linux-kernel - Re: [PATCHv7 05/16] x86/kexec: Keep CR4.MCE set during kexec for TDX guest

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Date: Thu, 22 Feb 2024 23:04:56 +0100
From: Thomas Gleixner <tglx@...utronix.de>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>, Ingo Molnar
 <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, Dave Hansen
 <dave.hansen@...ux.intel.com>, x86@...nel.org
Cc: "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, "Kirill A. Shutemov"
 <kirill.shutemov@...ux.intel.com>
Subject: Re: [PATCHv7 05/16] x86/kexec: Keep CR4.MCE set during kexec for
 TDX guest

On Mon, Feb 12 2024 at 12:44, Kirill A. Shutemov wrote:

> TDX guests are not allowed to clear CR4.MCE. Attempt to clear it leads
> to #VE.
>
> Use alternatives to keep the flag during kexec for TDX guests.
>
> The change doesn't affect non-TDX-guest environments.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
> Reviewed-by: Kai Huang <kai.huang@...el.com>

Reviewed-by: Thomas Gleixner <tglx@...utronix.de>