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=-17.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 45224C48BC2 for ; Sun, 27 Jun 2021 21:08:53 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0580F61C17 for ; Sun, 27 Jun 2021 21:08:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0580F61C17 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=csgraf.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:58630 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lxc1M-0002sh-3v for qemu-devel@archiver.kernel.org; Sun, 27 Jun 2021 17:08:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38292) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lxc0X-00020b-4f; Sun, 27 Jun 2021 17:08:01 -0400 Received: from mail.csgraf.de ([85.25.223.15]:32998 helo=zulu616.server4you.de) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lxc0U-0002Jz-JE; Sun, 27 Jun 2021 17:08:00 -0400 Received: from MacBook-Air.alex.local (dynamic-077-002-101-004.77.2.pool.telefonica.de [77.2.101.4]) by csgraf.de (Postfix) with ESMTPSA id AF34960801CD; Sun, 27 Jun 2021 23:07:55 +0200 (CEST) Subject: Re: [PATCH v8 19/19] hvf: arm: Handle Windows 10 SMC call To: Peter Maydell References: <20210519202253.76782-1-agraf@csgraf.de> <20210519202253.76782-20-agraf@csgraf.de> From: Alexander Graf Message-ID: Date: Sun, 27 Jun 2021 23:07:55 +0200 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Received-SPF: pass client-ip=85.25.223.15; envelope-from=agraf@csgraf.de; helo=zulu616.server4you.de X-Spam_score_int: -36 X-Spam_score: -3.7 X-Spam_bar: --- X-Spam_report: (-3.7 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-1.765, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Eduardo Habkost , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , Richard Henderson , QEMU Developers , Cameron Esfahani , Roman Bolshakov , qemu-arm , Frank Yang , Paolo Bonzini , Peter Collingbourne Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 15.06.21 11:31, Peter Maydell wrote: > On Wed, 19 May 2021 at 21:23, Alexander Graf wrote: >> Windows 10 calls an SMCCC call via SMC unconditionally on boot. It lives >> in the trusted application call number space, but its purpose is unknown. >> >> In our current SMC implementation, we inject a UDEF for unknown SMC calls, >> including this one. However, Windows breaks on boot when we do this. Instead, >> let's return an error code. >> >> With this patch applied I can successfully boot the current Windows 10 >> Insider Preview in HVF. >> >> Signed-off-by: Alexander Graf >> >> --- >> >> v7 -> v8: >> >> - fix checkpatch >> --- >> target/arm/hvf/hvf.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c >> index 65c33e2a14..be670af578 100644 >> --- a/target/arm/hvf/hvf.c >> +++ b/target/arm/hvf/hvf.c >> @@ -931,6 +931,10 @@ int hvf_vcpu_exec(CPUState *cpu) >> cpu_synchronize_state(cpu); >> if (!hvf_handle_psci_call(cpu)) { >> advance_pc = true; >> + } else if (env->xregs[0] == QEMU_SMCCC_TC_WINDOWS10_BOOT) { >> + /* This special SMC is called by Windows 10 on boot. Return error */ >> + env->xregs[0] = -1; >> + advance_pc = true; >> } else { >> trace_hvf_unknown_smc(env->xregs[0]); >> hvf_raise_exception(env, EXCP_UDEF, syn_uncategorized()); > Where can I find documentation on what this SMC call is and what > it's supposed to do ? It's 0xc3000001 which according to the SMCCC spec [1] means OR'ed values of the following: 0x80000000 = Fast Call 0x40000000 = SMC64 0x03000000 = OEM Service Calls 0x00000001 = Function number 1 So, uh. I'm not sure how to answer the question above. I don't have source level access to Windows to read what the call is supposed to do :). But it's definitely calling something OEM specific that it really shouldn't be callling. Reading the SMCCC spec section 5.2, unknown SMCCC calls should return -1. It advises against probing by just calling them, but does not specify any other fault behavior than the -1 return (such as the #UDEF we inject in TCG). Alex [1] https://developer.arm.com/documentation/den0028/latest