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 X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61CF4C433DF for ; Tue, 20 Oct 2020 01:38:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 06F0E22277 for ; Tue, 20 Oct 2020 01:38:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390077AbgJTBiQ (ORCPT ); Mon, 19 Oct 2020 21:38:16 -0400 Received: from mga05.intel.com ([192.55.52.43]:45332 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390045AbgJTBiQ (ORCPT ); Mon, 19 Oct 2020 21:38:16 -0400 IronPort-SDR: rbGGwftxRpfbZrAuVUcjV/s6W4yLGAfzdC6CdumkNRsd+ln/bcEt8NgUrXtIRD70clPDwMCEbm wxKJ3lJVVLVA== X-IronPort-AV: E=McAfee;i="6000,8403,9779"; a="251828260" X-IronPort-AV: E=Sophos;i="5.77,395,1596524400"; d="scan'208";a="251828260" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Oct 2020 18:38:15 -0700 IronPort-SDR: SJCmobtD43KKnOIBZd4CWbgAOvIIVgS6tTQcZacmJvNe5W3twhXpJ4mdwPMdbO/KIl+2SAo4d2 bpQ9l6TSZXyg== X-IronPort-AV: E=Sophos;i="5.77,395,1596524400"; d="scan'208";a="465743909" Received: from shuo-intel.sh.intel.com (HELO localhost) ([10.239.154.30]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Oct 2020 18:38:11 -0700 Date: Tue, 20 Oct 2020 09:38:09 +0800 From: Shuo A Liu To: Arvind Sankar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Greg Kroah-Hartman , "H . Peter Anvin" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Sean Christopherson , Yu Wang , Reinette Chatre , Yakui Zhao , Dave Hansen , Dan Williams , Fengwei Yin , Zhi Wang , Zhenyu Wang , Peter Zijlstra , Nick Desaulniers , Segher Boessenkool Subject: Re: [PATCH v5 04/17] x86/acrn: Introduce hypercall interfaces Message-ID: <20201020013809.GA11038@shuo-intel.sh.intel.com> References: <20201019061803.13298-1-shuo.a.liu@intel.com> <20201019061803.13298-5-shuo.a.liu@intel.com> <20201019221515.GA2875488@rani.riverdale.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20201019221515.GA2875488@rani.riverdale.lan> User-Agent: Mutt/1.8.3 (2017-05-23) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 19.Oct'20 at 18:15:15 -0400, Arvind Sankar wrote: >On Mon, Oct 19, 2020 at 02:17:50PM +0800, shuo.a.liu@intel.com wrote: >> From: Shuo Liu >> >> The Service VM communicates with the hypervisor via conventional >> hypercalls. VMCALL instruction is used to make the hypercalls. >> >> ACRN hypercall ABI: >> * Hypercall number is in R8 register. >> * Up to 2 parameters are in RDI and RSI registers. >> * Return value is in RAX register. >> >> Introduce the ACRN hypercall interfaces. Because GCC doesn't support R8 >> register as direct register constraints, use supported constraint as >> input with a explicit MOV to R8 in beginning of asm. >> >> +static inline long acrn_hypercall0(unsigned long hcall_id) >> +{ >> + long result; >> + >> + asm volatile("movl %1, %%r8d\n\t" >> + "vmcall\n\t" >> + : "=a" (result) >> + : "ir" (hcall_id) > >Is the hypercall id an unsigned long (64 bits) or an unsigned int (32 >bits)? This will generate broken assembly if the "r" option is chosen, >eg something like > movl %rdi, %r8d Yes, it can be an unsigned long. So do MOV explicitly. asm volatile("movq %1, %%r8\n\t" "vmcall\n\t" : "=a" (result) : "ir" (hcall_id) Thanks