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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E265C4332F for ; Tue, 20 Dec 2022 12:04:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 926F18E0003; Tue, 20 Dec 2022 07:04:52 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8D64E8E0001; Tue, 20 Dec 2022 07:04:52 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 79E678E0003; Tue, 20 Dec 2022 07:04:52 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 67FFF8E0001 for ; Tue, 20 Dec 2022 07:04:52 -0500 (EST) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 3203BAADEF for ; Tue, 20 Dec 2022 12:04:52 +0000 (UTC) X-FDA: 80262553224.26.147A07D Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by imf11.hostedemail.com (Postfix) with ESMTP id AA43840017 for ; Tue, 20 Dec 2022 12:04:42 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=temperror ("DNS error when getting key") header.d=alien8.de header.s=dkim header.b=VXb46m3I; spf=pass (imf11.hostedemail.com: domain of bp@alien8.de designates 5.9.137.197 as permitted sender) smtp.mailfrom=bp@alien8.de; dmarc=temperror reason="query timed out" header.from=alien8.de (policy=temperror) 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> X-Stat-Signature: bi87wybzc1x5xazc8i65o7jhmkw9nmrr X-Rspam-User: X-Rspamd-Queue-Id: AA43840017 X-Rspamd-Server: rspam06 X-HE-Tag: 1671537882-658186 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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