From patchwork Thu Jun 13 23:36:23 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Salil Mehta X-Patchwork-Id: 13697634 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 CF89BC27C75 for ; Thu, 13 Jun 2024 23:42:56 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sHu5n-0005yG-G4; Thu, 13 Jun 2024 19:42:55 -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 1sHu5l-0005o5-2u; Thu, 13 Jun 2024 19:42:53 -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 1sHu5j-0003zc-5d; Thu, 13 Jun 2024 19:42:52 -0400 Received: from mail.maildlp.com (unknown [172.18.186.31]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4W0f921SBRz6K62D; Fri, 14 Jun 2024 07:42:46 +0800 (CST) Received: from lhrpeml500001.china.huawei.com (unknown [7.191.163.213]) by mail.maildlp.com (Postfix) with ESMTPS id 10EC3140594; Fri, 14 Jun 2024 07:42:49 +0800 (CST) Received: from 00293818-MRGF.china.huawei.com (10.195.245.24) by lhrpeml500001.china.huawei.com (7.191.163.213) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Fri, 14 Jun 2024 00:42:26 +0100 To: , , CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH RFC V3 13/29] arm/virt: Make ARM vCPU *present* status ACPI *persistent* Date: Fri, 14 Jun 2024 00:36:23 +0100 Message-ID: <20240613233639.202896-14-salil.mehta@huawei.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240613233639.202896-1-salil.mehta@huawei.com> References: <20240613233639.202896-1-salil.mehta@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.195.245.24] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To lhrpeml500001.china.huawei.com (7.191.163.213) 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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 ARM arch does not allow CPUs presence to be changed [1] after kernel has booted. Hence, firmware/ACPI/Qemu must ensure persistent view of the vCPUs to the Guest kernel even when they are not present in the QoM i.e. are unplugged or are yet-to-be-plugged References: [1] Check comment 5 in the bugzilla entry Link: https://bugzilla.tianocore.org/show_bug.cgi?id=4481#c5 Signed-off-by: Salil Mehta --- cpu-common.c | 6 ++++++ hw/arm/virt.c | 7 +++++++ include/hw/core/cpu.h | 21 +++++++++++++++++++++ 3 files changed, 34 insertions(+) diff --git a/cpu-common.c b/cpu-common.c index 49d2a50835..e4b4dee99a 100644 --- a/cpu-common.c +++ b/cpu-common.c @@ -128,6 +128,12 @@ bool qemu_enabled_cpu(CPUState *cpu) return cpu && !cpu->disabled; } +bool qemu_persistent_cpu(CPUState *cpu) +{ + /* cpu state can be faked to the guest via acpi */ + return cpu && cpu->acpi_persistent; +} + uint64_t qemu_get_cpu_archid(int cpu_index) { MachineState *ms = MACHINE(qdev_get_machine()); diff --git a/hw/arm/virt.c b/hw/arm/virt.c index 5f98162587..9d33f30a6a 100644 --- a/hw/arm/virt.c +++ b/hw/arm/virt.c @@ -3016,6 +3016,13 @@ static void virt_cpu_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, return; } virt_cpu_set_properties(OBJECT(cs), cpu_slot, errp); + + /* + * To give persistent presence view of vCPUs to the guest, ACPI might need + * to fake the presence of the vCPUs to the guest but keep them disabled. + * This shall be used during the init of ACPI Hotplug state and hot-unplug + */ + cs->acpi_persistent = true; } static void virt_cpu_plug(HotplugHandler *hotplug_dev, DeviceState *dev, diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h index 62e68611c0..e13e542177 100644 --- a/include/hw/core/cpu.h +++ b/include/hw/core/cpu.h @@ -540,6 +540,14 @@ struct CPUState { * every CPUState is enabled across all architectures. */ bool disabled; + /* + * On certain architectures, to provide a persistent view of the 'presence' + * of vCPUs to the guest, ACPI might need to fake the 'presence' of the + * vCPUs but keep them ACPI-disabled for the guest. This is achieved by + * returning `_STA.PRES=True` and `_STA.Ena=False` for the unplugged vCPUs + * in QEMU QoM. + */ + bool acpi_persistent; /* TODO Move common fields from CPUArchState here. */ int cpu_index; @@ -959,6 +967,19 @@ bool qemu_present_cpu(CPUState *cpu); */ bool qemu_enabled_cpu(CPUState *cpu); +/** + * qemu_persistent_cpu: + * @cpu: The vCPU to check + * + * Checks if the vCPU state should always be reflected as *present* via ACPI + * to the Guest. By default, this is False on all architectures and has to be + * explicity set during initialization. + * + * Returns: True if it is ACPI 'persistent' CPU + * + */ +bool qemu_persistent_cpu(CPUState *cpu); + /** * qemu_get_cpu_archid: * @cpu_index: possible vCPU for which arch-id needs to be retreived