Re: [PATCH v13 016/113] KVM: TDX: x86: Add ioctl to get TDX systemwide parameters

[Isaku Yamahata]

On Wed, Mar 29, 2023 at 04:17:22PM -0700,
Isaku Yamahata <isaku.yamahata@xxxxxxxxx> wrote:

> On Sat, Mar 25, 2023 at 10:43:06AM +0200,
> Zhi Wang <zhi.wang.linux@xxxxxxxxx> wrote:
> 
> > On Sun, 12 Mar 2023 10:55:40 -0700
> > isaku.yamahata@xxxxxxxxx wrote:
> > 
> > Does this have to be a new generic ioctl with a dedicated new x86_ops? SNP
> > does not use it at all and all the system-scoped ioctl of SNP going through
> > the CCP driver. So getting system-scope information of TDX/SNP will end up
> > differently.
> > 
> > Any thought, Sean? Moving getting SNP system-wide information to
> > KVM dev ioctl seems not ideal and TDX does not have a dedicated driver like
> > CCP. Maybe make this ioctl TDX-specific? KVM_TDX_DEV_OP?
> 
> We only need global parameters of the TDX module, and we don't interact with TDX
> module at this point.  One alternative is to export those parameters via sysfs.
> Also the existence of the sysfs node indicates that the TDX module is
> loaded(initialized?) or not in addition to boot log.  Thus we can drop system
> scope one.
> What do you think?
> 
> Regarding to other TDX KVM specific ioctls (KVM_TDX_INIT_VM, KVM_TDX_INIT_VCPU,
> KVM_TDX_INIT_MEM_REGION, and KVM_TDX_FINALIZE_VM), they are specific to KVM.  So
> I don't think it can be split out to independent driver.

Here is the patch to export those info via sysfs.