linux-kernel - Re: [PATCHv3 00/14] x86/tdx: Add kexec support

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Message-ID: <20231121092430.fmkzpcjwhidkiqjv@box.shutemov.name>
Date:   Tue, 21 Nov 2023 12:24:30 +0300
From:   "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To:     Tao Liu <ltao@...hat.com>
Cc:     Baoquan He <bhe@...hat.com>, 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>, kexec@...ts.infradead.org,
        linux-coco@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv3 00/14] x86/tdx: Add kexec support

On Tue, Nov 21, 2023 at 05:10:01PM +0800, Tao Liu wrote:
> > > My colleague Tao helped to double check this, he got the same testing result.
> > > Plesae
> > > 1) what can we do to enable the multiple cpu support for kexec reboot?
> >
> > You would need a patched BIOS image. I've hacked one[1] for my testing.
> > But it only works if kernel runs in 4-level paging mode (specify no5lvl in
> > kernel command line).
> >
> > BIOS folks work on proper patch, but it is not ready yet.
> >
> > [1] https://gist.github.com/kiryl/e1dc1719e0c990b3ceee5d8de8dbf332
> >
> Thanks a lot for providing the BIOS patch. One more question, is the
> patched BIOS image for the host physical machine or for the tdx guest
> vm?

For the guest.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov