From nobody Sat Apr 5 13:51:48 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass header.i=@intel.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=intel.com ARC-Seal: i=1; a=rsa-sha256; t=1743515940; cv=none; d=zohomail.com; s=zohoarc; b=hfUd2RP2mmTqnA3qrHrrDSEDTLns95JNJ/t779hpMDyUOUIjNKHnzk6aUId6CnWCfFbhbmPFCn/DyI6ij7idiaj28HqLRGxyCiJQ35rbFfnPyPTAyU61EwnMrpvBu7vxe9KwfQJ2m9QRCK9PgidRjdOMsXgM44Xsi34hmUTrfL0= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1743515940; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=lwvWDxfp8dtWiHJbMTWjdOivjhU1yAFD1PfNNXiBVfA=; b=HLMVR4MtjmdJhfvL69na/dNb8XZl80XlExTgjKwXms19tl9yqWdB9wh8W9O75320SF8cdnVqM1WJ7Rm/oW7V2Gt2B/wPixpL1FsobxZeBVTxuEU1dgKGh+hjdW1XeWGn7PFZDft8xJDtHnmUU9jTtbPKGH5OOCSd9Nug4LIDwFY= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=@intel.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 174351594051585.27422432508433; Tue, 1 Apr 2025 06:59:00 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tzbyy-00069T-Pm; Tue, 01 Apr 2025 09:48:49 -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 1tzbvY-0002VS-Sa for qemu-devel@nongnu.org; Tue, 01 Apr 2025 09:45:17 -0400 Received: from mgamail.intel.com ([192.198.163.16]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tzbvU-0006Zf-6F for qemu-devel@nongnu.org; Tue, 01 Apr 2025 09:45:16 -0400 Received: from fmviesa008.fm.intel.com ([10.60.135.148]) by fmvoesa110.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Apr 2025 06:43:30 -0700 Received: from lxy-clx-4s.sh.intel.com ([10.239.48.52]) by fmviesa008.fm.intel.com with ESMTP; 01 Apr 2025 06:43:27 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1743515112; x=1775051112; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=EUwHVgF5vEEMvJW0RWlFhvQxAskobUwBHDJmxFXAZbY=; b=WuztuGS6aJqYd7EplKBdx6zJUf0XwH2XgrNmXcWzzk5jbtpIekayWQlU lre2rI9cyT1CcOYTFGYsn+ZHFc3jLTqUVV1x5UUM0cMmntWERm8WtnV3X qc1AIwdF92vTYScWRMU0cJiAyTwzzZyGw2bhkNkXEY2R4baYtpP+qMBD/ CSPTpmIadxc03TyD+YWf+tCIgR4fGP8O/jtuXtsz87jPnaxQLvPFWdhja kuIl8BKtt8JyzY4t2FvM/ymjqe1DE/1GVaRgj/ncAyh1TMj8CEZBGcPBs H2UdnmMuiEquyJrIiQDyZtuk/M0A4tCRE1OcJHadZy6sYUUY+1qb/q0uG w==; X-CSE-ConnectionGUID: i5tOTME1R/OYVhvKMLJjXA== X-CSE-MsgGUID: jeFsBnx7QrOAGFjdBKJpYQ== X-IronPort-AV: E=McAfee;i="6700,10204,11391"; a="32433617" X-IronPort-AV: E=Sophos;i="6.14,293,1736841600"; d="scan'208";a="32433617" X-CSE-ConnectionGUID: uIOZPd4uQfmZWINjGpHygA== X-CSE-MsgGUID: tYVyRyOhQjC9xJGrW5peuA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.14,293,1736841600"; d="scan'208";a="126640311" From: Xiaoyao Li To: Paolo Bonzini , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Cc: "Michael S. Tsirkin" , Markus Armbruster , Francesco Lavra , Marcelo Tosatti , qemu-devel@nongnu.org, =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Rick Edgecombe , Xiaoyao Li Subject: [PATCH v8 55/55] docs: Add TDX documentation Date: Tue, 1 Apr 2025 09:02:05 -0400 Message-Id: <20250401130205.2198253-56-xiaoyao.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250401130205.2198253-1-xiaoyao.li@intel.com> References: <20250401130205.2198253-1-xiaoyao.li@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=192.198.163.16; envelope-from=xiaoyao.li@intel.com; helo=mgamail.intel.com X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.997, 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=0.999, 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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @intel.com) X-ZM-MESSAGEID: 1743515941515019000 Content-Type: text/plain; charset="utf-8" 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 | 156 +++++++++++++++++++++ docs/system/target-i386.rst | 1 + 3 files changed, 158 insertions(+) create mode 100644 docs/system/i386/tdx.rst diff --git a/docs/system/confidential-guest-support.rst b/docs/system/confi= dential-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: =20 * AMD Secure Encrypted Virtualization (SEV) (see :doc:`i386/amd-memory-enc= ryption`) +* 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`) =20 diff --git a/docs/system/i386/tdx.rst b/docs/system/i386/tdx.rst new file mode 100644 index 000000000000..ea2e601dde9a --- /dev/null +++ b/docs/system/i386/tdx.rst @@ -0,0 +1,156 @@ +Intel Trusted Domain eXtension (TDX) +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +Intel Trusted Domain eXtensions (TDX) refers to an Intel technology that e= xtends +Virtual Machine Extensions (VMX) and Multi-Key Total Memory Encryption (MK= TME) +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 initia= lized +while KVM hypervisor has TDX support and has TDX enabled. If those require= ments +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 populate 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 are= 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 T= D. + +- 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_CAPABI= LITIES`` +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 "attribute= s" +property of "tdx-guest" object. Note, it's users' responsibility to provid= e 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 properties of "tdx-guest" object. +E.g., "sept-ve-disable" (bit 28). + +MSR based features +~~~~~~~~~~~~~~~~~~ + +Current KVM doesn't support MSR based feature (e.g., MSR_IA32_ARCH_CAPABIL= ITIES) +configuration for TDX, and it's a future work to enable it in QEMU when KV= M 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 warning like + + "warning: host doesn't support requested feature: CPUID.07H:EBX.intel-pt= [bit 25]" + +It can also produce 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 new= ly +added to QEMU for TDX because TDX has fixed-1 features that are forcibly e= nabled +by TDX module and VMM cannot disable them. + +Launching a TD (TDX VM) +----------------------- + +To launch a TD, the necessary command line options are tdx-guest object and +split kernel-irqchip, as below: + +.. parsed-literal:: + + |qemu_system_x86| \\ + -object tdx-guest,id=3Dtdx0 \\ + -machine ...,kernel-irqchip=3Dsplit,confidential-guest-support=3Dt= dx0 \\ + -bios OVMF.fd \\ + +Restrictions +------------ + + - kernel-irqchip must be split; + + - No readonly support for private memory; + + - No SMM support: SMM support requires manipulating the guest register st= ates + 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 corresonponding 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 ge= t the +REPORT. Then the REPORT data needs to be converted into a remotely verifia= ble +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 =20 OS requirements ~~~~~~~~~~~~~~~ --=20 2.34.1