linux-kernel - Re: [PATCHv6 04/16] x86/efi: Move runtime service initialization to arch/x86

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Message-ID: <aqkhzspx6bh7u6gkxkgp7ih3onk27rot7ojwvwvsk6c7zv4ror@ilbd7wt56jxi>
Date: Fri, 20 Jun 2025 20:42:00 +0300
From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To: Dave Hansen <dave.hansen@...el.com>
Cc: Andy Lutomirski <luto@...nel.org>, 
	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, "H. Peter Anvin" <hpa@...or.com>, 
	Peter Zijlstra <peterz@...radead.org>, Ard Biesheuvel <ardb@...nel.org>, 
	"Paul E. McKenney" <paulmck@...nel.org>, Josh Poimboeuf <jpoimboe@...nel.org>, 
	Xiongwei Song <xiongwei.song@...driver.com>, Xin Li <xin3.li@...el.com>, 
	"Mike Rapoport (IBM)" <rppt@...nel.org>, Brijesh Singh <brijesh.singh@....com>, 
	Michael Roth <michael.roth@....com>, Tony Luck <tony.luck@...el.com>, 
	Alexey Kardashevskiy <aik@....com>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>, 
	Jonathan Corbet <corbet@....net>, Sohil Mehta <sohil.mehta@...el.com>, 
	Ingo Molnar <mingo@...nel.org>, Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>, 
	Daniel Sneddon <daniel.sneddon@...ux.intel.com>, Kai Huang <kai.huang@...el.com>, 
	Sandipan Das <sandipan.das@....com>, Breno Leitao <leitao@...ian.org>, 
	Rick Edgecombe <rick.p.edgecombe@...el.com>, Alexei Starovoitov <ast@...nel.org>, 
	Hou Tao <houtao1@...wei.com>, Juergen Gross <jgross@...e.com>, 
	Vegard Nossum <vegard.nossum@...cle.com>, Kees Cook <kees@...nel.org>, Eric Biggers <ebiggers@...gle.com>, 
	Jason Gunthorpe <jgg@...pe.ca>, "Masami Hiramatsu (Google)" <mhiramat@...nel.org>, 
	Andrew Morton <akpm@...ux-foundation.org>, Luis Chamberlain <mcgrof@...nel.org>, 
	Yuntao Wang <ytcoode@...il.com>, Rasmus Villemoes <linux@...musvillemoes.dk>, 
	Christophe Leroy <christophe.leroy@...roup.eu>, Tejun Heo <tj@...nel.org>, Changbin Du <changbin.du@...wei.com>, 
	Huang Shijie <shijie@...amperecomputing.com>, Geert Uytterhoeven <geert+renesas@...der.be>, 
	Namhyung Kim <namhyung@...nel.org>, Arnaldo Carvalho de Melo <acme@...hat.com>, 
	linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org, 
	linux-mm@...ck.org
Subject: Re: [PATCHv6 04/16] x86/efi: Move runtime service initialization to
 arch/x86

On Fri, Jun 20, 2025 at 08:35:14AM -0700, Dave Hansen wrote:
> On 6/20/25 06:53, Kirill A. Shutemov wrote:
> > From: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
> > 
> > The EFI call in start_kernel() is guarded by #ifdef CONFIG_X86. Move
> > the thing to the arch_cpu_finalize_init() path on x86 and get rid of
> > the #ifdef in start_kernel().
> 
> What does this have to do with LASS?

It is required to move CR pinning below it and allow to disable CR4.LASS
temporarily during EFI initialization.

> Is there any reason not to just pull this in to tip now as a cleanup? It
> looks good regardless of what it does to LASS.

I am totally fine with applying it right away.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov