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From: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu, 4 Apr 2024 13:46:05 +0200
Message-ID: <CABgObfZzkNiP3q8p=KpvvFnh8m6qcHX4=tATaJc7cvVv2QWpJQ@mail.gmail.com>
Subject: Re: [PATCH v4 05/15] KVM: SEV: publish supported VMSA features
To: Isaku Yamahata <isaku.yamahata@intel.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, michael.roth@amd.com, 
	seanjc@google.com, isaku.yamahata@linux.intel.com, rick.p.edgecombe@intel.com, 
	xiaoyao.li@intel.com, kai.huang@intel.com
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On Tue, Mar 26, 2024 at 1:04=E2=80=AFAM Isaku Yamahata <isaku.yamahata@inte=
l.com> wrote:
>
> On Mon, Mar 18, 2024 at 07:33:42PM -0400,
> Paolo Bonzini <pbonzini@redhat.com> 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 initializ=
ed,
> > and then into the initial VMSA.
> >
> > The new variable can then be used to return the set of supported featur=
es
> > 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 shoul=
d 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