Re: [PATCH v3 2/2] target/i386: Add support for save/load IA32_UMWAIT_CONTROL MSR

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

On 6/17/2019 11:39 AM, Xiaoyao Li wrote:
> 
> 
> On 6/16/2019 11:35 PM, Tao Xu wrote:
>> UMWAIT and TPAUSE instructions use IA32_UMWAIT_CONTROL at MSR index
>> E1H to determines the maximum time in TSC-quanta that the processor
>> can reside in either C0.1 or C0.2.
>>
>> This patch is to Add support for save/load IA32_UMWAIT_CONTROL MSR in
>> guest.
>>
>> Co-developed-by: Jingqi Liu <jingqi.liu@intel.com>
>> Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
>> Signed-off-by: Tao Xu <tao3.xu@intel.com>
>> ---
>>
>> no changes in v3:
>> ---
>>   target/i386/cpu.h     |  2 ++
>>   target/i386/kvm.c     | 13 +++++++++++++
>>   target/i386/machine.c | 20 ++++++++++++++++++++
>>   3 files changed, 35 insertions(+)
>>
>> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
>> index 2f7c57a3c2..eb98b2e54a 100644
>> --- a/target/i386/cpu.h
>> +++ b/target/i386/cpu.h
>> @@ -450,6 +450,7 @@ typedef enum X86Seg {
>>   #define MSR_IA32_BNDCFGS                0x00000d90
>>   #define MSR_IA32_XSS                    0x00000da0
>> +#define MSR_IA32_UMWAIT_CONTROL         0xe1
>>   #define XSTATE_FP_BIT                   0
>>   #define XSTATE_SSE_BIT                  1
>> @@ -1348,6 +1349,7 @@ typedef struct CPUX86State {
>>       uint16_t fpregs_format_vmstate;
>>       uint64_t xss;
>> +    uint64_t umwait;
>>       TPRAccess tpr_access_type;
>>   } CPUX86State;
>> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
>> index 3efdb90f11..506c7cd038 100644
>> --- a/target/i386/kvm.c
>> +++ b/target/i386/kvm.c
>> @@ -91,6 +91,7 @@ static bool has_msr_hv_stimer;
>>   static bool has_msr_hv_frequencies;
>>   static bool has_msr_hv_reenlightenment;
>>   static bool has_msr_xss;
>> +static bool has_msr_umwait;
>>   static bool has_msr_spec_ctrl;
>>   static bool has_msr_virt_ssbd;
>>   static bool has_msr_smi_count;
>> @@ -1486,6 +1487,9 @@ static int kvm_get_supported_msrs(KVMState *s)
>>                   case MSR_IA32_XSS:
>>                       has_msr_xss = true;
>>                       break;
>> +                case MSR_IA32_UMWAIT_CONTROL:
>> +                    has_msr_umwait = true;
>> +                    break;
> 
> Need to add MSR_IA32_UMWAIT_CONTROL into msrs_to_save[] in your kvm 
> patches, otherwise qemu never goes into this case.
> 
OK, thank you for your suggestion. I will add it in the next version.