Re: [PATCH v4 05/15] KVM: SEV: publish supported VMSA features

[Paolo Bonzini]

On Tue, Mar 26, 2024 at 1:04 AM Isaku Yamahata <isaku.yamahata@xxxxxxxxx> wrote:
>
> On Mon, Mar 18, 2024 at 07:33:42PM -0400,
> Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>
> > Compute the set of features to be stored in the VMSA when KVM is
> > initialized; move it from there into kvm_sev_info when SEV is initialized,
> > and then into the initial VMSA.
> >
> > The new variable can then be used to return the set of supported features
> > to userspace, via the KVM_GET_DEVICE_ATTR ioctl.
>
> Hi. The current TDX KVM introduces KVM_TDX_CAPABILITIES and struct
> kvm_tdx_capabilities for feature enumeration.  I'm wondering if TDX should also
> use/switch to KVM_GET_DEVICE_ATTR with its own group.  What do you think?
> Something like
>
> #define KVM_DEVICE_ATTR_GROUP_SEV       1
> #define KVM_X86_SEV_VMSA_FEATURES       1
> #define KVM_X86_SEV_xxx                 ...
>
> #define KVM_DEVICE_ATTR_GROUP_TDX       2
> #define KVM_X86_TDX_xxx                 ...

Yes, that's a very good idea. I've added the group argument in v5.

Paolo