Re: [RFC PATCH v5 008/104] KVM: TDX: Add a function to initialize TDX module

[Xiaoyao Li]

On 4/2/2022 4:18 AM, Isaku Yamahata wrote:
> On Fri, Apr 01, 2022 at 02:56:40PM +0800,
> Xiaoyao Li <xiaoyao.li@xxxxxxxxx> wrote:
>
> > On 4/1/2022 3:41 AM, Isaku Yamahata wrote:
> > > On Thu, Mar 31, 2022 at 04:31:10PM +1300,
> > > Kai Huang <kai.huang@xxxxxxxxx> wrote:
> > >
> > > > On Fri, 2022-03-04 at 11:48 -0800, isaku.yamahata@xxxxxxxxx wrote:
> > > > > From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> > >
> > > > > Add a wrapper function to initialize the TDX module and get system-wide
> > > > > parameters via those APIs.  Because TDX requires VMX enabled, It will be
> > > > > called on-demand when the first guest TD is created via x86 KVM init_vm
> > > > > callback.
> > > >
> > > > Why not just merge this patch with the change where you implement the init_vm
> > > > callback?  Then you can just declare this patch as "detect and initialize TDX
> > > > module when first VM is created", or something like that..
> > >
> > > Ok. Anyway in the next respoin, tdx module initialization will be done when
> > > loading kvm_intel.ko.  So the whole part will be changed and will be a part
> > > of module loading.
> >
> > Will we change the GET_TDX_CAPABILITIES ioctl back to KVM scope?
>
> No because it system scoped KVM_TDX_CAPABILITIES requires one more callback for
> it.  We can reduce the change.
>
> Or do you have any use case for system scoped KVM_TDX_CAPABILITIES?

No. Just to confirm.

on the other hand, vm-scope IOCTL seems more flexible if different 
capabilities are reported per VM in the future.