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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 92750C433E0 for ; Mon, 11 Jan 2021 04:39:39 +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 01EA7225AB for ; Mon, 11 Jan 2021 04:39:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 01EA7225AB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=yadro.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:47304 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kyozR-0004Be-Th for qemu-devel@archiver.kernel.org; Sun, 10 Jan 2021 23:39:37 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:56088) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kyoyF-0003kM-Kj for qemu-devel@nongnu.org; Sun, 10 Jan 2021 23:38:23 -0500 Received: from mta-02.yadro.com ([89.207.88.252]:47408 helo=mta-01.yadro.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kyoyD-0000ha-NP for qemu-devel@nongnu.org; Sun, 10 Jan 2021 23:38:23 -0500 Received: from localhost (unknown [127.0.0.1]) by mta-01.yadro.com (Postfix) with ESMTP id 5CE77412EB; Mon, 11 Jan 2021 04:38:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=yadro.com; h= in-reply-to:content-disposition:content-type:content-type :mime-version:references:message-id:subject:subject:from:from :date:date:received:received:received; s=mta-01; t=1610339897; x=1612154298; bh=Ju6gvDqQdoTI0whHAw1Vk3vAfNjvtLpPZSSRJjhXehA=; b= kZzd54mGu27oltlndPm9sL8aIQ63kt3orAFuuoGcynsIn8RqM9owBdJuOp0jAHeB sRuecYA6dQ2CRvyI9QCp0iCYdrWM/7+pu1Q40qYtmF+xazfgz6zZREAZjr8PSfnL Hi1UmF8KvjY2N8IUwAWOusoRvvM3cXYy2w6xVecexac= X-Virus-Scanned: amavisd-new at yadro.com Received: from mta-01.yadro.com ([127.0.0.1]) by localhost (mta-01.yadro.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 1FzIrDZ_-A-S; Mon, 11 Jan 2021 07:38:17 +0300 (MSK) Received: from T-EXCH-03.corp.yadro.com (t-exch-03.corp.yadro.com [172.17.100.103]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mta-01.yadro.com (Postfix) with ESMTPS id B41C34127E; Mon, 11 Jan 2021 07:38:17 +0300 (MSK) Received: from localhost (172.17.204.212) by T-EXCH-03.corp.yadro.com (172.17.100.103) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384) id 15.1.669.32; Mon, 11 Jan 2021 07:38:17 +0300 Date: Mon, 11 Jan 2021 07:38:43 +0300 From: Roman Bolshakov To: Hill Ma Subject: Re: [PATCH v2] hvf: guard xgetbv call. Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: X-Originating-IP: [172.17.204.212] X-ClientProxiedBy: T-EXCH-01.corp.yadro.com (172.17.10.101) To T-EXCH-03.corp.yadro.com (172.17.100.103) Received-SPF: pass client-ip=89.207.88.252; envelope-from=r.bolshakov@yadro.com; helo=mta-01.yadro.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, 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: richard.henderson@linaro.org, qemu-devel@nongnu.org, dirty@apple.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Sun, Jan 10, 2021 at 01:08:54PM -0800, Hill Ma wrote: > This prevents illegal instruction on cpus do not support xgetbv. > > Buglink: https://bugs.launchpad.net/qemu/+bug/1758819 > Signed-off-by: Hill Ma > --- > v2: xgetbv() modified based on feedback. > > target/i386/hvf/x86_cpuid.c | 28 +++++++++++++++++++--------- > 1 file changed, 19 insertions(+), 9 deletions(-) > > diff --git a/target/i386/hvf/x86_cpuid.c b/target/i386/hvf/x86_cpuid.c > index a6842912f5..edaa1b7da2 100644 > --- a/target/i386/hvf/x86_cpuid.c > +++ b/target/i386/hvf/x86_cpuid.c > @@ -27,15 +27,22 @@ > #include "vmx.h" > #include "sysemu/hvf.h" > > -static uint64_t xgetbv(uint32_t xcr) > +static bool xgetbv(uint32_t cpuid_ecx, uint32_t idx, uint64_t *xcr) > { > - uint32_t eax, edx; > + uint32_t xcrl, xcrh; > > - __asm__ volatile ("xgetbv" > - : "=a" (eax), "=d" (edx) > - : "c" (xcr)); > + if (cpuid_ecx & CPUID_EXT_OSXSAVE) { > + /* > + * The xgetbv instruction is not available to older versions of > + * the assembler, so we encode the instruction manually. > + */ > + asm(".byte 0x0f, 0x01, 0xd0" : "=a" (xcrl), "=d" (xcrh) : "c" (idx)); > > - return (((uint64_t)edx) << 32) | eax; > + *xcr = (((uint64_t)xcrh) << 32) | xcrl; > + return true; > + } > + > + return false; > } > > uint32_t hvf_get_supported_cpuid(uint32_t func, uint32_t idx, > @@ -100,11 +107,14 @@ uint32_t hvf_get_supported_cpuid(uint32_t func, uint32_t idx, > break; > case 0xD: > if (idx == 0) { > - uint64_t host_xcr0 = xgetbv(0); > - uint64_t supp_xcr0 = host_xcr0 & (XSTATE_FP_MASK | XSTATE_SSE_MASK | > + uint64_t supp_xcr0 = XSTATE_FP_MASK | XSTATE_SSE_MASK | > XSTATE_YMM_MASK | XSTATE_BNDREGS_MASK | > XSTATE_BNDCSR_MASK | XSTATE_OPMASK_MASK | > - XSTATE_ZMM_Hi256_MASK | XSTATE_Hi16_ZMM_MASK); > + XSTATE_ZMM_Hi256_MASK | XSTATE_Hi16_ZMM_MASK; > + uint64_t host_xcr0; > + if (xgetbv(ecx, 0, &host_xcr0)) { > + supp_xcr0 &= host_xcr0; Hi Hill, I'm not sure if eax should be modified with mask because the mask has no value per se. I.e. eax &= supp_xcr0 from below should be placed inside the if. It'd express clearly that eax is not modified unless xgetbv is supported. Thanks, Roman > + } > eax &= supp_xcr0; > } else if (idx == 1) { > hv_vmx_read_capability(HV_VMX_CAP_PROCBASED2, &cap); > -- > 2.20.1 (Apple Git-117) >