Re: [PATCH] target/i386: Remove monitor from some CPU model

[Tao Xu <tao3.xu@intel.com>]

On 11/19/2019 6:10 AM, Eduardo Habkost wrote:
> On Fri, Nov 15, 2019 at 04:33:45PM +0800, Tao Xu wrote:
>> Add new version of Snowridge, Denverton, Opteron_G3, EPYC, and Dhyana
>> CPU model to remove MONITOR/MWAIT feature.
>>
>> After QEMU/KVM use "-overcommit cpu-pm=on" to expose MONITOR/MWAIT
>> (commit id 6f131f13e68d648a8e4f083c667ab1acd88ce4cd), the MONITOR/MWAIT
>> feature in these CPU model is unused.
>>
>> Signed-off-by: Tao Xu <tao3.xu@intel.com>
>> ---
>>   target/i386/cpu.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 58 insertions(+)
>>
>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>> index a624163ac2..7c5f1e8fe0 100644
>> --- a/target/i386/cpu.c
>> +++ b/target/i386/cpu.c
>> @@ -2770,6 +2770,19 @@ static X86CPUDefinition builtin_x86_defs[] = {
>>               MSR_ARCH_CAP_RDCL_NO | MSR_ARCH_CAP_SKIP_L1DFL_VMENTRY,
>>           .xlevel = 0x80000008,
>>           .model_id = "Intel Atom Processor (Denverton)",
>> +        .versions = (X86CPUVersionDefinition[]) {
>> +            { .version = 1 },
>> +            {
>> +                .version = 2,
>> +                .props = (PropValue[]) {
>> +                    { "monitor", "off" },
>> +                    { "model-id",
>> +                      "Intel Atom Processor (Denverton, no MONITOR)" },
> 
> We never changed model-id when adding/removing features in
> machine-type code, and I don't see why we should start doing that
> now.  This info might be helpful on "-cpu help", but probably
> confusing for people looking at /proc/cpuinfo inside the VM.
> 
> If you think it is important to add extra info to "-cpu help", I
> suggest you send a patch adding a separate field instead of
> changing model ID on CPUID.
> 

OK I will add a new info to do this.