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

From: Paolo Bonzini <pbonzini@redhat.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	 Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org,  "Rafael J. Wysocki" <rafael@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	 Adrian Hunter <adrian.hunter@intel.com>,
	 Kuppuswamy Sathyanarayanan
	<sathyanarayanan.kuppuswamy@linux.intel.com>,
	 Elena Reshetova <elena.reshetova@intel.com>,
	Jun Nakajima <jun.nakajima@intel.com>,
	 Rick Edgecombe <rick.p.edgecombe@intel.com>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	 "Kalra, Ashish" <ashish.kalra@amd.com>,
	Sean Christopherson <seanjc@google.com>,
	 "Huang, Kai" <kai.huang@intel.com>, Baoquan He <bhe@redhat.com>,
	kexec@lists.infradead.org,  linux-coco@lists.linux.dev,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCHv6 00/16] x86/tdx: Add kexec support
Date: Tue, 30 Jan 2024 15:59:34 +0100	[thread overview]
Message-ID: <CABgObfZiyx8hRsD37xZq5TNs9sRq48vLUxbOKa=HZ1vcr67sWQ@mail.gmail.com> (raw)
In-Reply-To: <g7jh422ild6c23hjxvf7q2xtygkumbpynz4hcops7nvg5izvpp@r3oyhvssph2o>

On Tue, Jan 30, 2024 at 3:34 PM Kirill A. Shutemov
<kirill.shutemov@linux.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