Received-SPF: pass (google.com: domain of linux-kernel+bounces-71129-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Date: Mon, 19 Feb 2024 11:32:59 +0100
From: Borislav Petkov <bp@alien8.de>
To: Ard Biesheuvel <ardb+git@google.com>
Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>,
	Kevin Loughlin <kevinloughlin@google.com>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	Dionna Glaze <dionnaglaze@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Justin Stitt <justinstitt@google.com>,
	Kees Cook <keescook@chromium.org>, Brian Gerst <brgerst@gmail.com>,
	linux-arch@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [PATCH v4 03/11] x86/startup_64: Simplify CR4 handling in
 startup code
Message-ID: <20240219103259.GAZdMuWzLGRg6SR1n9@fat_crate.local>
References: <20240213124143.1484862-13-ardb+git@google.com>
 <20240213124143.1484862-16-ardb+git@google.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <20240213124143.1484862-16-ardb+git@google.com>

On Tue, Feb 13, 2024 at 01:41:47PM +0100, Ard Biesheuvel wrote:
> -#ifdef CONFIG_X86_5LEVEL
> -	testb	$1, __pgtable_l5_enabled(%rip)
> -	jz	1f
> -	orl	$X86_CR4_LA57, %ecx
> -1:
> +	orl	$X86_CR4_MCE, %edx
>  #endif
> +	movq	%cr4, %rcx
> +	andl	%edx, %ecx

Let's just state it explicitly:

	/* Even if ignored in long mode, set PSE uniformly on all logical CPUs. */

> +	btsl	$X86_CR4_PSE_BIT, %ecx
>  	movq	%rcx, %cr4

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette