From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 15259C4332F for ; Tue, 20 Dec 2022 12:04:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231248AbiLTMEp (ORCPT ); Tue, 20 Dec 2022 07:04:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59658 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229713AbiLTMEn (ORCPT ); Tue, 20 Dec 2022 07:04:43 -0500 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D00BE03F; Tue, 20 Dec 2022 04:04:42 -0800 (PST) Received: from zn.tnic (p5de8e9fe.dip0.t-ipconnect.de [93.232.233.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id DB86C1EC01E0; Tue, 20 Dec 2022 13:04:40 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1671537880; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=YmPCUZ1R0QUQOqRZ0OqQKPBGrzkADkw5btPSP+uFxWE=; b=VXb46m3IH27tFi5RRjOddleYF2fgg2kb0dmYnqtTe6NRX7NUssuAUNIPkcNeuQnUdHoNvY dQaX/H2OzSqzyueWORh3Y+HSdThQKf8MU32SB8oYaDsEG1+JwIlIbm0fwAcjld1Osp9Cid FkgRFSEciBVevEdYElpC9gDsOdAzWFg= Date: Tue, 20 Dec 2022 13:04:36 +0100 From: Borislav Petkov To: Rick Edgecombe Cc: x86@kernel.org, "H . Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H . J . Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , Weijiang Yang , "Kirill A . Shutemov" , John Allen , kcc@google.com, eranian@google.com, rppt@kernel.org, jamorris@linux.microsoft.com, dethoma@microsoft.com, akpm@linux-foundation.org, Andrew.Cooper3@citrix.com, christina.schimpe@intel.com Subject: Re: [PATCH v4 06/39] x86/fpu: Add helper for modifying xstate Message-ID: References: <20221203003606.6838-1-rick.p.edgecombe@intel.com> <20221203003606.6838-7-rick.p.edgecombe@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20221203003606.6838-7-rick.p.edgecombe@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Fri, Dec 02, 2022 at 04:35:33PM -0800, Rick Edgecombe wrote: > +void fpregs_lock_and_load(void) Fun naming :) > +{ > + /* > + * fpregs_lock() only disables preemption (mostly). So modifing state Unknown word [modifing] in comment. Suggestions: ['modifying',... > + * in an interrupt could screw up some in progress fpregs operation, > + * but appear to work. Warn about it. > + */ > + WARN_ON_ONCE(!irq_fpu_usable()); > + WARN_ON_ONCE(current->flags & PF_KTHREAD); > + > + fpregs_lock(); So it locks them here... /me goes further into the patchset aha, and the counterpart of this function is fpregs_unlock() so everything gets sandwitched between the two. Ok, I guess. > +EXPORT_SYMBOL_GPL(fpregs_lock_and_load); Exported for KVM? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette