From patchwork Mon Feb 21 08:48:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 544818 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9E2DC433EF for ; Mon, 21 Feb 2022 09:27:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346438AbiBUJ16 (ORCPT ); Mon, 21 Feb 2022 04:27:58 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:50944 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349961AbiBUJ06 (ORCPT ); Mon, 21 Feb 2022 04:26:58 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 458E51EED6; Mon, 21 Feb 2022 01:10:57 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id B9A3CCE0E76; Mon, 21 Feb 2022 09:10:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D19C3C340EB; Mon, 21 Feb 2022 09:10:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1645434654; bh=bVSySelnyAeahJMSw/l2RKJiTmriqOVNBjS17DZ/XGc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mandIbmO1Lr6Zugza+AtLfPTYBdunbKBKD8ryGTwvD8c4FXYKMvYa4aYTBWSPmebV mNFkktlo9SrSwm1qm/hpqdXP8xiuO2jMU24R+QjYfVYo141R7DaUccCDrAlHPF8Xfh 68hmhhHCSz/IzIN08I2PtB9UKt/TKTFC0SFM4wdg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Beulich , Boris Ostrovsky , Juergen Gross , Sasha Levin Subject: [PATCH 5.15 051/196] x86/Xen: streamline (and fix) PV CPU enumeration Date: Mon, 21 Feb 2022 09:48:03 +0100 Message-Id: <20220221084932.647903781@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220221084930.872957717@linuxfoundation.org> References: <20220221084930.872957717@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jan Beulich [ Upstream commit e25a8d959992f61b64a58fc62fb7951dc6f31d1f ] This started out with me noticing that "dom0_max_vcpus=" with larger than the number of physical CPUs reported through ACPI tables would not bring up the "excess" vCPU-s. Addressing this is the primary purpose of the change; CPU maps handling is being tidied only as far as is necessary for the change here (with the effect of also avoiding the setting up of too much per-CPU infrastructure, i.e. for CPUs which can never come online). Noticing that xen_fill_possible_map() is called way too early, whereas xen_filter_cpu_maps() is called too late (after per-CPU areas were already set up), and further observing that each of the functions serves only one of Dom0 or DomU, it looked like it was better to simplify this. Use the .get_smp_config hook instead, uniformly for Dom0 and DomU. xen_fill_possible_map() can be dropped altogether, while xen_filter_cpu_maps() is re-purposed but not otherwise changed. Signed-off-by: Jan Beulich Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/r/2dbd5f0a-9859-ca2d-085e-a02f7166c610@suse.com Signed-off-by: Juergen Gross Signed-off-by: Sasha Levin --- arch/x86/xen/enlighten_pv.c | 4 ---- arch/x86/xen/smp_pv.c | 26 ++++++-------------------- 2 files changed, 6 insertions(+), 24 deletions(-) diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c index a7b7d674f5005..133ef31639df1 100644 --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -1364,10 +1364,6 @@ asmlinkage __visible void __init xen_start_kernel(void) xen_acpi_sleep_register(); - /* Avoid searching for BIOS MP tables */ - x86_init.mpparse.find_smp_config = x86_init_noop; - x86_init.mpparse.get_smp_config = x86_init_uint_noop; - xen_boot_params_init_edd(); #ifdef CONFIG_ACPI diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c index 7ed56c6075b0c..477c484eb202c 100644 --- a/arch/x86/xen/smp_pv.c +++ b/arch/x86/xen/smp_pv.c @@ -148,28 +148,12 @@ int xen_smp_intr_init_pv(unsigned int cpu) return rc; } -static void __init xen_fill_possible_map(void) -{ - int i, rc; - - if (xen_initial_domain()) - return; - - for (i = 0; i < nr_cpu_ids; i++) { - rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL); - if (rc >= 0) { - num_processors++; - set_cpu_possible(i, true); - } - } -} - -static void __init xen_filter_cpu_maps(void) +static void __init _get_smp_config(unsigned int early) { int i, rc; unsigned int subtract = 0; - if (!xen_initial_domain()) + if (early) return; num_processors = 0; @@ -210,7 +194,6 @@ static void __init xen_pv_smp_prepare_boot_cpu(void) * sure the old memory can be recycled. */ make_lowmem_page_readwrite(xen_initial_gdt); - xen_filter_cpu_maps(); xen_setup_vcpu_info_placement(); /* @@ -486,5 +469,8 @@ static const struct smp_ops xen_smp_ops __initconst = { void __init xen_smp_init(void) { smp_ops = xen_smp_ops; - xen_fill_possible_map(); + + /* Avoid searching for BIOS MP tables */ + x86_init.mpparse.find_smp_config = x86_init_noop; + x86_init.mpparse.get_smp_config = _get_smp_config; }