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

[Laurent Vivier <lvivier@redhat.com>]

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 <sjitindarsingh@gmail.com>
>>
>> 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 <sjitindarsingh@gmail.com>
>> Message-Id: <20190301044609.9626-3-sjitindarsingh@gmail.com>
>> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
>> ---
>>  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