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Message-ID: <9b90aaac2d55674550d35ce5a4ddd604825423c3.camel@intel.com>
Subject: Re: [RFC PATCH v5 010/104] KVM: TDX: Make TDX VM type supported
From:   Kai Huang <kai.huang@intel.com>
To:     Isaku Yamahata <isaku.yamahata@gmail.com>
Cc:     isaku.yamahata@intel.com, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
        Jim Mattson <jmattson@google.com>, erdemaktas@google.com,
        Connor Kuehl <ckuehl@redhat.com>,
        Sean Christopherson <seanjc@google.com>
Date:   Wed, 16 Mar 2022 10:47:31 +1300
In-Reply-To: <20220315210350.GE1964605@ls.amr.corp.intel.com>
References: <cover.1646422845.git.isaku.yamahata@intel.com>
         <0596db2913da40660e87d5005167c623cee14765.1646422845.git.isaku.yamahata@intel.com>
         <18a150fd2e0316b4bae283d244f856494e0dfefd.camel@intel.com>
         <20220315210350.GE1964605@ls.amr.corp.intel.com>
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On Tue, 2022-03-15 at 14:03 -0700, Isaku Yamahata wrote:
> On Mon, Mar 14, 2022 at 12:08:59PM +1300,
> Kai Huang <kai.huang@intel.com> wrote:
> 
> > On Fri, 2022-03-04 at 11:48 -0800, isaku.yamahata@intel.com wrote:
> > > From: Isaku Yamahata <isaku.yamahata@intel.com>
> > > 
> > > As first step TDX VM support, return that TDX VM type supported to device
> > > model, e.g. qemu.  The callback to create guest TD is vm_init callback for
> > > KVM_CREATE_VM.  Add a place holder function and call a function to
> > > initialize TDX module on demand because in that callback VMX is enabled by
> > > hardware_enable callback (vmx_hardware_enable).
> > 
> > Should we put this patch at the end of series until all changes required to run
> > TD are introduced?  This patch essentially tells userspace KVM is ready to
> > support a TD but actually it's not ready.  And this might also cause bisect
> > issue I suppose?
> 
> The intention is that developers can exercise the new code step-by-step even if
> the TDX KVM isn't complete.

What is the purpose/value to allow developers to exercise the new code step-by-
step?  Userspace cannot create TD successfully anyway until all patches are
ready.

-- 
Thanks,
-Kai