From nobody Sun Feb 8 09:22:25 2026 Received: from mx0.riseup.net (mx0.riseup.net [198.252.153.6]) (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 7DFE0204F9B for ; Mon, 2 Dec 2024 14:53:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.252.153.6 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733151204; cv=none; b=tDxsSDbVE5TtMBmK7ixvyndzOtPR+AjvLXsAvPk0YMMX7wAj+XcWZBSdwJk89I5s2ah+qBrDLHGKFTFTn7Z4m3KQFmg9xMg6LTOjNgObZXrKgSyEHkEeemG/n14oaCGXM8iy3+Ey/pA05skRrtTx05msCuNnMvyKSPmjiQB2/vk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733151204; c=relaxed/simple; bh=jXQjIU1H3A9YIpgYmGkC0szjgftkkNkV8mxkIgvczQA=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=MwPjNdOwiTLy+fVgwAwdXlBcfeq1dCrSjoolI5kcbb0Ez9Tqd6pnSqS3czIWNlHwI3VtwXpVm/SQM3j9gSN7dv5patv7gp3ZeY2P4SeSghUrcVNK/CZGe60IdfMxb2116ulOtmZM3xXiGU072cU7GOOYAJFyKmSjwjeoP52+sfI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=riseup.net; spf=pass smtp.mailfrom=riseup.net; dkim=pass (1024-bit key) header.d=riseup.net header.i=@riseup.net header.b=L/RIxXhi; arc=none smtp.client-ip=198.252.153.6 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=riseup.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=riseup.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=riseup.net header.i=@riseup.net header.b="L/RIxXhi" Received: from fews02-sea.riseup.net (fews02-sea-pn.riseup.net [10.0.1.112]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx0.riseup.net (Postfix) with ESMTPS id 4Y26Gh25lZz9s6v; Mon, 2 Dec 2024 14:53:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=riseup.net; s=squak; t=1733151196; bh=jXQjIU1H3A9YIpgYmGkC0szjgftkkNkV8mxkIgvczQA=; h=From:To:Cc:Subject:Date:From; b=L/RIxXhifLC2dnobmefkZYY44RekxXiGY9ZR/qE+21a3kxetjoEl0HFBJ25R61SK8 gW2OqWzsvcZbZm35hwIt6X+nveYfAElnGmgT6ABpW/DmOfbh7GyeXoyRORLV77kUXA mqmERVKUDLewqYtQTLTwrLGY9q3rXojiir862P9E= X-Riseup-User-ID: CDF788113BB231E3723F47D744AD551ADC7B626B659682C1C71785E4A78254B9 Received: from [127.0.0.1] (localhost [127.0.0.1]) by fews02-sea.riseup.net (Postfix) with ESMTPSA id 4Y26Gf2N5TzFtSF; Mon, 2 Dec 2024 14:53:14 +0000 (UTC) From: Fernando Fernandez Mancera To: linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, x86@kernel.org, Fernando Fernandez Mancera Subject: [PATCH v2] x86/cpu/topology: remove limit of CPUs due to noapic on x86 Date: Mon, 2 Dec 2024 14:52:34 +0000 Message-ID: <20241202145243.1228-1-ffmancera@riseup.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" On x86 the command line parameter "noapic" should not limit the number of possible CPUs, as it only limits the use of IRQ sharing or device IRQ remapping. This restores the behavior previous to the rework of possible CPUs management. Fixes: 7c0edad3643f ("x86/cpu/topology: Rework possible CPU management") Signed-off-by: Fernando Fernandez Mancera --- arch/x86/kernel/cpu/topology.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c index 621a151ccf7d..b21f28f6a8a8 100644 --- a/arch/x86/kernel/cpu/topology.c +++ b/arch/x86/kernel/cpu/topology.c @@ -428,8 +428,8 @@ void __init topology_apply_cmdline_limits_early(void) { unsigned int possible =3D nr_cpu_ids; =20 - /* 'maxcpus=3D0' 'nosmp' 'nolapic' 'disableapic' 'noapic' */ - if (!setup_max_cpus || ioapic_is_disabled || apic_is_disabled) + /* 'maxcpus=3D0' 'nosmp' 'nolapic' 'disableapic' */ + if (!setup_max_cpus || apic_is_disabled) possible =3D 1; =20 /* 'possible_cpus=3DN' */ @@ -443,8 +443,9 @@ void __init topology_apply_cmdline_limits_early(void) =20 static __init bool restrict_to_up(void) { - if (!smp_found_config || ioapic_is_disabled) + if (!smp_found_config) return true; + /* * XEN PV is special as it does not advertise the local APIC * properly, but provides a fake topology for it so that the --=20 2.47.1