From patchwork Tue Nov 5 06:24:08 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiaoyao Li X-Patchwork-Id: 13862495 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 0C149D1CA38 for ; Tue, 5 Nov 2024 06:48:41 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1t8DHK-0006hy-T9; Tue, 05 Nov 2024 01:43:02 -0500 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 1t8DFs-0003vI-8P for qemu-devel@nongnu.org; Tue, 05 Nov 2024 01:41:32 -0500 Received: from mgamail.intel.com ([198.175.65.18]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1t8DFG-0001vj-Pq for qemu-devel@nongnu.org; Tue, 05 Nov 2024 01:41:05 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1730788855; x=1762324855; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=prNelkC3OOqKiNVm+vMpEf1u/DtP+lyJhK2V/YRgjzw=; b=Ak1d0aKZXlTgypm4kR0Opy8p+rbc1xZ7r6JUobhQTQzc77u4WSRRv2RB d+ZW455y32Vqjzi/cNsFzZRM3UeJgJlu6Y7KrMnigj/Ufc4EVc4huI0EE y04F8cnq/kHTyo2N1tRTpNGf4A5E6r/HpUizpxUKXTvi3pbTzBwBK8YTu ivqItQ0LCR8a+8Twl/LFfV12Q7nIuIk3h3Gj/JqPhbXiPjucfa5G7Gve5 HU2p2Y8I5KiqvV5VY+j8RV02nCSUxf+NzBS5dxOG61fDTg4rkvVzwlij5 eBBQEru03KePVmjk+0rSwzAH60rcot079iBSDCXNIqffjIPSaO0jxYNvU g==; X-CSE-ConnectionGUID: DPFZyhcfQ0CrxUNlTqPJeg== X-CSE-MsgGUID: X164P7OXTJ6R+YSw8iQTQQ== X-IronPort-AV: E=McAfee;i="6700,10204,11222"; a="30689973" X-IronPort-AV: E=Sophos;i="6.11,199,1725346800"; d="scan'208";a="30689973" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by orvoesa110.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Nov 2024 22:40:39 -0800 X-CSE-ConnectionGUID: WC4TK0djRPSDZtiizpWwBg== X-CSE-MsgGUID: +YDffLFqRz2Vf56nozSFLA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.11,259,1725346800"; d="scan'208";a="83990158" Received: from lxy-clx-4s.sh.intel.com ([10.239.48.52]) by fmviesa009.fm.intel.com with ESMTP; 04 Nov 2024 22:40:35 -0800 From: Xiaoyao Li To: Paolo Bonzini , Riku Voipio , Richard Henderson , Zhao Liu , "Michael S. Tsirkin" , Marcel Apfelbaum , Igor Mammedov , Ani Sinha Cc: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Yanan Wang , Cornelia Huck , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eric Blake , Markus Armbruster , Marcelo Tosatti , rick.p.edgecombe@intel.com, kvm@vger.kernel.org, qemu-devel@nongnu.org, xiaoyao.li@intel.com Subject: [PATCH v6 60/60] docs: Add TDX documentation Date: Tue, 5 Nov 2024 01:24:08 -0500 Message-Id: <20241105062408.3533704-61-xiaoyao.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20241105062408.3533704-1-xiaoyao.li@intel.com> References: <20241105062408.3533704-1-xiaoyao.li@intel.com> MIME-Version: 1.0 Received-SPF: pass client-ip=198.175.65.18; envelope-from=xiaoyao.li@intel.com; helo=mgamail.intel.com X-Spam_score_int: -39 X-Spam_score: -4.0 X-Spam_bar: ---- X-Spam_report: (-4.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.34, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, HK_RANDOM_ENVFROM=0.001, HK_RANDOM_FROM=0.781, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Add docs/system/i386/tdx.rst for TDX support, and add tdx in confidential-guest-support.rst Signed-off-by: Xiaoyao Li --- Changes in v6: - Add more information of "Feature configuration" - Mark TD Attestation as future work because KVM now drops the support of it. Changes in v5: - Add TD attestation section and update the QEMU parameter; Changes since v1: - Add prerequisite of private gmem; - update example command to launch TD; Changes since RFC v4: - add the restriction that kernel-irqchip must be split --- docs/system/confidential-guest-support.rst | 1 + docs/system/i386/tdx.rst | 155 +++++++++++++++++++++ docs/system/target-i386.rst | 1 + 3 files changed, 157 insertions(+) create mode 100644 docs/system/i386/tdx.rst diff --git a/docs/system/confidential-guest-support.rst b/docs/system/confidential-guest-support.rst index 0c490dbda2b7..66129fbab64c 100644 --- a/docs/system/confidential-guest-support.rst +++ b/docs/system/confidential-guest-support.rst @@ -38,6 +38,7 @@ Supported mechanisms Currently supported confidential guest mechanisms are: * AMD Secure Encrypted Virtualization (SEV) (see :doc:`i386/amd-memory-encryption`) +* Intel Trust Domain Extension (TDX) (see :doc:`i386/tdx`) * POWER Protected Execution Facility (PEF) (see :ref:`power-papr-protected-execution-facility-pef`) * s390x Protected Virtualization (PV) (see :doc:`s390x/protvirt`) diff --git a/docs/system/i386/tdx.rst b/docs/system/i386/tdx.rst new file mode 100644 index 000000000000..60106b29bf72 --- /dev/null +++ b/docs/system/i386/tdx.rst @@ -0,0 +1,155 @@ +Intel Trusted Domain eXtension (TDX) +==================================== + +Intel Trusted Domain eXtensions (TDX) refers to an Intel technology that extends +Virtual Machine Extensions (VMX) and Multi-Key Total Memory Encryption (MKTME) +with a new kind of virtual machine guest called a Trust Domain (TD). A TD runs +in a CPU mode that is designed to protect the confidentiality of its memory +contents and its CPU state from any other software, including the hosting +Virtual Machine Monitor (VMM), unless explicitly shared by the TD itself. + +Prerequisites +------------- + +To run TD, the physical machine