Re: [Qemu-devel] [PATCH] KVM: emulate lapic tsc deadline timer for hvm

[Liu, Jinsong]

Marcelo Tosatti wrote:
> On Fri, Sep 09, 2011 at 01:12:51AM +0800, Liu, Jinsong wrote:
>>>>> --- a/arch/x86/include/asm/msr-index.h
>>>>> +++ b/arch/x86/include/asm/msr-index.h
>>>>> @@ -229,6 +229,8 @@
>>>>>  #define MSR_IA32_APICBASE_ENABLE (1<<11)
>>>>>  #define MSR_IA32_APICBASE_BASE           (0xfffff<<12)
>>>>> 
>>>>> +#define MSR_IA32_TSCDEADLINE             0x000006e0
>>>>> +
>>>>>  #define MSR_IA32_UCODE_WRITE             0x00000079
>>>>>  #define MSR_IA32_UCODE_REV               0x0000008b
>>>> 
>>>> Need to add to msrs_to_save so live migration works.
>>> 
>>> MSR must be explicitly listed in qemu, also.
>>> 
>> 
>> Marcelo, seems MSR don't need explicitly list in qemu?
>> KVM side adding MSR_IA32_TSCDEADLINE to msrs_to_save is enough. Qemu
>> will get it through KVM_GET_MSR_INDEX_LIST. Do I miss something?
> 
> Notice in target-i386/kvm.c the KVM_GET_MSR_INDEX_LIST list is only
> used for MSR_STAR/MSR_HSAVE_PA presence detection.

Yes

> 
> Do you do need to explicitly add MSR_IA32_TSCDEADLINE to
> kvm_get_msrs/kvm_put_msrs routines.

My question is, which kvm_get_msrs/kvm_put_msrs routine be used by live 
migration, the routine in target-i386/kvm.c, or in kvm/libkvm/libkvm-x86.c? 
They both have ioctl KVM_GET_MSR_INDEX_LIST/ KVM_GET_MSRS/ KVM_SET_MSRS, but 
I'm not clear their purpose/usage difference.

Thanks,
Jinsong