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 50BEFC433EF for ; Tue, 28 Jun 2022 00:05:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242411AbiF1AE7 (ORCPT ); Mon, 27 Jun 2022 20:04:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40584 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229512AbiF1AE6 (ORCPT ); Mon, 27 Jun 2022 20:04:58 -0400 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CC94955BD; Mon, 27 Jun 2022 17:04:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1656374697; x=1687910697; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=vqC6za7ZN5iR/9XFisZNkkM6BFIN5Rq0bwxydFNlIpw=; b=F10pxssDNMWSeBlKTDcYA9Kxs34RT7s7Uq3gmbsfUJz9jr5yZ3dwl9EI vV6csWik8QiDNRh9MqGkzl//jo/TnQwcytvm4IJcIk2KzOl3H+dCEbixY pTKLAj8/KthURIKukp8nuKFsgyTJbKyo2/OlHWgeMv5U2L0HIL3gXCPV7 YWxzwguW3v7Tlxa7YGB62NBsMVvc1sFXE6Jj/enZhvAdf3/a+adl2Vvux XUAHO+NVKm5Amul9cC1dz7hEno66piupla60rBwDkT4dD0bxYuVQqZvpa UByryYalIF4t0lRLym58BIMHGd+DZHHHcAP8VpSV6MTd6o1EoFW+TLX2o w==; X-IronPort-AV: E=McAfee;i="6400,9594,10391"; a="261395817" X-IronPort-AV: E=Sophos;i="5.92,227,1650956400"; d="scan'208";a="261395817" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jun 2022 17:04:57 -0700 X-IronPort-AV: E=Sophos;i="5.92,227,1650956400"; d="scan'208";a="732526044" Received: from jsagoe-mobl1.amr.corp.intel.com (HELO [10.209.12.66]) ([10.209.12.66]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jun 2022 17:04:57 -0700 Message-ID: <606f7526-23b8-a114-020f-b5fcdeecf90b@intel.com> Date: Mon, 27 Jun 2022 17:03:58 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH v5 08/22] x86/virt/tdx: Shut down TDX module in case of error Content-Language: en-US To: Kai Huang , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: seanjc@google.com, pbonzini@redhat.com, len.brown@intel.com, tony.luck@intel.com, rafael.j.wysocki@intel.com, reinette.chatre@intel.com, dan.j.williams@intel.com, peterz@infradead.org, ak@linux.intel.com, kirill.shutemov@linux.intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, isaku.yamahata@intel.com References: <89fffc70cdbb74c80bb324364b712ec41e5f8b91.1655894131.git.kai.huang@intel.com> <765a20f1-681d-33c2-68e9-24cc249fe6f9@intel.com> <77c90075-79d4-7cc7-f266-1b67e586513b@intel.com> <2b94afd608303f104376e6a775b211714e34bc7e.camel@intel.com> <6ed2746d-f44c-4511-7373-5706dd7c3f0f@intel.com> From: Dave Hansen In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 6/27/22 16:59, Kai Huang wrote: > If so, in the assembly, I think we can just XOR TDX_SW_ERROR to the %rax and > return %rax: > > 2: > /* > * SEAMCALL caused #GP or #UD. By reaching here %eax contains > * the trap number. Convert trap number to TDX error code by setting > * TDX_SW_ERROR to the high 32-bits of %rax. > */ > xorq $TDX_SW_ERROR, %rax > > How does this look? I guess it doesn't matter if you know the things being masked together are padded correctly, but I probably would have done a straight OR, not XOR. Otherwise, I think that looks OK. Simplifies the assembly for sure.