needs to have TDX module loaded and initialized +while KVM hypervisor has TDX support and has TDX enabled. If those requirements +are met, the ``KVM_CAP_VM_TYPES`` will report the support of ``KVM_X86_TDX_VM``. + +Trust Domain Virtual Firmware (TDVF) +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Trust Domain Virtual Firmware (TDVF) is required to provide TD services to boot +TD Guest OS. TDVF needs to be copied to guest private memory and measured before +the TD boots. + +KVM vcpu ioctl ``KVM_TDX_INIT_MEM_REGION`` can be used to populates the TDVF +content into its private memory. + +Since TDX doesn't support readonly memslot, TDVF cannot be mapped as pflash +device and it actually works as RAM. "-bios" option is chosen to load TDVF. + +OVMF is the opensource firmware that implements the TDVF support. Thus the +command line to specify and load TDVF is ``-bios OVMF.fd`` + +Feature Configuration +--------------------- + +Unlike non-TDX VM, the CPU features (enumerated by CPU or MSR) of a TD is not +under full control of VMM. VMM can only configure part of features of a TD on +``KVM_TDX_INIT_VM`` command of VM scope ``MEMORY_ENCRYPT_OP`` ioctl. + +The configurable features have three types: + +- Attributes: + - PKS (bit 30) controls whether Supervisor Protection Keys is exposed to TD, + which determines related CPUID bit and CR4 bit; + - PERFMON (bit 63) controls whether PMU is exposed to TD. + +- XSAVE related features (XFAM): + XFAM is a 64b mask, which has the same format as XCR0 or IA32_XSS MSR. It + determines the set of extended features available for use by the guest TD. + +- CPUID features: + Only some bits of some CPUID leaves are directly configurable by VMM. + +What features can be configured is reported via TDX capabilities. + +TDX capabilities +~~~~~~~~~~~~~~~~ + +The VM scope ``MEMORY_ENCRYPT_OP`` ioctl provides command ``KVM_TDX_CAPABILITIES`` +to get the TDX capabilities from KVM. It returns a data structure of +``struct kvm_tdx_capabilities``, which tells the supported configuration of +attributes, XFAM and CPUIDs. + +TD attributes +~~~~~~~~~~~~~ + +QEMU supports configuring raw 64-bit TD attributes directly via "attributes" +property of "tdx-guest" object. Note, it's users' responsibility to provide a +valid value because some bits may not supported by current QEMU or KVM yet. + +QEMU also supports the configuration of individual attribute bits that are +supported by it, via propertyies of "tdx-guest" object. +E.g., "sept-ve-disable" (bit 63). + +MSR based features +~~~~~~~~~~~~~~~~ + +Current KVM doesn't support MSR based feature (e.g., MSR_IA32_ARCH_CAPABILITIES) +configuration for TDX, and it's a future work to enable it in QEMU when KVM adds +support of it. + +Feature check +~~~~~~~~~~~~~ + +QEMU checks if the final (CPU) features, determined by given cpu model and +explicit feature adjustment of "+featureA/-featureB", can be supported or not. +It can produce feature not supported warnning like + + "warning: host doesn't support requested feature: CPUID.07H:EBX.intel-pt [bit 25]" + +It will also procude warning like + + "warning: TDX forcibly sets the feature: CPUID.80000007H:EDX.invtsc [bit 8]" + +if the fixed-1 feature is requested to be disabled explicitly. This is newly +added to QEMU for TDX because TDX has fixed-1 features that are enfored enabled +by TDX module and VMM cannot disable them. + +Launching a TD (TDX VM) +----------------------- + +To launch a TDX guest, below are new added and required: + +.. parsed-literal:: + + |qemu_system_x86| \\ + -object tdx-guest,id=tdx0 \\ + -machine ...,kernel-irqchip=split,confidential-guest-support=tdx0 \\ + -bios OVMF.fd \\ + +restrictions +------------ + + - kernel-irqchip must be split; + + - No readonly support for private memory; + + - No SMM support: SMM support requires manipulating the guset register states + which is not allowed; + +Debugging +--------- + +Bit 0 of TD attributes, is DEBUG bit, which decides if the TD runs in off-TD +debug mode. When in off-TD debug mode, TD's VCPU state and private memory are +accessible via given SEAMCALLs. This requires KVM to expose APIs to invoke those +SEAMCALLs and resonponding QEMU change. + +It's targeted as future work. + +TD attestation +-------------- + +In TD guest, the attestation process is used to verify the TDX guest +trustworthiness to other entities before provisioning secrets to the guest. + +TD attestation is initiated first by calling TDG.MR.REPORT inside TD to get the +REPORT. Then the REPORT data needs to be converted into a remotely verifiable +Quote by SGX Quoting Enclave (QE). + +It's a future work in QEMU to add support of TD attestation since it lacks +support in current KVM. + +Live Migration +-------------- + +Future work. + +References +---------- + +- `TDX Homepage `__ + +- `SGX QE `__ diff --git a/docs/system/target-i386.rst b/docs/system/target-i386.rst index ab7af1a75d6e..43b09c79d6be 100644 --- a/docs/system/target-i386.rst +++ b/docs/system/target-i386.rst @@ -31,6 +31,7 @@ Architectural features i386/kvm-pv i386/sgx i386/amd-memory-encryption + i386/tdx OS requirements ~~~~~~~~~~~~~~~