Re: [Qemu-devel] [PATCH v3 05/17] target-i386: Add x86_set_hyperv.

[Don Slutz <Don@CloudSwitch.com>]

On 09/19/12 15:32, Eduardo Habkost wrote:
> On Mon, Sep 17, 2012 at 10:00:55AM -0400, Don Slutz wrote:
>> This is used to set the cpu object's hypervisor level to the default for Microsoft's Hypervisor.
>>
>> Signed-off-by: Don Slutz <Don@CloudSwitch.com>
>> ---
>>   target-i386/cpu.c |   10 ++++++++++
>>   1 files changed, 10 insertions(+), 0 deletions(-)
>>
>> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
>> index 0e4a18d..4120393 100644
>> --- a/target-i386/cpu.c
>> +++ b/target-i386/cpu.c
>> @@ -1192,6 +1192,13 @@ static void x86_cpuid_set_hv_level(Object *obj, Visitor *v, void *opaque,
>>   }
>>
>>   #if !defined(CONFIG_USER_ONLY)
>> +static void x86_set_hyperv(Object *obj, Error **errp)
>> +{
>> +    X86CPU *cpu = X86_CPU(obj);
>> +
>> +    cpu->env.cpuid_hv_level = HYPERV_CPUID_MIN;
> HYPERV_CPUID_MIN is defined on linux-headers/asm-x86/hyperv.h, that is
> included only if build host is linux-x86 and CONFIG_KVM is set.
>
Will fix.  I see 3 options:

1) Use the numbers like 0x40000005

2) Use QEMU defines like:
      #define CPUID_HV_LEVEL_HYPERV  0x40000005

3) Use condtional define:
      #ifndef HYPERV_CPUID_MIN
      #define CPUID_HV_LEVEL_HYPERV  0x40000005
      #else
      #define CPUID_HV_LEVEL_HYPERV  HYPERV_CPUID_MIN
      #endif

I lean to #2 of #3 and both over #1.  This is because if in the future 
if HYPERV_CPUID_MIN ever changes then a patch to QEMU needs to be done 
and considered before that change can be seen by a guest.  Note: since 
hypervisor-level=0x40000006 can be specified, this might be enough to do 
some testing.

Please advise.

>> +}
>> +
>>   static void x86_get_hv_spinlocks(Object *obj, Visitor *v, void *opaque,
>>                                    const char *name, Error **errp)
>>   {
>> @@ -1214,6 +1221,7 @@ static void x86_set_hv_spinlocks(Object *obj, Visitor *v, void *opaque,
>>           return;
>>       }
>>       hyperv_set_spinlock_retries(value);
>> +    x86_set_hyperv(obj, errp);
>>   }
>>
>>   static void x86_get_hv_relaxed(Object *obj, Visitor *v, void *opaque,
>> @@ -1234,6 +1242,7 @@ static void x86_set_hv_relaxed(Object *obj, Visitor *v, void *opaque,
>>           return;
>>       }
>>       hyperv_enable_relaxed_timing(value);
>> +    x86_set_hyperv(obj, errp);
>>   }
>>
>>   static void x86_get_hv_vapic(Object *obj, Visitor *v, void *opaque,
>> @@ -1254,6 +1263,7 @@ static void x86_set_hv_vapic(Object *obj, Visitor *v, void *opaque,
>>           return;
>>       }
>>       hyperv_enable_vapic_recommended(value);
>> +    x86_set_hyperv(obj, errp);
>>   }
>>   #endif
>>
>> --
>> 1.7.1
>>
>>
    -Don Slutz