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

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Message-ID: <g7jh422ild6c23hjxvf7q2xtygkumbpynz4hcops7nvg5izvpp@r3oyhvssph2o>
Date: Tue, 30 Jan 2024 15:55:57 +0200
From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To: Paolo Bonzini <pbonzini@...hat.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 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.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov