Re: [PATCH v1] target/i386: Always set leaf 0x1f

[Xiaoyao Li <xiaoyao.li@intel.com>]

On 8/2/2024 12:46 AM, Manish wrote:
> 
> On 01/08/24 8:41 pm, Xiaoyao Li wrote:
>> !-------------------------------------------------------------------|
>>  CAUTION: External Email
>>
>> |-------------------------------------------------------------------!
>>
>> On 8/1/2024 6:25 PM, Igor Mammedov wrote:
>>> On Thu, 1 Aug 2024 15:36:10 +0530
>>> Manish <manish.mishra@nutanix.com> wrote:
>>>
>>>> On 31/07/24 9:01 pm, Xiaoyao Li wrote:
>>>>> !-------------------------------------------------------------------|
>>>>>   CAUTION: External Email
>>>>>
>>>>> |-------------------------------------------------------------------!
>>>>>
>>>>> On 7/31/2024 4:49 PM, John Levon wrote:
>>>>>> On Wed, Jul 31, 2024 at 03:02:15PM +0800, Xiaoyao Li wrote:
>>>>>>>> Windows does not expect 0x1f to be present for any CPU model. But
>>>>>>>> if it
>>>>>>>> is exposed to the guest, it expects non-zero values.
>>>>>>>
>>>>>>> Please fix Windows!
>>>>>>
>>>>>> A ticket has been filed with MSFT, we are aware this is a guest bug.
>>>>>>
>>>>>> But that doesn't really help anybody trying to use Windows right now.
>>>>>
>>>>> For existing buggy Windows, we can still introduce
>>>>> "cpuid-0x1f-enforce" but not make it default on.
>>>>>
>>>>> People want to boot the buggy Windows needs to opt-in it themselves
>>>>> via "-cpu xxx,cpuid-0x1f-enforce=on". This way, we don't have live
>>>>> migration issue and it doesn't affect anything.
>>>>
>>>>
>>>> Yes, that makes sense, I will send a updated patch by tomorrow if no 
>>>> one
>>>> has any objection with this.
>>>
>>> I'd rename it to
>>>     x-have-cpuid-0x1f-leaf
>>> (x-) to reflect that it's not stable/maintained and subject
>>> to be dropped in future
>>>
>>> Also please clearly spell out that it's a temporary workaround for ...
>>> in commit message.
>>
>> I have a patch at hand, to introduce enable_cpuid_0x1f similar as 
>> enable_cpuid_0xb, for TDX:
>>
>> https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_intel-2Dstaging_qemu-2Dtdx_commit_de08fd30926bc9d7997af6bd12cfff1b998da8b7&d=DwIDaQ&c=s883GpUCOChKOHiocYtGcg&r=c4KON2DiMd-szjwjggQcuUvTsPWblztAL0gVzaHnNmc&m=CIrxjRd0KG4ww4BtSxZysWS0tFYfPGTRBG731EmlUcy7BFlAw3-5PLp2SlKPR83m&s=2gKDZXpqB7wE8v0vtN8l65WBqTtXOUJ-FkMblXcT_Ws&e=
>> It is not a temporary solution. So I would suggest to drop (x-).
>> If no objection, I think Manish can start from my patch and it only 
>> misses a property definition for windows case:
>>
>>   DEFINE_PROP_BOOL("cpuid-0x1f", X86CPU, enable_cpuid_0x1f, false);
>>
>>
> Thanks Xiaoyao, I see your patch does what we require but i am not able 
> to track these patches, are these in line to be merged soon? We need 
> this urgently. Also as it is just a single line change on top of your 
> changes, how i manage my change? Should i wait for you to merge and then 
> send patch or you will be fine to directly include it in your series?

Sent it:

https://lore.kernel.org/qemu-devel/20240802072426.4016194-1-xiaoyao.li@intel.com/

We can continue the discussion from there.

> 
>>
>>>
>>>>
>>>>>> regards
>>>>>> john
>>>>
>>>>
>>>> Thanks
>>>>
>>>> Manish Mishra
>>>>
>>>
>>
> 
> Thanks
> 
> Manish Mishra
>