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 672D1C433F5 for ; Mon, 24 Jan 2022 23:37:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2359734AbiAXXes (ORCPT ); Mon, 24 Jan 2022 18:34:48 -0500 Received: from mga04.intel.com ([192.55.52.120]:1125 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1838200AbiAXWqE (ORCPT ); Mon, 24 Jan 2022 17:46:04 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1643064364; x=1674600364; h=message-id:date:mime-version:to:cc:references:from: subject:in-reply-to:content-transfer-encoding; bh=0yjYC5cSG6wMR0icUJQxGPCW1Tr8fzyk1/f5bniTbYQ=; b=DY6Hu/1A68drM+e9RenNZm/Gfw55PMgAvdaHKR8EjE/UIephx9+QT58t enW839gzq0Txn4xmlkUmUAoHoN5adqrCEhKX9ayRS89xtaVilAeiOPbPA OgUzYiCE36E8YtGQlmt8HmF4QGl09cnPXn3uhOkcwZNrDtl/fAuZchnPP 0hNiPAL5SXO2wAcNEzZiUjWxY3YJ1r78y/J4gpbbIjLz+K9g715yKblAm 3JaoZMi+uczNc/QzfIr8rIk0qksjGKmIAwKnidG9iZF5Zjb5vzGOlg2Rt 0ufThj0aw4sMn/MefHjLiBEh+uPRFjr0FkKOhVzHI0ML5yO4k2Lq49goz w==; X-IronPort-AV: E=McAfee;i="6200,9189,10237"; a="244998192" X-IronPort-AV: E=Sophos;i="5.88,313,1635231600"; d="scan'208";a="244998192" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jan 2022 14:40:46 -0800 X-IronPort-AV: E=Sophos;i="5.88,313,1635231600"; d="scan'208";a="580544212" Received: from jncomo-mobl.amr.corp.intel.com (HELO [10.251.27.220]) ([10.251.27.220]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jan 2022 14:40:45 -0800 Message-ID: <12fb2758-8c06-8ab8-03d8-d77bd1edfce1@intel.com> Date: Mon, 24 Jan 2022 14:40:41 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Content-Language: en-US To: "Kirill A. Shutemov" , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, luto@kernel.org, peterz@infradead.org Cc: sathyanarayanan.kuppuswamy@linux.intel.com, aarcange@redhat.com, ak@linux.intel.com, dan.j.williams@intel.com, david@redhat.com, hpa@zytor.com, jgross@suse.com, jmattson@google.com, joro@8bytes.org, jpoimboe@redhat.com, knsathya@kernel.org, pbonzini@redhat.com, sdeep@vmware.com, seanjc@google.com, tony.luck@intel.com, vkuznets@redhat.com, wanpengli@tencent.com, x86@kernel.org, linux-kernel@vger.kernel.org References: <20220124150215.36893-1-kirill.shutemov@linux.intel.com> <20220124150215.36893-9-kirill.shutemov@linux.intel.com> From: Dave Hansen Subject: Re: [PATCHv2 08/29] x86/tdx: Handle in-kernel MMIO In-Reply-To: <20220124150215.36893-9-kirill.shutemov@linux.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > +static bool tdx_mmio(int size, bool write, unsigned long addr, > + unsigned long *val) > +{ > + struct tdx_hypercall_output out; > + u64 err; > + > + err = _tdx_hypercall(EXIT_REASON_EPT_VIOLATION, size, write, > + addr, *val, &out); > + if (err) > + return true; > + > + *val = out.r11; > + return false; > +} > + > +static bool tdx_mmio_read(int size, unsigned long addr, unsigned long *val) > +{ > + return tdx_mmio(size, false, addr, val); > +} > + > +static bool tdx_mmio_write(int size, unsigned long addr, unsigned long *val) > +{ > + return tdx_mmio(size, true, addr, val); > +} > + > +static int tdx_handle_mmio(struct pt_regs *regs, struct ve_info *ve) > +{ ... > + bool err; I'll agree with Josh on one point: "bool err" _is_ weird. Things tend to either return int with 0 for success or bool with true for success. The tdx_handle*() ones seem OK to me. It's pretty normal to have a literal "handler" return true if things were handled. I'd probably just make tdx_mmio() return an int. It seems to only able to return -EFAULT anyway, so changing the return from bool->int and doing: - return false; + return -EFAULT; isn't exactly a heavy lift.