Re: [RFC PATCH v4 03/36] target/i386: Implement mc->kvm_type() to get VM type

[Isaku Yamahata]

On Mon, May 23, 2022 at 10:36:16AM +0200,
Gerd Hoffmann <kraxel@redhat.com> wrote:

>   Hi,
> 
> > +    if (!(kvm_check_extension(KVM_STATE(ms->accelerator), 
> > KVM_CAP_VM_TYPES) & BIT(kvm_type))) {
> > +        error_report("vm-type %s not supported by KVM", 
> > vm_type_name[kvm_type]);
> > +        exit(1);
> > +    }
> 
> Not sure why TDX needs a new vm type whereas sev doesn't.  But that's up
> for debate in the kernel tdx patches, not here.  Assuming the kernel
> interface actually merged will look like this the patch makes sense.

Because VM operations, e.g. KVM_CREATE_VCPU, require TDX specific one in KVM
side, we need to tell this VM is TD.
Also it's for consistency.  It's common pattern to specify vm type with
KVM_CREATE_VM when among other archs.  S390, PPC, MIPS, and ARM64.  Only SEV is
an exception.  It makes default VM into confidential VM after KVM_CREATE_VM.

Thanks,

> 
> Acked-by: Gerd Hoffmann <kraxel@redhat.com>
> 
> take care,
>   Gerd
> 
> 

-- 
Isaku Yamahata <isaku.yamahata@gmail.com>