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 D3B7AC47DD7 for ; Fri, 19 Jan 2024 06:47:24 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rQieZ-00012b-Td; Fri, 19 Jan 2024 01:46:59 -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 1rQieU-00012J-KJ for qemu-devel@nongnu.org; Fri, 19 Jan 2024 01:46:54 -0500 Received: from mgamail.intel.com ([198.175.65.9]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rQieS-0006R0-RZ for qemu-devel@nongnu.org; Fri, 19 Jan 2024 01:46:54 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1705646813; x=1737182813; h=message-id:date:mime-version:to:cc:from:subject: content-transfer-encoding; bh=3pOu2TlHLp4Gw1kuTw80hDfDipa9mQm3xsM62NhMzj0=; b=Hf3TOxzp/UlyWJsqbIxYpA8qc7LeN0Ztwv0Kn0dRlt39CD887jXon9iH 2V8s/JgWJYkTry57oaP6N4vj9g/nvG21qnBouOiw0PZdX8zoqJmfzAIhu MSgt10bmn3gETwqhLHluWOed+LjmjfpVR+Cio9KtCE9uALb8PyCvwIWGy kFPT3cEL44pGZIKPGBvMAEvK8iCAkMENe34iRVlM8Iu6u2jYkCJ/5adTs ofNra0Jx2RHNWa03SwIW5WLXbsG0oixJyizYyQSQ8Cpi1n80aA77LFYeo 7Nrkb0pA1uJ7aqk4uOGQpNIySsFCm0Ejxd2c5sWiv26AHIjqfelis4aZ4 g==; X-IronPort-AV: E=McAfee;i="6600,9927,10956"; a="19259595" X-IronPort-AV: E=Sophos;i="6.05,204,1701158400"; d="scan'208";a="19259595" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jan 2024 22:46:50 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.05,204,1701158400"; d="scan'208";a="500682" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.238.2.234]) ([10.238.2.234]) by fmviesa003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jan 2024 22:46:48 -0800 Message-ID: <825f29d7-9112-45a2-b4a3-7d3b54c3c0a2@intel.com> Date: Fri, 19 Jan 2024 14:46:22 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US To: Paolo Bonzini , Marcelo Tosatti Cc: "qemu-devel@nongnu.org" , Lei Wang From: Xiaoyao Li Subject: Why invtsc (CPUID_APM_INVTSC) is unmigratable? Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=198.175.65.9; envelope-from=xiaoyao.li@intel.com; helo=mgamail.intel.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, DKIMWL_WL_HIGH=-1.806, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, HK_RANDOM_ENVFROM=0.998, HK_RANDOM_FROM=0.998, 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 I'm wondering why CPUID_APM_INVTSC is set as unmigratable_flags. Could anyone explain it? When the host supports invtsc, it can be exposed to guest. When the src VM has invtsc exposed, what will forbid it to be migrated to a dest that also supports VMs with invtsc exposed?