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[23.128.96.33]) by mx.google.com with ESMTPS id ck8-20020a056a02090800b00563ee04bbafsi9480602pgb.837.2023.11.27.07.07.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Nov 2023 07:07:51 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.33 as permitted sender) client-ip=23.128.96.33; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.33 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=arm.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by lipwig.vger.email (Postfix) with ESMTP id BB93A809B9CD; Mon, 27 Nov 2023 07:07:48 -0800 (PST) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.11 at lipwig.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233731AbjK0PH2 (ORCPT + 99 others); Mon, 27 Nov 2023 10:07:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59754 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233754AbjK0PH0 (ORCPT ); Mon, 27 Nov 2023 10:07:26 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id C5ECEC6; Mon, 27 Nov 2023 07:07:32 -0800 (PST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 288502F4; Mon, 27 Nov 2023 07:08:20 -0800 (PST) Received: from raptor (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4905E3F6C4; Mon, 27 Nov 2023 07:07:27 -0800 (PST) Date: Mon, 27 Nov 2023 15:07:24 +0000 From: Alexandru Elisei To: David Hildenbrand Cc: catalin.marinas@arm.com, will@kernel.org, oliver.upton@linux.dev, maz@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, arnd@arndb.de, akpm@linux-foundation.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, mhiramat@kernel.org, rppt@kernel.org, hughd@google.com, pcc@google.com, steven.price@arm.com, anshuman.khandual@arm.com, vincenzo.frascino@arm.com, eugenis@google.com, kcc@google.com, hyesoo.yu@samsung.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH RFC v2 14/27] arm64: mte: Disable dynamic tag storage management if HW KASAN is enabled Message-ID: References: <20231119165721.9849-1-alexandru.elisei@arm.com> <20231119165721.9849-15-alexandru.elisei@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-0.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lipwig.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (lipwig.vger.email [0.0.0.0]); Mon, 27 Nov 2023 07:07:48 -0800 (PST) Hi, On Fri, Nov 24, 2023 at 08:54:12PM +0100, David Hildenbrand wrote: > On 19.11.23 17:57, Alexandru Elisei wrote: > > To be able to reserve the tag storage associated with a page requires that > > the tag storage page can be migrated. > > > > When HW KASAN is enabled, the kernel allocates pages, which are now tagged, > > in non-preemptible contexts, which can make reserving the associate tag > > storage impossible. > > I assume that it's the only in-kernel user that actually requires tagged > memory (besides for user space), correct? Indeed, this is the case. I'll expand the commit message to be more clear about it. Thanks, Alex > > -- > Cheers, > > David / dhildenb >