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=-17.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 B823EC43381 for ; Wed, 6 Jan 2021 20:34:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8E4B923132 for ; Wed, 6 Jan 2021 20:34:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727347AbhAFUej (ORCPT ); Wed, 6 Jan 2021 15:34:39 -0500 Received: from mail-wm1-f54.google.com ([209.85.128.54]:37424 "EHLO mail-wm1-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727217AbhAFUei (ORCPT ); Wed, 6 Jan 2021 15:34:38 -0500 Received: by mail-wm1-f54.google.com with SMTP id q75so3726607wme.2; Wed, 06 Jan 2021 12:34:21 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=m0hrJnkhTHI8MFmITTywSTXP99AQKzpVEujA7fFIdZs=; b=UsaRr6NsevlKvsPxn5G2Hxd05+2UM25KMYDE9iygmclYMYtqcP4Un+T4xtjP7CSlHS rzJ0T6WTdMK/MMWv1kiZw9Yi6cz85r9aQYAYDRyoqV7qwqQl6eFxH0xYDI9zKYXdrN6v Nq0QS9YjruCIJ8h8TM5C9GWYyVvCM6dBXzDXLLhNXwPizxPQHRDmjn0GTlGkj85W3Z72 HZVsh9OzaRlOhalNWUBWrIxp8XD8MKfyTJSFIaZJAKwhGA+aqba+2ah/7nNpGkFw+rJB aBD5L8D/JeIk4SjmDFD6HJKRcIEISer2O+X0Qn0Hgz+wMXerOrU2Nwxc4uN3xxplTNs/ ecrA== X-Gm-Message-State: AOAM531/GH8OOzjpobrB0IVNfJhSYcbaJKFGS71Ay1pQ44rqSESXU6nU 7GggC8FOcP5MpQC1XlBhquwQpHhRf0Q= X-Google-Smtp-Source: ABdhPJwYr1YnHm+3rYQk3GIK8uU0NvkcTw+XgzktXprvWYFh8zP1kRWd97ttGDXw5cF0VCboKzzVSg== X-Received: by 2002:a05:600c:220b:: with SMTP id z11mr5314943wml.64.1609965235793; Wed, 06 Jan 2021 12:33:55 -0800 (PST) Received: from liuwe-devbox-debian-v2.j3c5onc20sse1dnehy4noqpfcg.zx.internal.cloudapp.net ([51.145.34.42]) by smtp.gmail.com with ESMTPSA id u9sm4499456wmb.32.2021.01.06.12.33.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 Jan 2021 12:33:55 -0800 (PST) From: Wei Liu To: Linux on Hyper-V List Cc: virtualization@lists.linux-foundation.org, Linux Kernel List , Michael Kelley , Vineeth Pillai , Sunil Muthuswamy , Nuno Das Neves , Wei Liu , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)), "H. Peter Anvin" Subject: [PATCH v4 02/17] x86/hyperv: detect if Linux is the root partition Date: Wed, 6 Jan 2021 20:33:35 +0000 Message-Id: <20210106203350.14568-3-wei.liu@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210106203350.14568-1-wei.liu@kernel.org> References: <20210106203350.14568-1-wei.liu@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For now we can use the privilege flag to check. Stash the value to be used later. Put in a bunch of defines for future use when we want to have more fine-grained detection. Signed-off-by: Wei Liu --- v3: move hv_root_partition to mshyperv.c --- arch/x86/include/asm/hyperv-tlfs.h | 10 ++++++++++ arch/x86/include/asm/mshyperv.h | 2 ++ arch/x86/kernel/cpu/mshyperv.c | 20 ++++++++++++++++++++ 3 files changed, 32 insertions(+) diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h index 6bf42aed387e..204010350604 100644 --- a/arch/x86/include/asm/hyperv-tlfs.h +++ b/arch/x86/include/asm/hyperv-tlfs.h @@ -21,6 +21,7 @@ #define HYPERV_CPUID_FEATURES 0x40000003 #define HYPERV_CPUID_ENLIGHTMENT_INFO 0x40000004 #define HYPERV_CPUID_IMPLEMENT_LIMITS 0x40000005 +#define HYPERV_CPUID_CPU_MANAGEMENT_FEATURES 0x40000007 #define HYPERV_CPUID_NESTED_FEATURES 0x4000000A #define HYPERV_CPUID_VIRT_STACK_INTERFACE 0x40000081 @@ -110,6 +111,15 @@ /* Recommend using enlightened VMCS */ #define HV_X64_ENLIGHTENED_VMCS_RECOMMENDED BIT(14) +/* + * CPU management features identification. + * These are HYPERV_CPUID_CPU_MANAGEMENT_FEATURES.EAX bits. + */ +#define HV_X64_START_LOGICAL_PROCESSOR BIT(0) +#define HV_X64_CREATE_ROOT_VIRTUAL_PROCESSOR BIT(1) +#define HV_X64_PERFORMANCE_COUNTER_SYNC BIT(2) +#define HV_X64_RESERVED_IDENTITY_BIT BIT(31) + /* * Virtual processor will never share a physical core with another virtual * processor, except for virtual processors that are reported as sibling SMT diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index ffc289992d1b..ac2b0d110f03 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -237,6 +237,8 @@ int hyperv_fill_flush_guest_mapping_list( struct hv_guest_mapping_flush_list *flush, u64 start_gfn, u64 end_gfn); +extern bool hv_root_partition; + #ifdef CONFIG_X86_64 void hv_apic_init(void); void __init hv_init_spinlocks(void); diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index f628e3dc150f..c376d191a260 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -32,6 +32,10 @@ #include #include +/* Is Linux running as the root partition? */ +bool hv_root_partition; +EXPORT_SYMBOL_GPL(hv_root_partition); + struct ms_hyperv_info ms_hyperv; EXPORT_SYMBOL_GPL(ms_hyperv); @@ -237,6 +241,22 @@ static void __init ms_hyperv_init_platform(void) pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n", ms_hyperv.max_vp_index, ms_hyperv.max_lp_index); + /* + * Check CPU management privilege. + * + * To mirror what Windows does we should extract CPU management + * features and use the ReservedIdentityBit to detect if Linux is the + * root partition. But that requires negotiating CPU management + * interface (a process to be finalized). + * + * For now, use the privilege flag as the indicator for running as + * root. + */ + if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_CPU_MANAGEMENT) { + hv_root_partition = true; + pr_info("Hyper-V: running as root partition\n"); + } + /* * Extract host information. */ -- 2.20.1