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AKwUvBw+ByHyA8W+yOJ8fERnb1T+bJ3/s0wgpxBR6MdmLy0BGDbSh1OZrtFCuPWZHQwdd4do0QE=@vger.kernel.org X-Gm-Message-State: AFuF++kWMQvCQW3sgb3iz5XBWTHrT+wgYNzAD2DYzoqZ7tbhHerHfgVy 27f0DSKRX+snteoxQxvUg5/N2c0Zxut6zSZuefdiVZOxy3BWRp/dYPJcTEBiemxkfw/3siIzFZS GhB8WgQ== X-Received: from plmc17.prod.google.com ([2002:a17:903:e91:b0:2dd:95e:8c]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:1a70:b0:2de:834b:b594 with SMTP id d9443c01a7336-2df7dd8dafcmr26948395ad.74.1790267296876; Thu, 24 Sep 2026 09:28:16 -0700 (PDT) Date: Thu, 24 Sep 2026 09:28:15 -0700 In-Reply-To: <3ae12b120c7aa2ca56e46bb9a5b2a7b7fc501131.camel@intel.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <56a61983c03806120e607dfd1e1b7c9046c1f54b.camel@intel.com> <7d40bcd97e01390a345ce1dbe26264e7b064a619.camel@intel.com> <12541025-6579-4baf-911d-dcf1453b3e27@intel.com> <3ae12b120c7aa2ca56e46bb9a5b2a7b7fc501131.camel@intel.com> Message-ID: Subject: Re: TDG quote analysis From: Sean Christopherson To: Rick P Edgecombe Cc: Vishal Annapurve , Yilun Xu , Elena Reshetova , Binbin Wu , Dave Hansen , "kas@kernel.org" , "pbonzini@redhat.com" , Peter Fang , "kvm@vger.kernel.org" Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Thu, Sep 24, 2026, Rick P Edgecombe wrote: > On Wed, 2026-09-23 at 17:18 -0700, Sean Christopherson wrote: > > From an upstream perspective, I think we don't care?=C2=A0 Or rather, w= e *shouldn't* > > have to care beyond letting the admin flip a TDX Module switch.=C2=A0 I= 'm a-ok letting > > end users opt-in to ultra-paranoid mode, with a pile of disclaimers aro= und the > > shortcomings and tradeoffs involved.=C2=A0 I.e. I don't really care how= the quote is > > generated, I just don't want to carry any kernel/KVM code to make it le= ss painful > > (and it should absolutely be opt-in). >=20 > I think the direction is to basically punt on Linux S3M design for the in= itial > upstream implementation. But based on today, I think we would have severa= l > options. This is good thing to do for now I think, because the TDX arch s= ide of > S3M based attestation is still fuzzy. Ya, and what I'm saying is that one of the goals of the TDX Module should b= e to provide a common interface for signing quotes, regardless of what is doing = the actual signing. I.e. beyond flipping a switch at boot time, we shouldn't n= eed to modify the host or guest kernels. Host userspace and maybe guest usersp= ace will need to be aware of which signing implementation is being used, becaus= e it will significantly impact VM scheduling and behavior, but the kernel really shouldn't have to care.