From patchwork Tue Sep 26 10:36:54 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Salil Mehta X-Patchwork-Id: 13399072 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1949DE7D27B for ; Tue, 26 Sep 2023 10:39:22 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ql5TI-0007eg-5e; Tue, 26 Sep 2023 06:39:16 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ql5TE-0007IR-7V; Tue, 26 Sep 2023 06:39:12 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ql5TC-00022Z-62; Tue, 26 Sep 2023 06:39:11 -0400 Received: from lhrpeml500001.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Rvx1W66cbz6J7yR; Tue, 26 Sep 2023 18:34:07 +0800 (CST) Received: from A190218597.china.huawei.com (10.126.174.16) by lhrpeml500001.china.huawei.com (7.191.163.213) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Tue, 26 Sep 2023 11:38:48 +0100 To: , CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH RFC V2 37/37] hw/arm/virt: Expose cold-booted CPUs as MADT GICC Enabled Date: Tue, 26 Sep 2023 11:36:54 +0100 Message-ID: <20230926103654.34424-6-salil.mehta@huawei.com> X-Mailer: git-send-email 2.8.3 In-Reply-To: <20230926103654.34424-1-salil.mehta@huawei.com> References: <20230926100436.28284-1-salil.mehta@huawei.com> <20230926103654.34424-1-salil.mehta@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.126.174.16] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To lhrpeml500001.china.huawei.com (7.191.163.213) X-CFilter-Loop: Reflected Received-SPF: pass client-ip=185.176.79.56; envelope-from=salil.mehta@huawei.com; helo=frasgout.his.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: Salil Mehta X-Patchwork-Original-From: Salil Mehta via From: Salil Mehta Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Hotpluggable CPUs MUST be exposed as 'online-capable' as per the new change. But cold booted CPUs if made 'online-capable' during boot time might not get detected in the legacy OS. Hence, can cause compatibility problems. Original Change Link: https://bugzilla.tianocore.org/show_bug.cgi?id=3706 Specification change might take time and hence disabling the support of unplugging any cold booted CPUs to preserve the compatibility with legacy OS. Signed-off-by: Salil Mehta --- hw/arm/virt-acpi-build.c | 19 ++++++++++++++----- hw/arm/virt.c | 16 ++++++++++++++++ include/hw/core/cpu.h | 2 ++ 3 files changed, 32 insertions(+), 5 deletions(-) diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c index 377450dd16..879c83a337 100644 --- a/hw/arm/virt-acpi-build.c +++ b/hw/arm/virt-acpi-build.c @@ -710,17 +710,26 @@ static uint32_t virt_acpi_get_gicc_flags(CPUState *cpu) } /* - * ARM GIC CPU Interface can be 'online-capable' or 'enabled' at boot - * We MUST set 'online-capable' Bit for all hotpluggable CPUs except the - * first/boot CPU. Cold-booted CPUs without 'Id' can also be unplugged. - * Though as-of-now this is only used as a debugging feature. + * ARM GIC CPU Interface can be 'online-capable' or 'enabled' at boot. We + * MUST set 'online-capable' bit for all hotpluggable CPUs. + * Change Link: https://bugzilla.tianocore.org/show_bug.cgi?id=3706 * * UEFI ACPI Specification 6.5 * Section: 5.2.12.14. GIC CPU Interface (GICC) Structure * Table: 5.37 GICC CPU Interface Flags * Link: https://uefi.org/specs/ACPI/6.5 + * + * Cold-booted CPUs, except for the first/boot CPU, SHOULD be allowed to be + * hot(un)plug as well but for this to happen these MUST have + * 'online-capable' bit set. Later creates compatibility problem with legacy + * OS as it might ignore online-capable' bits during boot time and hence + * some CPUs might not get detected. To fix this MADT GIC CPU interface flag + * should be allowed to have both bits set i.e. 'online-capable' and + * 'Enabled' bits together. This change will require UEFI ACPI standard + * change. Till this happens exposing all cold-booted CPUs as 'enabled' only + * */ - return cpu && !cpu->cpu_index ? 1 : (1 << 3); + return cpu && cpu->cold_booted ? 1 : (1 << 3); } static void diff --git a/hw/arm/virt.c b/hw/arm/virt.c index e46f529801..3bfe9b9db3 100644 --- a/hw/arm/virt.c +++ b/hw/arm/virt.c @@ -3151,6 +3151,10 @@ static void virt_cpu_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, * This shall be used during the init of ACPI Hotplug state and hot-unplug */ cs->acpi_persistent = true; + + if (!dev->hotplugged) { + cs->cold_booted = true; + } } static void virt_cpu_plug(HotplugHandler *hotplug_dev, DeviceState *dev, @@ -3214,6 +3218,18 @@ static void virt_cpu_unplug_request(HotplugHandler *hotplug_dev, return; } + /* + * UEFI ACPI standard change is required to make both 'enabled' and the + * 'online-capable' bit co-exist instead of being mutually exclusive. + * check virt_acpi_get_gicc_flags() for more details. + * + * Disable the unplugging of cold-booted vCPUs as a temporary mitigation. + */ + if (cs->cold_booted) { + error_setg(errp, "Hot-unplug of cold-booted CPU not supported!"); + return; + } + if (cs->cpu_index == first_cpu->cpu_index) { error_setg(errp, "Boot CPU(id%d=%d:%d:%d:%d) hot-unplug not supported", first_cpu->cpu_index, cpu->socket_id, cpu->cluster_id, diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h index ffd815a0d8..f6b92a3285 100644 --- a/include/hw/core/cpu.h +++ b/include/hw/core/cpu.h @@ -441,6 +441,8 @@ struct CPUState { uint32_t can_do_io; int32_t exception_index; + bool cold_booted; + AccelCPUState *accel; /* shared by kvm, hax and hvf */ bool vcpu_dirty;