From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.17]) (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 CD74434DCD6; Tue, 18 Aug 2026 18:30:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.17 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787077841; cv=none; b=b+UHCKJypWbBrtTDumu+FZj88jbHhnkZhVKfUZt4zHfOJGtiQKjkAUJdSBgyghrRhEA7YrANQfnIRpA1ajNhlW+SkxCS2xkiv9gq1iSxQ7QcM5/sN+RV5R6BJZwrR6Gqc/tA5VrFmXMIeINaCPnCcwmRch/Z5BM5qQHJD1Hdfgs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787077841; c=relaxed/simple; bh=OifyDmtF7aGLxK+GIfjGGWqID3Pft2TdvjfmPOg6RNw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=qFRwGkU97T+TaFfIwKK24ZGkE8AkbNSUAh/mzwpgtYwHb48YufC9s7sv5JIVUtT/6bFLuMVmhx6J98+dL2Pb+J/wLsNwn8WHzUehr6Y7xTRJjDkI/3Bwr5zkwBLJdHANsg5idD2ELbcSe/Tf+YBDxXfaoPq9KovRYDr9F+ioncA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=meAleQXc; arc=none smtp.client-ip=198.175.65.17 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="meAleQXc" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1787077839; x=1818613839; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=OifyDmtF7aGLxK+GIfjGGWqID3Pft2TdvjfmPOg6RNw=; b=meAleQXc1UPmllyzoUvxgfhnthZaiiVl6iorKi6hqF63NDX2ttgipTgk Lu9hmMqwAYi+DrrNc3oKhg7CO4DGVEfcLtOXwkbpC9CZLSjWa8qMCAWna 83SezyWjo2ki/H6N7qGNnWn/ZREkroOxAHcDMobqO5hFW+LLs4kjDVnXV PhWriNcgjvkXnZfOPgixDuAL/ql+xwaRTNQ2DeCgT84aq1QnNYbGiY7cA el8cX5042k9fi0mqO/bPTA+f2OoaxSzmjkBglgeNPxhXOll4aWVDON2qT ax+AtLsoZFHL6StdJeaPm1ikaxyFh1ibxaprb9afhdMLRjAoUyeBzSxGx Q==; X-CSE-ConnectionGUID: agi8pMUERaCDq9oOlp94Hg== X-CSE-MsgGUID: Z8W40p3cRr+R04ltsl1tjA== X-IronPort-AV: E=McAfee;i="6800,10657,11879"; a="87600303" X-IronPort-AV: E=Sophos;i="6.25,230,1779174000"; d="scan'208";a="87600303" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Aug 2026 11:30:34 -0700 X-CSE-ConnectionGUID: KcavLuuBTmWlqIilQCgbEw== X-CSE-MsgGUID: kXSwHcT+RJmOCpjnj6WzoA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,230,1779174000"; d="scan'208";a="262032100" Received: from soc-cp83kr3.clients.intel.com (HELO [10.122.185.5]) ([10.122.185.5]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Aug 2026 11:30:33 -0700 Message-ID: Date: Tue, 18 Aug 2026 13:30:32 -0500 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 v8 7/8] KVM: x86/pmu: Emulate RDPMC on performance metrics To: Andi Kleen Cc: Sean Christopherson , Paolo Bonzini , kvm@vger.kernel.org, Jim Mattson , linux-kernel@vger.kernel.org, Mingwei Zhang , Das Sandipan , Shukla Manali , Dapeng Mi , Xudong Hao References: <20260817183143.226156-1-zide.chen@intel.com> <20260817183143.226156-8-zide.chen@intel.com> Content-Language: en-US From: "Chen, Zide" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/18/2026 12:41 PM, Andi Kleen wrote: > On Mon, Aug 17, 2026 at 11:31:41AM -0700, Zide Chen wrote: >> If the host has the PERF_METRICS capability but it's not present on >> the guest, RDPMC interception must be enabled and KVM should inject >> an #GP when the guest attempts a PERF_METRICS RDPMC. >> >> If the guest has PERF_METRICS but RDPMC interception is enabled for >> other reasons, KVM needs to emulate RDPMC with type 0x2000. >> >> For simplicity, Metrics Clear Mode is not supported. > > But is the bit cleared in PERF_CAPABILITIES? And would > the enable bit fault? Currently KVM doesn't advertise IA32_PERF_CAPABILITIES.RDPMC_METRICS_CLEAR[19]. > It would be better to just support it, metrics clear is actually useful. Sure, I'll add it. > -Andi