linux-kernel - Re: [PATCHv6 00/16] x86/tdx: Add kexec support

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Message-ID: <CABgObfZiyx8hRsD37xZq5TNs9sRq48vLUxbOKa=HZ1vcr67sWQ@mail.gmail.com>
Date: Tue, 30 Jan 2024 15:59:34 +0100
From: Paolo Bonzini <pbonzini@...hat.com>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, 
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org, 
	"Rafael J. Wysocki" <rafael@...nel.org>, Peter Zijlstra <peterz@...radead.org>, 
	Adrian Hunter <adrian.hunter@...el.com>, 
	Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>, 
	Elena Reshetova <elena.reshetova@...el.com>, Jun Nakajima <jun.nakajima@...el.com>, 
	Rick Edgecombe <rick.p.edgecombe@...el.com>, Tom Lendacky <thomas.lendacky@....com>, 
	"Kalra, Ashish" <ashish.kalra@....com>, Sean Christopherson <seanjc@...gle.com>, 
	"Huang, Kai" <kai.huang@...el.com>, Baoquan He <bhe@...hat.com>, kexec@...ts.infradead.org, 
	linux-coco@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv6 00/16] x86/tdx: Add kexec support

On Tue, Jan 30, 2024 at 3:34 PM Kirill A. Shutemov
<kirill.shutemov@...ux.intel.com> wrote:
>
> On Tue, Jan 30, 2024 at 02:43:15PM +0100, Paolo Bonzini wrote:
> > On 1/24/24 13:55, Kirill A. Shutemov wrote:
> > > The patchset adds bits and pieces to get kexec (and crashkernel) work on
> > > TDX guest.
> > >
> > > The last patch implements CPU offlining according to the approved ACPI
> > > spec change poposal[1]. It unlocks kexec with all CPUs visible in the target
> > > kernel. It requires BIOS-side enabling. If it missing we fallback to booting
> > > 2nd kernel with single CPU.
> > >
> > > Please review. I would be glad for any feedback.
> >
> > Hi Kirill,
> >
> > I have a very basic question: is there a reason why this series does not
> > revert commit cb8eb06d50fc, "x86/virt/tdx: Disable TDX host support when
> > kexec is enabled"?
>
> My patchset enables kexec for TDX guest. The commit you refer blocks kexec
> for host. TDX host and guest have totally different problems with handling
> kexec. Kai looks on how to get host kexec functional.

Yeah, that was right there in the cover letter (and I should have
gotten a clue from the many references to CC_* constants...). Somebody
pointed me to this series as "the TDX kexec series from Intel" and I
had some tunnel vision issues. Sorry for the noise!

But since I have your attention, do you have a pointer to the
corresponding edk2 series? Thanks,

Paolo