From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 2056C39B951; Fri, 27 Mar 2026 17:18:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774631919; cv=none; b=KjR/JLlYeSAkFLJ06Ioz/Y0KURI2S+RM8U2Rmsuk+s+xI9MD4NReBxw9ye1dTw036OSKlOhiRr0vG68qdPDEDdAPVSvfg1t4SkE++KIWFvq/capnsm86a7fnUa+GTBgzXKLNrt2GZbr+SrOBMy9pPoaMg8dIViCsvVY4x8JWZNo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774631919; c=relaxed/simple; bh=aY/JswWMujYof83wSPNLXR7cuzHQPIe4Rii8L3Y7AjA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=njI66IbsJcBxex4AMPysZRrDONgbxTUWyxPl1Iuo5kiwMvkCS64oQIdbeuEGmulkvCquXNnZrFAYNEO3O+ONezfSsqfBI2zh3s5b/PmS54mtXX966tiDVyC2wF6MmoyCmnSV4olYTDfEn6b5NYHJxCYpLVkdk9Fu01Z3hPrtFTk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=NSCH7MHN; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="NSCH7MHN" 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> 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=us-ascii Content-Disposition: inline In-Reply-To: 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