linux-kernel - Re: [PATCH v5 0/5] TDX host: kexec() support

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Message-ID: <CAAhR5DEEsFNqdxbd62tGh9Cj7ZQMQs6fEjAKs6djkZzgZALOfw@mail.gmail.com>
Date: Mon, 19 Aug 2024 17:28:12 -0500
From: Sagi Shahar <sagis@...gle.com>
To: "Huang, Kai" <kai.huang@...el.com>
Cc: bp@...en8.de, dave.hansen@...el.com, hpa@...or.com, 
	kirill.shutemov@...ux.intel.com, linux-kernel@...r.kernel.org, 
	luto@...nel.org, mingo@...hat.com, pbonzini@...hat.com, peterz@...radead.org, 
	seanjc@...gle.com, tglx@...utronix.de, thomas.lendacky@....com, 
	x86@...nel.org
Subject: Re: [PATCH v5 0/5] TDX host: kexec() support

On Mon, Aug 19, 2024 at 5:16 PM Huang, Kai <kai.huang@...el.com> wrote:
>
>
>
> On 20/08/2024 9:21 am, Sagi Shahar wrote:
> >> Currently kexec() support and TDX host are muturally exclusive in the
> >> Kconfig.  This series adds the TDX host kexec support so that they can
> >> work together and can be enabled at the same time in the Kconfig.
> >
> > I tried testing the kexec functionality and noticed that the TDX module
> > fails initialization on the second kernel so you can't actually kexec
> > between 2 kernels that enable TDX. Is that the expected behavior? Are
> > there future patches to enable that functionality?
> >
>
> Thanks for testing!
>
> Yes this is the expected behaviour.  If the first kernel has enabled
> TDX, then the second kernel will fail to init TDX.  The reason the first
> SEAMCALL to initialize TDX module in the second kernel will fail due to
> module having been initialized.
>
> However if the first kernel has not enabled TDX, the second kernel is
> able to enable it.

Are there any plans to support both kernels being able to enable TDX
in the future? Either by changes to KVM or the TDX module?