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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 65F6310F285F for ; Fri, 27 Mar 2026 17:18:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=z0YqKG8DvlQv4RLY3sMzq0x/Dmr5fV2Elxa83h4HfXo=; b=rGQxcJG3CW12aqYO1aVvxQ2xXf v5Liu8Dc2E8RlXknKi+Ihc1rhPv/su8BaUEkqarSm5e39ZR4Q/qBHOI+DXXV/JxXPmQH1PHbLBzbw JH19sGBOC7K06kOtzYyOqUHtKlgC7rfSTLqCY4uUq2X8p5DpaNSvGXvy8Bz+2y30FofFPb+KExEWN AV6AzIuT8+xcQbaw2w9xmvdbNZNzWN84A4vkUs/+RNqOXowgbyZrB7FQ3zc5xz2wu9RWCVgf1u7Gw 3AOL+EjqAekJTuLeTXAvIj9moQpSKddLbHq2kci3Ekz/4xwWrQKWc7mYD03yqSf0Q8ZScWXWXSaMu HqizHvaw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w6ApX-00000007r3T-1WbE; Fri, 27 Mar 2026 17:18:43 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w6ApU-00000007r35-09Bl for linux-arm-kernel@lists.infradead.org; Fri, 27 Mar 2026 17:18:41 +0000 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 83C3635AA; Fri, 27 Mar 2026 10:18:30 -0700 (PDT) Received: from arm.com (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4C71D3F99C; Fri, 27 Mar 2026 10:18:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1774631916; bh=aY/JswWMujYof83wSPNLXR7cuzHQPIe4Rii8L3Y7AjA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=NSCH7MHNUqegat7jNlT/WqiQ96q/ACI+/Rvxuacx95VZSPVtfc8cbhrWP3FAW9i61 2M951WUPxho9rGQ/ji69E2T44RnbgtSJdquxgk1vk1aGLk6LSEXnIX2vcWpetXf3E4 OMoBcyeimLzoBxQIKKcgSxj32zi2wIuhb9WoN8OA= Date: Fri, 27 Mar 2026 17:18:31 +0000 From: Catalin Marinas To: Yeoreum Yun Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, will@kernel.org, maz@kernel.org, oupton@kernel.org, miko.lenczewski@arm.com, kevin.brodsky@arm.com, broonie@kernel.org, ardb@kernel.org, suzuki.poulose@arm.com, lpieralisi@kernel.org, joey.gouly@arm.com, yuzenghui@huawei.com Subject: Re: (subset) [PATCH v17 0/8] support FEAT_LSUI Message-ID: References: <20260314175133.1084528-1-yeoreum.yun@arm.com> <177461632621.2272468.5197255307509898250.b4-ty@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260327_101840_228371_64F3E8D9 X-CRM114-Status: GOOD ( 10.15 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Mar 27, 2026 at 01:56:11PM +0000, Yeoreum Yun wrote: > > I decided to drop patch [6/8] (arm64: armv8_deprecated: disable swp > > emulation when FEAT_LSUI present). The way FEAT_LSUI support looks now, > > we still have uaccess_enable_privileged() working properly and we could > > even support SWP emulation using exclusives. While it's highly unlikely > > to see both 32-bit EL0 and FEAT_LSUI in practice, > > This is one of decisive reason to drop the swp emulation with LSUI > (https://lore.kernel.org/all/aXDbBKhE1SdCW6q4@willie-the-truck/) Ah, I forgot about this discussion. It's a valid point, I just thought it's unnecessary given that __uaccess_disable_hw_pan() still works. If we want strict no PAN, I can add it back (really small patch). I wonder whether we should also add a WARN_ON_ONCE(cpus_have_final_cap(ARM64_HAS_LSUI)) to the pan disabling function. Not urgent though. -- Catalin