Re: [Qemu-devel] [PULL 12/62] target/ppc/spapr: Enable mitigations by default for pseries-4.0 machine type

[Philippe Mathieu-Daudé]

On 6/28/19 1:54 PM, Laurent Vivier wrote:
> On 28/06/2019 13:27, Philippe Mathieu-Daudé wrote:
>> Hi,
>>
>> On 3/12/19 9:54 AM, David Gibson wrote:
>>> From: Suraj Jitindar Singh <address@hidden>
>>>
>>> There are currently 3 mitigations the availability of which is controlled
>>> by the spapr-caps mechanism, cap-cfpc, cap-sbbc, and cap-ibs. Enable these
>>> mitigations by default for the pseries-4.0 machine type.
>>>
>>> By now machine firmware should have been upgraded to allow these
>>> settings.
>>>
>>> Signed-off-by: Suraj Jitindar Singh <address@hidden>
>>> Message-Id: <address@hidden>
>>> Signed-off-by: David Gibson <address@hidden>
>>> ---
>>>  hw/ppc/spapr.c | 9 ++++++---
>>>  1 file changed, 6 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>>> index 37fd7a1411..946bbcf9ee 100644
>>> --- a/hw/ppc/spapr.c
>>> +++ b/hw/ppc/spapr.c
>>> @@ -4307,9 +4307,9 @@ static void spapr_machine_class_init(ObjectClass *oc, 
>>> void *data)
>>>      smc->default_caps.caps[SPAPR_CAP_HTM] = SPAPR_CAP_OFF;
>>>      smc->default_caps.caps[SPAPR_CAP_VSX] = SPAPR_CAP_ON;
>>>      smc->default_caps.caps[SPAPR_CAP_DFP] = SPAPR_CAP_ON;
>>> -    smc->default_caps.caps[SPAPR_CAP_CFPC] = SPAPR_CAP_BROKEN;
>>> -    smc->default_caps.caps[SPAPR_CAP_SBBC] = SPAPR_CAP_BROKEN;
>>> -    smc->default_caps.caps[SPAPR_CAP_IBS] = SPAPR_CAP_BROKEN;
>>> +    smc->default_caps.caps[SPAPR_CAP_CFPC] = SPAPR_CAP_WORKAROUND;
>>> +    smc->default_caps.caps[SPAPR_CAP_SBBC] = SPAPR_CAP_WORKAROUND;
>>> +    smc->default_caps.caps[SPAPR_CAP_IBS] = SPAPR_CAP_WORKAROUND;
>>>      smc->default_caps.caps[SPAPR_CAP_HPT_MAXPAGESIZE] = 16; /* 64kiB */
>>>      smc->default_caps.caps[SPAPR_CAP_NESTED_KVM_HV] = SPAPR_CAP_OFF;
>>>      smc->default_caps.caps[SPAPR_CAP_LARGE_DECREMENTER] = SPAPR_CAP_ON;
>>> @@ -4389,6 +4389,9 @@ static void 
>>> spapr_machine_3_1_class_options(MachineClass *mc)
>>>      mc->default_cpu_type = POWERPC_CPU_TYPE_NAME("power8_v2.0");
>>>      smc->update_dt_enabled = false;
>>>      smc->dr_phb_enabled = false;
>>> +    smc->default_caps.caps[SPAPR_CAP_CFPC] = SPAPR_CAP_BROKEN;
>>> +    smc->default_caps.caps[SPAPR_CAP_SBBC] = SPAPR_CAP_BROKEN;
>>> +    smc->default_caps.caps[SPAPR_CAP_IBS] = SPAPR_CAP_BROKEN;
>>>      smc->default_caps.caps[SPAPR_CAP_LARGE_DECREMENTER] = SPAPR_CAP_OFF;
>>>  }
>>
> 
> What happens if you start directly qemu with:
> 
>   ... -M cap-cfpc=broken,cap-sbbc=broken,cap-ibs=broken ...
> 
> or with
> 
>   ... -M pseries-3.1.0 ...

Thanks Laurent! Both work.