From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B7330190696; Wed, 11 Jun 2025 01:47:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.9 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749606430; cv=none; b=OTUlcPL9WVZxV3gESmiVLzBnIQ0Tgxp/KWmDyFyC1raNoNUdTjO5rh6Sn+ePqZCdXsnqPRVVgxCpeJyrTkqcoeQWeAiq2wMdhEXnXOlL9of2itCfe+A8/4LhVH6dWycMvoKLUlDSu3z5AZiqk0FFPCxfRYtvuC/NaitK3xNYBrI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749606430; c=relaxed/simple; bh=Vz3tyYbLL715NajQX5ascY0JphbQ9TleSKtDEjg0kIE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=FgT6bdBEOIb5KjbHKJtjqenykiUaNt2DsCi0ZIk6uMialc+XSNnKFRWDNlYZep+S43aSlI6NIYVRNgwL3bLbhVBhR6KmruscwEf4EH+VwUkSHkIU05sALts1XoJu5iTnOzxiV+YNdRVWWiJ0DZFO9OVa4ct2H1EJ3EYU2juI7AQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=axUAmMAk; arc=none smtp.client-ip=192.198.163.9 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="axUAmMAk" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1749606429; x=1781142429; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=Vz3tyYbLL715NajQX5ascY0JphbQ9TleSKtDEjg0kIE=; b=axUAmMAkbMKs4VW7nZVrjFmXRm57yXfGAwUTb93WfU0GOzRR+sLdcfQx dBadiQil8S7kunDcS2LV/vMMR1/7WNhEdS6B0e8LyXJyv8SnkXt9WGY0p FTZBhtmX9Wo3cWIEj34/YwKtOqkfJCn2lhSsOfgKT6i44nlr5Bme/Hjht rkBqmDLFU73R6J7jZ03A0RAhjPyt4WO8t8DiAIuFjZPG0hm6R7A/vCW5J W23UJ/o5B5oCliXktDZWGQxiJ90h+uoTEXw6WyFsk+KWZA7BMLpr2rSYW X89Fu6QmpQPtV5GXKi7WKHbMznOqlI2GBAc16Wp6p8TG39/cwLFZ3fiIj g==; X-CSE-ConnectionGUID: S59wtTKNS2OsaPQNJtKn5A== X-CSE-MsgGUID: mys51MRNR8qVSlOxUFN3HA== X-IronPort-AV: E=McAfee;i="6800,10657,11460"; a="62389632" X-IronPort-AV: E=Sophos;i="6.16,226,1744095600"; d="scan'208";a="62389632" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by fmvoesa103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Jun 2025 18:47:08 -0700 X-CSE-ConnectionGUID: 6gwus4kvSGacmOojacMNRw== X-CSE-MsgGUID: VU9FL7jQRqS5iyaLT+Db2w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,226,1744095600"; d="scan'208";a="177952016" Received: from dapengmi-mobl1.ccr.corp.intel.com (HELO [10.124.245.144]) ([10.124.245.144]) by orviesa002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Jun 2025 18:47:06 -0700 Message-ID: <2e32978a-25c4-45a9-bdff-3097bb3abcdd@linux.intel.com> Date: Wed, 11 Jun 2025 09:47:04 +0800 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 3/3] KVM: selftests: Test behavior of KVM_X86_DISABLE_EXITS_APERFMPERF To: Jim Mattson Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Sean Christopherson , Paolo Bonzini References: <20250530185239.2335185-1-jmattson@google.com> <20250530185239.2335185-4-jmattson@google.com> <574f8adc-6aea-4460-9211-685091a30f5e@linux.intel.com> Content-Language: en-US From: "Mi, Dapeng" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 6/11/2025 12:59 AM, Jim Mattson wrote: > On Tue, Jun 10, 2025 at 1:42 AM Mi, Dapeng wrote: >> >> On 5/31/2025 2:52 AM, Jim Mattson wrote: >>> For a VCPU thread pinned to a single LPU, verify that interleaved host >>> and guest reads of IA32_[AM]PERF return strictly increasing values when >>> APERFMPERF exiting is disabled. >> Should we consider the possible overflow case of these 2 MSRs although it >> could be extremely rare? Thanks. > Unless someone moves the MSRs forward, at current frequencies, the > machine will have to be up for more than 100 years. I'll be long dead > by then. 😂 > > Note that frequency invariant scheduling doesn't accommodate overflow > either. If the MSRs overflow, frequency invariant scheduling is > disabled. Agree.