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

[Igor Mammedov]

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.


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