From patchwork Thu Nov 24 05:53:02 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jinank Jain X-Patchwork-Id: 25314 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:f944:0:0:0:0:0 with SMTP id q4csp3210695wrr; Wed, 23 Nov 2022 21:54:34 -0800 (PST) X-Google-Smtp-Source: AA0mqf68iNNBg0wSQY9w68RhDdLxiatb8wK7k9f7p6i0yAQ07aW+jD7apUcceLnAERY8E6iFL87P X-Received: by 2002:a17:907:a803:b0:7ae:bfeb:f484 with SMTP id vo3-20020a170907a80300b007aebfebf484mr2625252ejc.174.1669269274643; Wed, 23 Nov 2022 21:54:34 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1669269274; cv=none; d=google.com; s=arc-20160816; b=cfz5TzB/Y4sMb3G195vN3NOsCJMCwSHptD8nxnf5gY70u/vLjJ1BcD6qpsRDwFYd3J vjt+WEAEImszswxuuntzQ4FHlYkg6h9IUG3yZ2yCDM4bZxwpVXIkcY8X1g9750m/Fwub obCe1KIzPP3Cv5ShObirIhwbaBYE9loyCSEaItPUZzNT4gsA42VSPvC9kovdfN2Ujlkx hUzrnUL85stEj+rVGk3o0YKCBsEG8Ec61i4nXe9BApeZMjz0jNa3FDLRoTlH8BbsSRl2 lAqRxopNyJIcVFSNkQp4k0WNBh7Uw7K45Um/7ZG5JD0Puv1eVgOFcj3mPwRVHSSR0Hh0 aRMg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature:dkim-filter; bh=jZrfE3E4lxhGw+MvJUCDK70VJfmkQMf6oCsKZEKTHbw=; b=i59nSAvNvdM7FV+HZI+MNWzyMl5/YmLjUL35kD+2FnCSAPNbIoIrsON23D5NR73t+6 PfxvZSNCkYzS9sB2Ol/+ekkd8SPqF9XOnX1FzbaqoiPmNIDxfwvLcSx0BA2U9DvLNAyM AtCdr86ug98cU3Ytf7chHT0oMj7NJE0GyFclNdpdN7SdqNf+gbrYYMp/n3poyxaKpPUP OxKLV1fjy+WC8np6ZS/zMOJSo/6Wn4xkGgzX7db0ZXo5nX83a/yFNpQ0Dt9EAWXK1cya Z3ymxiPCmNXyGvDpLmuqf7VkFhHxBqDQ3sCIWtgQr3lWF69xR04wYct+1Gd4c5DZ4hU/ Bsfw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linux.microsoft.com header.s=default header.b=fsJkT7MQ; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linux.microsoft.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id u11-20020a50eacb000000b004687eebac58si200177edp.458.2022.11.23.21.54.11; Wed, 23 Nov 2022 21:54:34 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linux.microsoft.com header.s=default header.b=fsJkT7MQ; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linux.microsoft.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229491AbiKXFxX (ORCPT + 99 others); Thu, 24 Nov 2022 00:53:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34306 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229604AbiKXFxT (ORCPT ); Thu, 24 Nov 2022 00:53:19 -0500 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 970CD1EAC6; Wed, 23 Nov 2022 21:53:17 -0800 (PST) Received: from jinankjain-dranzer.zrrkmle5drku1h0apvxbr2u2ee.ix.internal.cloudapp.net (unknown [20.188.121.5]) by linux.microsoft.com (Postfix) with ESMTPSA id 2C4E820B83C2; Wed, 23 Nov 2022 21:53:13 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 2C4E820B83C2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1669269197; bh=jZrfE3E4lxhGw+MvJUCDK70VJfmkQMf6oCsKZEKTHbw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fsJkT7MQfC2MQvHCaG6nXp5pxlx9jSGzE5gYQO6E0D/dUmMI1oUaJkYe+jgfGBCQk LnTahLt4giB+5hU5n5TK46tXAlx6kN+SV9TzxWI9uIJRWbat9ssOUQIxYYczao2S0w +0+gmQN8s4tsyNggapI0anuKyCI053Qs43EjvXTY= From: Jinank Jain To: jinankjain@microsoft.com Cc: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, arnd@arndb.de, peterz@infradead.org, jpoimboe@kernel.org, jinankjain@linux.microsoft.com, seanjc@google.com, kirill.shutemov@linux.intel.com, ak@linux.intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, anrayabh@linux.microsoft.com, mikelley@microsoft.com Subject: [PATCH v5 1/5] x86/hyperv: Add support for detecting nested hypervisor Date: Thu, 24 Nov 2022 05:53:02 +0000 Message-Id: <08ab7aede41f2feb1cd8ac21d0ddd17e25b1d070.1669007822.git.jinankjain@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 X-Spam-Status: No, score=-19.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,ENV_AND_HDR_SPF_MATCH,RCVD_IN_DNSWL_MED, SPF_HELO_PASS,SPF_PASS,USER_IN_DEF_DKIM_WL,USER_IN_DEF_SPF_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1750355699297852774?