From patchwork Mon Aug 12 10:14:34 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: EwanHai X-Patchwork-Id: 13760394 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id D391EC52D7C for ; Mon, 12 Aug 2024 10:22:23 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sdSB0-0005uR-1M; Mon, 12 Aug 2024 06:21:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sdSAy-0005pb-OS for qemu-devel@nongnu.org; Mon, 12 Aug 2024 06:21:20 -0400 Received: from mx2.zhaoxin.com ([203.110.167.99]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sdSAx-0002Fv-4V for qemu-devel@nongnu.org; Mon, 12 Aug 2024 06:21:20 -0400 X-ASG-Debug-ID: 1723458075-1eb14e31a6306f0001-jgbH7p Received: from ZXSHMBX3.zhaoxin.com (ZXSHMBX3.zhaoxin.com [10.28.252.165]) by mx2.zhaoxin.com with ESMTP id 1l21YLiNlJbzuEjO (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO); Mon, 12 Aug 2024 18:21:15 +0800 (CST) X-Barracuda-Envelope-From: EwanHai-oc@zhaoxin.com X-Barracuda-RBL-Trusted-Forwarder: 10.28.252.165 Received: from ZXSHMBX1.zhaoxin.com (10.28.252.163) by ZXSHMBX3.zhaoxin.com (10.28.252.165) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Mon, 12 Aug 2024 18:21:14 +0800 Received: from ZXSHMBX1.zhaoxin.com ([fe80::dcd1:d46d:263:77e]) by ZXSHMBX1.zhaoxin.com ([fe80::dcd1:d46d:263:77e%7]) with mapi id 15.01.2507.039; Mon, 12 Aug 2024 18:21:14 +0800 X-Barracuda-RBL-Trusted-Forwarder: 10.28.252.165 Received: from ewan-server.zhaoxin.com (10.28.66.62) by zxbjmbx1.zhaoxin.com (10.29.252.163) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Mon, 12 Aug 2024 18:14:37 +0800 From: EwanHai To: , , CC: , , , , , , Subject: [PATCH v4 4/4] target/i386: Mask CMPLegacy bit in CPUID[0x80000001].ECX for Zhaoxin CPUs Date: Mon, 12 Aug 2024 06:14:34 -0400 X-ASG-Orig-Subj: [PATCH v4 4/4] target/i386: Mask CMPLegacy bit in CPUID[0x80000001].ECX for Zhaoxin CPUs Message-ID: <20240812101434.3804790-5-ewanhai-oc@zhaoxin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240812101434.3804790-1-ewanhai-oc@zhaoxin.com> References: <20240812101434.3804790-1-ewanhai-oc@zhaoxin.com> MIME-Version: 1.0 X-Originating-IP: [10.28.66.62] X-ClientProxiedBy: zxbjmbx1.zhaoxin.com (10.29.252.163) To zxbjmbx1.zhaoxin.com (10.29.252.163) X-Moderation-Data: 8/12/2024 6:21:13 PM X-Barracuda-Connect: ZXSHMBX3.zhaoxin.com[10.28.252.165] X-Barracuda-Start-Time: 1723458075 X-Barracuda-Encrypted: ECDHE-RSA-AES128-GCM-SHA256 X-Barracuda-URL: https://10.28.252.36:4443/cgi-mod/mark.cgi X-Virus-Scanned: by bsmtpd at zhaoxin.com X-Barracuda-Scan-Msg-Size: 2287 X-Barracuda-BRTS-Status: 1 X-Barracuda-Bayes: INNOCENT GLOBAL 0.0000 1.0000 -2.0210 X-Barracuda-Spam-Score: -2.02 X-Barracuda-Spam-Status: No, SCORE=-2.02 using global scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=9.0 tests= X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.3.128930 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- Received-SPF: pass client-ip=203.110.167.99; envelope-from=EwanHai-oc@zhaoxin.com; helo=mx2.zhaoxin.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Zhaoxin CPUs (including vendors "Shanghai" and "Centaurhauls") handle the CMPLegacy bit similarly to Intel CPUs. Therefore, this commit masks the CMPLegacy bit in CPUID[0x80000001].ECX for Zhaoxin CPUs, just as it is done for Intel CPUs. AMD uses the CMPLegacy bit (CPUID[0x80000001].ECX.bit1) along with other CPUID information to enumerate platform topology (e.g., the number of logical processors per package). However, for Intel and other CPUs that follow Intel's behavior, CPUID[0x80000001].ECX.bit1 is reserved. - Impact on Intel and similar CPUs: This change has no effect on Intel and similar CPUs, as the goal is to accurately emulate CPU CPUID information. - Impact on Linux Guests running on Intel (and similar) vCPUs: During boot, Linux checks if the CPU supports Hyper-Threading. For the Linux kernel before v6.9, if it detects X86_FEATURE_CMP_LEGACY, it assumes Hyper-Threading is not supported. For Intel and similar vCPUs, if the CMPLegacy bit is not masked in CPUID[0x80000001].ECX, Linux will incorrectly assume that Hyper-Threading is not supported, even if the vCPU does support it. Signed-off-by: EwanHai Reviewed-by: Zhao Liu --- target/i386/cpu.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/target/i386/cpu.c b/target/i386/cpu.c index 95849c40ad..eb55d92e8a 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -6995,12 +6995,11 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, /* The Linux kernel checks for the CMPLegacy bit and * discards multiple thread information if it is set. - * So don't set it here for Intel to make Linux guests happy. + * So don't set it here for Intel(and other processors + * following Intel's behavior) to make Linux guests happy. */ if (threads_per_pkg > 1) { - if (env->cpuid_vendor1 != CPUID_VENDOR_INTEL_1 || - env->cpuid_vendor2 != CPUID_VENDOR_INTEL_2 || - env->cpuid_vendor3 != CPUID_VENDOR_INTEL_3) { + if (!IS_INTEL_CPU(env) && !IS_ZHAOXIN_CPU(env)) { *ecx |= 1 << 1; /* CmpLegacy bit */ } }