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Thu, 05 Nov 2026 07:59:06 -0800 (PST) Received: from [10.245.244.150] ([192.198.151.47]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4b5725fb0d1sm72442095e9.8.2026.11.05.07.59.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Nov 2026 07:59:05 -0800 (PST) Message-ID: <85f899cd277b2188cd4b33f8f21b206fa2ff6f6f.camel@gmail.com> Subject: Re: TDX migration model From: Artem Bityutskiy To: "Serge Hallyn (AMD)" Cc: Peter Xu , Tony Lindgren , Paolo Bonzini , Sean Christopherson , Fabiano Rosas , Jon Grimm , Pankaj Gupta , Tom Lendacky , Marc Zyngier , Oliver Upton , Steven Price , Anup Patel , Samuel Ortiz , Jakub =?UTF-8?Q?R=C5=AF=C5=BEi=C4=8Dka?= , =?ISO-8859-1?Q?J=F6rg_R=F6del?= , Vishal Annapurve , Elena Reshetova , Kai Huang , Kishen Maloor , Mika Westerberg , Peter Fang , Rick Edgecombe , Xiaoyao Li , Xu Yilun , kvm@vger.kernel.org, David.Kaplan@amd.com, Mathias.Brossard@arm.com Date: Thu, 05 Nov 2026 17:59:01 +0200 In-Reply-To: References: <20260831071304.762939-1-tony.lindgren@linux.intel.com> <84bf61e0e810859ed735dc92ab94167727c2e560.camel@gmail.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.60.2 (3.60.2-3.fc44) X-Mailing-List: kvm@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 [I dropped a bunch of people from CC, sorry about that, just restored the C= C list] On Thu, 2026-11-05 at 08:58 -0600, Serge Hallyn (AMD) wrote: > On Wed, Nov 04, 2026 at 03:51:45PM +0200, Artem Bityutskiy wrote: > > Hi Peter, community, > >=20 > > Here is the TDX migration model doc that I mentioned in the CoCo migrat= ion > > uAPI thread: > >=20 > > https://github.com/dedekind/dedekind-share/blob/master/2026/tdx-live-mi= gration.md > >=20 > > The doc focuses on TDX only. It does not cover CoCo in general or > > Linux/KVM.=C2=A0 > >=20 > > The goal is to lay out what the TDX module offers in terms of ABI and > > migration flow today. Hopefully it is easier to read than the TDX specs= , > > which are much more detailed. Feedback is very welcome. > >=20 > > The uAPIs that we suggested were modeled around this flow and ABI. But > > we kept general CoCo VMs in mind as much as we could. > >=20 > > The TDX live migration PoC implementation that we mentioned earlier fol= lows > > the flows and uses the ABIs described in the doc. > >=20 > > Thanks! > >=20 > > P.S. From the ARM talk and hallway conversations at Plumbers, I underst= ood > > that the ARM live migration flow is very similar to TDX. For SNP guests= , we > > have not heard enough yet. > >=20 > > Thanks, > > Artem. >=20 > Thanks, Artem! >=20 > So, looking at the section '### How the Setup Session Works', is it safe > to assume that you are using the qemu migration fd for the message > transfers? So basically qemu loops over KVM_MIGRATE_SETUP calls, which > is directed to platform-specific handlers, which in the tdx case calls > TDH.MIG.SETUP, and this loop continues until TDX_SUCCESS? If so, great, > that mirrors pretty exactly what we were looking at for SNP. Hi, Yes, that's the flow. I=E2=80=99m not sure about the migration fd part, I b= elieve we pass the setup session data via ioctl buffers. I am sure Kishen will can clarify. Thanks, Artem.