= X-GMAIL-MSGID: =?utf-8?q?1750355699297852774?= When Linux runs as a root partition for Microsoft Hypervisor. It is possible to detect if it is running as nested hypervisor using hints exposed by mshv. While at it expose a new variable called hv_nested which can be used later for making decisions specific to nested use case. Signed-off-by: Jinank Jain --- arch/arm64/hyperv/mshyperv.c | 6 ++++++ arch/x86/include/asm/hyperv-tlfs.h | 3 +++ arch/x86/kernel/cpu/mshyperv.c | 7 +++++++ drivers/hv/hv_common.c | 7 +++++-- include/asm-generic/mshyperv.h | 1 + 5 files changed, 22 insertions(+), 2 deletions(-) diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c index a406454578f0..2024b19dc514 100644 --- a/arch/arm64/hyperv/mshyperv.c +++ b/arch/arm64/hyperv/mshyperv.c @@ -19,6 +19,9 @@ static bool hyperv_initialized; +/* Is Linux running on nested Microsoft Hypervisor */ +bool hv_nested; + static int __init hyperv_init(void) { struct hv_get_vp_registers_output result; @@ -63,6 +66,9 @@ static int __init hyperv_init(void) pr_info("Hyper-V: Host Build %d.%d.%d.%d-%d-%d\n", b >> 16, b & 0xFFFF, a, d & 0xFFFFFF, c, d >> 24); + /* ARM64 does not support nested virtualization */ + hv_nested = false; + ret = hv_common_init(); if (ret) return ret; diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h index 6d9368ea3701..58c03d18c235 100644 --- a/arch/x86/include/asm/hyperv-tlfs.h +++ b/arch/x86/include/asm/hyperv-tlfs.h @@ -114,6 +114,9 @@ /* Recommend using the newer ExProcessorMasks interface */ #define HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED BIT(11) +/* Indicates that the hypervisor is nested within a Hyper-V partition. */ +#define HV_X64_HYPERV_NESTED BIT(12) + /* Recommend using enlightened VMCS */ #define HV_X64_ENLIGHTENED_VMCS_RECOMMENDED BIT(14) diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 831613959a92..9a4204139490 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -37,6 +37,8 @@ /* Is Linux running as the root partition? */ bool hv_root_partition; +/* Is Linux running on nested Microsoft Hypervisor */ +bool hv_nested; struct ms_hyperv_info ms_hyperv; #if IS_ENABLED(CONFIG_HYPERV) @@ -301,6 +303,11 @@ static void __init ms_hyperv_init_platform(void) pr_info("Hyper-V: running as root partition\n"); } + if (ms_hyperv.hints & HV_X64_HYPERV_NESTED) { + hv_nested = true; + pr_info("Hyper-V: running on a nested hypervisor\n"); + } + /* * Extract host information. */ diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index ae68298c0dca..dcb336ce374f 100644 --- a/drivers/hv/hv_common.c +++ b/drivers/hv/hv_common.c @@ -25,8 +25,8 @@ #include /* - * hv_root_partition and ms_hyperv are defined here with other Hyper-V - * specific globals so they are shared across all architectures and are + * hv_root_partition, ms_hyperv and hv_nested are defined here with other + * Hyper-V specific globals so they are shared across all architectures and are * built only when CONFIG_HYPERV is defined. But on x86, * ms_hyperv_init_platform() is built even when CONFIG_HYPERV is not * defined, and it uses these two variables. So mark them as __weak @@ -36,6 +36,9 @@ bool __weak hv_root_partition; EXPORT_SYMBOL_GPL(hv_root_partition); +bool __weak hv_nested; +EXPORT_SYMBOL_GPL(hv_nested); + struct ms_hyperv_info __weak ms_hyperv; EXPORT_SYMBOL_GPL(ms_hyperv); diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h index bfb9eb9d7215..5df6e944e6a9 100644 --- a/include/asm-generic/mshyperv.h +++ b/include/asm-generic/mshyperv.h @@ -164,6 +164,7 @@ extern int vmbus_interrupt; extern int vmbus_irq; extern bool hv_root_partition; +extern bool hv_nested; #if IS_ENABLED(CONFIG_HYPERV) /*