From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.10]) (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 549313396E9; Mon, 16 Mar 2026 05:12:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773637971; cv=none; b=Y7caw1o12Gc+ZKMh6ym88qZ/JwR2SsLZmGkuJmTq0LoXC48KHJha3mS+84uSH5tz6NIu4UL587YWOLVYZPza6Y0weNBc49HqmyOXw1wrqtp1DbYoObgfqhBUkuFHSAhWK7nuuUxpul2UPRauI7opEW+jL7q1omJdmNPNIvjd8hM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773637971; c=relaxed/simple; bh=IKMdcMgH+u2bjuAiJri0Q8fmMQlZhYYXZh93E5g++hY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=NOzC+YcHfezYDr1DMMH2LJdGUTIY3x9UZM/v5URZzZ89R5vGiypDZBA1TVgHxq4duaqmbf7CwBGs6XMM9AJuAgVWJC+9CZgNdfRBZFQxeSX8tA7NM+fdmBLVml5lZ5qSW+QiGuPJAMsR/Tz+8yO2CpVS8hGY8ItxSOmTmZeWXhE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=NOTQYk4O; arc=none smtp.client-ip=192.198.163.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass 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="NOTQYk4O" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1773637970; x=1805173970; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=IKMdcMgH+u2bjuAiJri0Q8fmMQlZhYYXZh93E5g++hY=; b=NOTQYk4OV1YN+Ts/6y7GM89BV1Fk4GhgRu+1MdCRbQPT2EllJCYHUgcF leFWBNY0OX7PbcaIRcqKsMdwkwJKAbGqQeSRh7lPCcUPoLLFWPslULbOf HPKYbIK8z4Qm0G8qmzAEyYGa8X2pAth0YDhqUyEFU51vtnRPEZEW0icTP 5UjcyfmXspx8d1SY8UarlTG25W+UGlNfDGEyUeEEHSHrWgfEZ5FDvIXGw su7TZVnNB0sX9qh9AQTR1A6aq5HFIzar+ueY7oDu4W/qHaaikdjtViI6/ HsmKyiqEjf6LDJO1lOCh01jJJL0Y8F0b/AoQvQVaXyXX4o6UD1Ir/Plgz A==; X-CSE-ConnectionGUID: jJ1o9wpOSre+UVvlp0dM5w== X-CSE-MsgGUID: Pgt/wH4lTOWYP0FqfHsh0Q== X-IronPort-AV: E=McAfee;i="6800,10657,11730"; a="86003463" X-IronPort-AV: E=Sophos;i="6.23,123,1770624000"; d="scan'208";a="86003463" Received: from orviesa004.jf.intel.com ([10.64.159.144]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Mar 2026 22:12:50 -0700 X-CSE-ConnectionGUID: v7jb1GZHSKywycg/194Kyg== X-CSE-MsgGUID: 0ctDSsNUTTOvsw+4s85pjg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,123,1770624000"; d="scan'208";a="226262462" Received: from spr.sh.intel.com ([10.112.229.196]) by orviesa004.jf.intel.com with ESMTP; 15 Mar 2026 22:12:47 -0700 From: Dapeng Mi To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Ian Rogers , Adrian Hunter , Alexander Shishkin , Andi Kleen , Eranian Stephane Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Dapeng Mi , Zide Chen , Falcon Thomas , Xudong Hao , Dapeng Mi Subject: [Patch v2 2/2] perf/x86: Update cap_user_rdpmc base on rdpmc user disable state Date: Mon, 16 Mar 2026 13:08:38 +0800 Message-Id: <20260316050838.3624051-2-dapeng1.mi@linux.intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260316050838.3624051-1-dapeng1.mi@linux.intel.com> References: <20260316050838.3624051-1-dapeng1.mi@linux.intel.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit After introducing the RDPMC user disable feature, user-space RDPMC may return 0 instead of the actual event count. This creates an inconsistency with cap_user_rdpmc, where cap_user_rdpmc is set, but user-space RDPMC only returns 0. To accurately represent the user-space RDPMC capability, update cap_user_rdpmc based on the RDPMC user disable state. If RDPMC user disable is enabled, cap_user_rdpmc is set to false, allowing user-space programs to fall back to the read() syscall to obtain the real event count. Since arch_perf_update_userpage() could be called for software events, enhance x86_pmu_has_rdpmc_user_disable() to only check the x86 PMUs. Fixes: 59af95e028d4 ("perf/x86/intel: Add support for rdpmc user disable feature") Signed-off-by: Dapeng Mi --- v2: Add is_x86_pmu() check before checking if rdpmc user disable feature is supported. v1: https://lore.kernel.org/all/20260311075201.2951073-2-dapeng1.mi@linux.intel.com/ arch/x86/events/core.c | 3 +++ arch/x86/events/perf_event.h | 5 +++-- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 66b1a873c395..34eda8813716 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2794,6 +2794,9 @@ void arch_perf_update_userpage(struct perf_event *event, userpg->cap_user_time_zero = 0; userpg->cap_user_rdpmc = !!(event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT); + if (x86_pmu_has_rdpmc_user_disable(event->pmu) && + event->hw.config & ARCH_PERFMON_EVENTSEL_RDPMC_USER_DISABLE) + userpg->cap_user_rdpmc = 0; userpg->pmc_width = x86_pmu.cntval_bits; if (!using_native_sched_clock() || !sched_clock_stable()) diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h index 025f67726ecc..307361b106d2 100644 --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -1351,8 +1351,9 @@ static inline u64 x86_pmu_get_event_config(struct perf_event *event) static inline bool x86_pmu_has_rdpmc_user_disable(struct pmu *pmu) { - return !!(hybrid(pmu, config_mask) & - ARCH_PERFMON_EVENTSEL_RDPMC_USER_DISABLE); + return is_x86_pmu(pmu) && + (hybrid(pmu, config_mask) & + ARCH_PERFMON_EVENTSEL_RDPMC_USER_DISABLE); } extern struct event_constraint emptyconstraint; -- 2.34.1