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 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 8071EC021B8 for ; Tue, 4 Mar 2025 06:12:26 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tpLVL-0008QC-FD; Tue, 04 Mar 2025 01:11:47 -0500 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 1tpLVH-0008Q1-RQ for qemu-devel@nongnu.org; Tue, 04 Mar 2025 01:11:43 -0500 Received: from mgamail.intel.com ([198.175.65.15]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tpLVE-0004ez-Ew for qemu-devel@nongnu.org; Tue, 04 Mar 2025 01:11:43 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1741068701; x=1772604701; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=HHhKVtxadplL5mKHcw+YWQLXuPPV+DKKFP7OBci2gWQ=; b=Es/TsmPazteUeAAQkd9I6sXBY7oevC0uod1JDivhUY3hv8dRaPXpapui P+AuyGyUFQsHk3VaI3wZdV+OAGjbtc/9M4Nd4qtDUKnjNtSf84jaRRlEm 6b04Wxyxg67bHmuMXvTGhoXxqtTQeCsr6jdnP45/N78G5Tzmijcp2NpO5 7tc63OuLNZPSYMtwqYfd4Sh8Cp9Oeu8wQ9yIhF9Jdlc72yu0aIG6WcBGw ggjbYqZB13YmMmHvThdVV5MCLlwf6jiUCQPQTqDAoG2tJ8KUK6eGGqv/4 XRT6+uVss60bHVGQ4bc1rm6KeDlld01yq377K8z/4+eK5Wv5T5IafdWLY g==; X-CSE-ConnectionGUID: IG8n8vqsQ82M9TNlwGMy+w== X-CSE-MsgGUID: 8vXGbn5hRNqYY5YM5rmfaA== X-IronPort-AV: E=McAfee;i="6700,10204,11362"; a="45619428" X-IronPort-AV: E=Sophos;i="6.13,331,1732608000"; d="scan'208";a="45619428" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Mar 2025 22:11:35 -0800 X-CSE-ConnectionGUID: QAJh1PKgSEGQGeotrcQ+8w== X-CSE-MsgGUID: sEGnnyB9Sz2ZQAW7wcSnSg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.13,331,1732608000"; d="scan'208";a="141500769" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.124.247.1]) ([10.124.247.1]) by fmviesa002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Mar 2025 22:11:29 -0800 Message-ID: Date: Tue, 4 Mar 2025 14:11:27 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 02/10] target/i386: disable PERFCORE when "-pmu" is configured To: dongli.zhang@oracle.com, qemu-devel@nongnu.org, kvm@vger.kernel.org Cc: pbonzini@redhat.com, zhao1.liu@intel.com, mtosatti@redhat.com, sandipan.das@amd.com, babu.moger@amd.com, likexu@tencent.com, like.xu.linux@gmail.com, zhenyuw@linux.intel.com, groug@kaod.org, khorenko@virtuozzo.com, alexander.ivanov@virtuozzo.com, den@virtuozzo.com, davydov-max@yandex-team.ru, dapeng1.mi@linux.intel.com, joe.jin@oracle.com References: <20250302220112.17653-1-dongli.zhang@oracle.com> <20250302220112.17653-3-dongli.zhang@oracle.com> <99810e4f-f41d-4905-ae6d-1080b14fc8fd@intel.com> <0dcdd9c1-35e5-4cee-be0b-59113e01e73c@oracle.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: <0dcdd9c1-35e5-4cee-be0b-59113e01e73c@oracle.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=198.175.65.15; envelope-from=xiaoyao.li@intel.com; helo=mgamail.intel.com X-Spam_score_int: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, HK_RANDOM_ENVFROM=0.001, HK_RANDOM_FROM=0.998, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, 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: 2.1.29 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 On 3/4/2025 2:45 AM, dongli.zhang@oracle.com wrote: > Hi Xiaoyao, > > On 3/2/25 5:59 PM, Xiaoyao Li wrote: >> On 3/3/2025 6:00 AM, Dongli Zhang wrote: >>> Currently, AMD PMU support isn't determined based on CPUID, that is, the >>> "-pmu" option does not fully disable KVM AMD PMU virtualization. >>> >>> To minimize AMD PMU features, remove PERFCORE when "-pmu" is configured. >>> >>> To completely disable AMD PMU virtualization will be implemented via >>> KVM_CAP_PMU_CAPABILITY in upcoming patches. >>> >>> As a reminder, neither CPUID_EXT3_PERFCORE nor >>> CPUID_8000_0022_EAX_PERFMON_V2 is removed from env->features[] when "-pmu" >>> is configured. Developers should query whether they are supported via >>> cpu_x86_cpuid() rather than relying on env->features[] in future patches. >> >> I don't think it is the correct direction to go. >> >> env->features[] should be finalized before cpu_x86_cpuid() and env- >>> features[] needs to be able to be exposed to guest directly. This ensures >> guest and QEMU have the same view of CPUIDs and it simplifies things. >> >> We can adjust env->features[] by filtering all PMU related CPUIDs based on >> cpu->enable_pmu in x86_cpu_realizefn(). > > Thank you very much for suggestion. > > I see code like below in x86_cpu_realizefn() to edit env->features[]. > > 7982 /* On AMD CPUs, some CPUID[8000_0001].EDX bits must match the bits on > 7983 * CPUID[1].EDX. > 7984 */ > 7985 if (IS_AMD_CPU(env)) { > 7986 env->features[FEAT_8000_0001_EDX] &= ~CPUID_EXT2_AMD_ALIASES; > 7987 env->features[FEAT_8000_0001_EDX] |= (env->features[FEAT_1_EDX] > 7988 & CPUID_EXT2_AMD_ALIASES); > 7989 } > > I may do something similar to them for CPUID_EXT3_PERFCORE and > CPUID_8000_0022_EAX_PERFMON_V2. I just sent a series for CPUID_EXT_PDCM[1]. I think you can put CPUID_EXT3_PERFCORE and CPUID_8000_0022_EAX_PERFMON_V2 at the same place. [1] https://lore.kernel.org/qemu-devel/20250304052450.465445-1-xiaoyao.li@intel.com/T/#m31c6777131b6361d7c3af22b09532bdc785dbc06 > Dongli Zhang > > > >> >>> Suggested-by: Zhao Liu >>> Signed-off-by: Dongli Zhang >>> --- >>>   target/i386/cpu.c | 4 ++++ >>>   1 file changed, 4 insertions(+) >>> >>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c >>> index b6d6167910..61a671028a 100644 >>> --- a/target/i386/cpu.c >>> +++ b/target/i386/cpu.c >>> @@ -7115,6 +7115,10 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t >>> index, uint32_t count, >>>               !(env->hflags & HF_LMA_MASK)) { >>>               *edx &= ~CPUID_EXT2_SYSCALL; >>>           } >>> + >>> +        if (kvm_enabled() && IS_AMD_CPU(env) && !cpu->enable_pmu) { >>> +            *ecx &= ~CPUID_EXT3_PERFCORE; >>> +        } >>>           break; >>>       case 0x80000002: >>>       case 0x80000003: >> >