From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.7]) (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 6D3483EC6A8; Thu, 27 Aug 2026 22:48:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.7 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787870899; cv=none; b=Ho4wV8KgXEYYu0Ttxu1Z+EHyM1G70QFL+/o7tetNvM+jwQP1T5JunPL9P7rVOAQFULR4ERSRcA/QntaGSgDFDR74LXGV5OlXN+sc8NXJ8a9I+/Eqy04GVcsIDOAFtqcwhycJFGL4bvKVQamANTtIwPg2f2GOA92yigQyeLMlTzY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787870899; c=relaxed/simple; bh=cbwhMbiNXnhJwK4d0wZATxl2UZxV+zXxGFUqJiZDN1Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nGuKqyDOBhGCbY1LM/0zX6KL3oO7iciKox0luMJqKq60auvIt3kyXp8TiPgJZQIkeNZ64yknbdBzkiOU0z3TZjVbBot8r+dYzz/XXBl4ZmQYa7HipVXo7I3yPUxxsE6kGReY7ekfy3QkvEHJnyPO+K69oEnpbk24m9gfJ16buGg= 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=Fbx3TMtH; arc=none smtp.client-ip=192.198.163.7 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="Fbx3TMtH" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1787870897; x=1819406897; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=cbwhMbiNXnhJwK4d0wZATxl2UZxV+zXxGFUqJiZDN1Q=; b=Fbx3TMtHrTGWYJ6yLW3Kb5qkZkiB01opTYTk8sgEDbsqPdRSDvtqZ6dS nrpOsJNH5nJAuqglOAWUGQ9juxkyVV/0S/ocD+pABnRB+yBFuiOkKUBle 99UjGJ3xgWCdoIn6329GqRK8tnHbP8Sy/Ooid+kNmecjNPOQ7pgFE27In U7Aj74vOul5XlUNMoV250nCuiSbVCcROAEr+9A7SvKj39uWLoYsc9kOsU ppmYOIkA1kNIPKWzxO5IvJzE+eIRFylIEY3A2IIc8uioNQNp5JNDw5ykI L2nWljaIiTmAzdor9QKgdqq4LeXHZZ5rSRM1oRKSPZQN8tmBHDCdBhovQ w==; X-CSE-ConnectionGUID: 90EkvnIlRDCW60lNydkJxQ== X-CSE-MsgGUID: zqaIvz6wR92y6Ly3EUKXVQ== X-IronPort-AV: E=McAfee;i="6800,10657,11888"; a="113914901" X-IronPort-AV: E=Sophos;i="6.25,247,1779174000"; d="scan'208";a="113914901" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by fmvoesa101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Aug 2026 15:48:10 -0700 X-CSE-ConnectionGUID: x9mAtXTOST69SwRg52g8Dg== X-CSE-MsgGUID: LuR7EEEYSpKhWxtuISnZKw== X-ExtLoop1: 1 Received: from 9cc2c43eec6b.jf.intel.com ([10.54.77.29]) by fmviesa003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Aug 2026 15:48:10 -0700 From: Zide Chen To: Sean Christopherson , Paolo Bonzini , Peter Zijlstra Cc: kvm@vger.kernel.org, Andi Kleen , Jim Mattson , Stephane Eranian , linux-kernel@vger.kernel.org, Mingwei Zhang , Zide Chen , Das Sandipan , Shukla Manali , Dapeng Mi , Xudong Hao Subject: [PATCH v2 15/16] KVM: x86/pmu: Advertise PerfMon version 5 on Intel hosts Date: Thu, 27 Aug 2026 15:37:54 -0700 Message-ID: <20260827223755.143247-16-zide.chen@intel.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260827223755.143247-1-zide.chen@intel.com> References: <20260827223755.143247-1-zide.chen@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Dapeng Mi KVM currently caps the guest PerfMon version at 2 for all Intel platforms. Now that KVM emulates the basic architectural PMU features introduced in PerfMon versions 3 through 5, raise the guest PerfMon version to 5. Features that require additional emulation support, e.g. architectural LBR will be enabled separately. PerfMon versions 3 and 4 continue to be exposed as version 2 because KVM cannot safely virtualize AnyThread due to cross-VM information leakage. PerfMon v5 is supported because it provides the AnyThread-deprecated capability, allowing KVM to indicate that AnyThread is deprecated. When enable_mediated_pmu is disabled or in the non-Intel paths, KVM retains the existing cap of version 2. Signed-off-by: Dapeng Mi Signed-off-by: Zide Chen --- v2: - Cap vPMU v3/v4 to v2, as AnyThread cannot be safely virtualized. (Sashiko) --- arch/x86/kvm/pmu.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 4cb7c796daac..1a7be7d73b62 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -175,7 +175,21 @@ void kvm_init_pmu_capability(struct kvm_pmu_ops *pmu_ops) } memcpy(&kvm_pmu_cap, &kvm_host_pmu, sizeof(kvm_host_pmu)); - kvm_pmu_cap.version = min(kvm_pmu_cap.version, 2); + + if (is_intel && enable_mediated_pmu) { + kvm_pmu_cap.version = min(kvm_pmu_cap.version, 5); + + /* + * PMU v3/v4 has AnyThread support, which KVM cannot safely + * virtualize. Expose PMU v2 instead of advertising a partially + * functional PMU v3/v4 to guests. + */ + if (kvm_pmu_cap.version == 3 || kvm_pmu_cap.version == 4) + kvm_pmu_cap.version = 2; + } else { + kvm_pmu_cap.version = min(kvm_pmu_cap.version, 2); + } + kvm_pmu_cap.cntr_mask64 &= GENMASK_ULL(pmu_ops->MAX_NR_GP_COUNTERS - 1, 0); kvm_pmu_cap.fixed_cntr_mask64 &= -- 2.55.0