cleber.
>>>>
>>>> [1] -
>>>> https://download.fedoraproject.org/pub/fedora-secondary/releases/29/Everything/ppc64le/os/ppc/ppc64/vmlinuz
>>>>
>>>> [2] -
>>>> https://github.com/clebergnu/qemu/blob/sent/target_arch_v4/tests/acceptance/boot_linux_console.py#L138
>>>>
>>>
>>