From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.alien8.de (mail.alien8.de [65.109.113.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1D09A3EB102 for ; Tue, 9 Jun 2026 21:41:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=65.109.113.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781041307; cv=none; b=aKAddroLKoRZhW/pNHYgkIVeahAzkit7KUY/IaYDfe8M+t0oL7J+cm/JKQIkxWPjTGo6FPacOcKO/ReCvZ8OAARkEsEql3BrKWVaKJuN/MR3Bt9ZrqiTdmxZS8fUhmxH/WOuWaWEa6lGaXLJvKQ36W7jsnyvJnzSfktlCGgx8+k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781041307; c=relaxed/simple; bh=fOfobMJvZsKblbqrJfjwG+hHmpuexfrl6lok271NDRM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=hXgbHT3fTzQsRCSwYmxLCul/oHH0r1CmDrpkX4Iqh8gDvwDW/PxWjvgRe9epp16n9tRqaUXPOW3CY/ZJBVkbO3xqrQVkfd/HdvYThsi0dHqNb5vL1K+BFEODtBuWSMPN2F1M2iVb7B5wxPtImYjkXR0/B9ZpT+pksSC+Yi+sXmo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de; spf=pass smtp.mailfrom=alien8.de; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b=M1rqba3I; arc=none smtp.client-ip=65.109.113.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=alien8.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b="M1rqba3I" Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTP id 3710340E0214; Tue, 9 Jun 2026 21:41:34 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mail.alien8.de Authentication-Results: mail.alien8.de (amavisd-new); dkim=pass (4096-bit key) header.d=alien8.de Received: from mail.alien8.de ([127.0.0.1]) by localhost (mail.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id 6K6rgw2KnJb5; Tue, 9 Jun 2026 21:41:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=alien8; t=1781041284; bh=JjjVNRHiUVVgc9lYVAjGGcC+uYJXAjhvlJw8P6OEM/Q=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=M1rqba3I3fFYC3Qqi97pmFjIh8k5DfCFaSYDTQdHXNVYgzKRzEUXGq6eF8WGWCFi2 AxRsXYdzmOL20+RFA9BaaWUz/t+aDFDeCHDMUiharJA6JAupVCMPQsdRw80pFeO7el ml7D0iw7gfx2eWTzlBlIqqTOlBqUCyS71TypDaEN1ERMmB/xj+iUczRGaNzMG6M5CI DcZk1CA4I0MkmnDVVH1D/cD2DAZjK6AWFXFIQYSPgNiG2tr2w45wW43xEDcpuZaCv/ 7UMtc4I5pEGzSDgSGNeTjvbmI/tDtBsdoIAC6URA1ukZfx20YqYIJIU04xyw3hGh7F NgkMWZsyN4K+KdOzaHGo2Evvk+xn3ISzo1P8/k+L87ADm/54+/y8+sit3lWiZIUBS2 vodWOMtLNbbrlzt16Z3H0WkG/YnFbGLHYmQ4e1LlEcDC+2sKFSCXmM30WnspNmu/Ib jsQ/NuCfYrU/4L/BmrOhoGQSxUiIv+SLCFot/NxvVmKInf+QEuej57tX80Ohnpy2rz uUoR/uHBBhtOvSFCnNxlsuzWRQk9afhS+X73SqNDw9IHdUZAm0LQoagCywUELMN2Lg j2t7pFlLueMWk1oPnXfRCS+aKFpQcSdXhaIWCHgdf0Rn5LuUbEK/Dhi79GdZFpAPgf 4FK80qf/ttMwCge8A8PTfaHo= Received: from stx.tnic (unknown [IPv6:2600:1700:38ca:c00::3a]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id A3AAF40E0031; Tue, 9 Jun 2026 21:41:18 +0000 (UTC) Date: Tue, 9 Jun 2026 14:41:15 -0700 From: Borislav Petkov To: Jim Mattson Cc: Thomas Gleixner , x86@kernel.org, linux-kernel@vger.kernel.org, yosry@kernel.org Subject: Re: [PATCH 1/1] x86/CPU/AMD: Avoid racy updates to MSR_K7_HWCR in set_cpuid_faulting() Message-ID: <20260609214115.GAaiiIexPUw8aWoT8A@fat_crate.local> References: <20260609211611.466231-1-jmattson@google.com> <20260609211611.466231-2-jmattson@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260609211611.466231-2-jmattson@google.com> On Tue, Jun 09, 2026 at 02:15:47PM -0700, Jim Mattson wrote: > + unsigned long flags; > + > + local_irq_save(flags); > if (on) > msr_set_bit(MSR_K7_HWCR, MSR_K7_HWCR_CPUID_USER_DIS_BIT); > else > msr_clear_bit(MSR_K7_HWCR, MSR_K7_HWCR_CPUID_USER_DIS_BIT); > + local_irq_restore(flags); > } Can we carve out this logic that modifies bits in HWCR into a separate function and call it from everywhere it needs so that it is very obvious that synchronization needs to happen? Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette