From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E5039C432BE for ; Mon, 2 Aug 2021 16:26:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B94B960FC0 for ; Mon, 2 Aug 2021 16:26:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230139AbhHBQ0i (ORCPT ); Mon, 2 Aug 2021 12:26:38 -0400 Received: from foss.arm.com ([217.140.110.172]:38366 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230224AbhHBQ0i (ORCPT ); Mon, 2 Aug 2021 12:26:38 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 52BBE11D4; Mon, 2 Aug 2021 09:26:28 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [10.57.10.176]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 607AB3F66F; Mon, 2 Aug 2021 09:26:26 -0700 (PDT) Date: Mon, 2 Aug 2021 17:26:23 +0100 From: Mark Rutland To: Michael Kelley Cc: will@kernel.org, catalin.marinas@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-efi@vger.kernel.org, wei.liu@kernel.org, kys@microsoft.com, sthemmin@microsoft.com, ardb@kernel.org Subject: Re: [PATCH v11 3/5] arm64: hyperv: Initialize hypervisor on boot Message-ID: <20210802162623.GC59710@C02TD0UTHF1T.local> References: <1626793023-13830-1-git-send-email-mikelley@microsoft.com> <1626793023-13830-4-git-send-email-mikelley@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1626793023-13830-4-git-send-email-mikelley@microsoft.com> Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Tue, Jul 20, 2021 at 07:57:01AM -0700, Michael Kelley wrote: > Add ARM64-specific code to initialize the Hyper-V > hypervisor when booting as a guest VM. > > This code is built only when CONFIG_HYPERV is enabled. > > Signed-off-by: Michael Kelley > --- > arch/arm64/hyperv/Makefile | 2 +- > arch/arm64/hyperv/mshyperv.c | 83 ++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 84 insertions(+), 1 deletion(-) > create mode 100644 arch/arm64/hyperv/mshyperv.c > > diff --git a/arch/arm64/hyperv/Makefile b/arch/arm64/hyperv/Makefile > index 1697d30..87c31c0 100644 > --- a/arch/arm64/hyperv/Makefile > +++ b/arch/arm64/hyperv/Makefile > @@ -1,2 +1,2 @@ > # SPDX-License-Identifier: GPL-2.0 > -obj-y := hv_core.o > +obj-y := hv_core.o mshyperv.o > diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c > new file mode 100644 > index 0000000..2811fd0 > --- /dev/null > +++ b/arch/arm64/hyperv/mshyperv.c > @@ -0,0 +1,83 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +/* > + * Core routines for interacting with Microsoft's Hyper-V hypervisor, > + * including hypervisor initialization. > + * > + * Copyright (C) 2021, Microsoft, Inc. > + * > + * Author : Michael Kelley > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +static bool hyperv_initialized; > + > +static int __init hyperv_init(void) > +{ > + struct hv_get_vp_registers_output result; > + u32 a, b, c, d; > + u64 guest_id; > + int ret; As Marc suggests, before looking at the FADT, you need something like: /* * Hyper-V VMs always have ACPI. */ if (acpi_disabled) return 0; ... where `acpi_disabled` is defined in (or via its includes), so you don't need to include any additional headers. > + > + /* > + * If we're in a VM on Hyper-V, the ACPI hypervisor_id field will > + * have the string "MsHyperV". > + */ > + if (strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8)) > + return -EINVAL; As Marc suggests, it's no an error for a platform to not have Hyper-V, so returning 0 in tihs case would be preferable. Otherwise this looks fine to me. Thanks, Mark. > + > + /* Setup the guest I[D */ > + guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0); > + hv_set_vpreg(HV_REGISTER_GUEST_OSID, guest_id); > + > + /* Get the features and hints from Hyper-V */ > + hv_get_vpreg_128(HV_REGISTER_FEATURES, &result); > + ms_hyperv.features = result.as32.a; > + ms_hyperv.priv_high = result.as32.b; > + ms_hyperv.misc_features = result.as32.c; > + > + hv_get_vpreg_128(HV_REGISTER_ENLIGHTENMENTS, &result); > + ms_hyperv.hints = result.as32.a; > + > + pr_info("Hyper-V: privilege flags low 0x%x, high 0x%x, hints 0x%x, misc 0x%x\n", > + ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints, > + ms_hyperv.misc_features); > + > + /* Get information about the Hyper-V host version */ > + hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION, &result); > + a = result.as32.a; > + b = result.as32.b; > + c = result.as32.c; > + d = result.as32.d; > + pr_info("Hyper-V: Host Build %d.%d.%d.%d-%d-%d\n", > + b >> 16, b & 0xFFFF, a, d & 0xFFFFFF, c, d >> 24); > + > + ret = hv_common_init(); > + if (ret) > + return ret; > + > + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm64/hyperv_init:online", > + hv_common_cpu_init, hv_common_cpu_die); > + if (ret < 0) { > + hv_common_free(); > + return ret; > + } > + > + hyperv_initialized = true; > + return 0; > +} > + > +early_initcall(hyperv_init); > + > +bool hv_is_hyperv_initialized(void) > +{ > + return hyperv_initialized; > +} > +EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized); > -- > 1.8.3.1 >