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

[Manish]

On 01/08/24 8:41 pm, Xiaoyao Li wrote:
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> 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:
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> > > > 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?


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

Thanks

Manish Mishra