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author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-12-12 21:58:13 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-12-12 21:58:13 -0800 |
commit | e7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba (patch) | |
tree | f63906f41699c8e38af9d12b063e2ceab0286ef2 /Documentation/security/tpm/xen-tpmfront.txt | |
parent | Merge branch 'akpm' (patches from Andrew) (diff) | |
parent | dma-buf: Extract dma-buf.rst (diff) | |
download | linux-dev-e7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba.tar.xz linux-dev-e7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba.zip |
Merge tag 'docs-4.10' of git://git.lwn.net/linux
Pull documentation update from Jonathan Corbet:
"These are the documentation changes for 4.10.
It's another busy cycle for the docs tree, as the sphinx conversion
continues. Highlights include:
- Further work on PDF output, which remains a bit of a pain but
should be more solid now.
- Five more DocBook template files converted to Sphinx. Only 27 to
go... Lots of plain-text files have also been converted and
integrated.
- Images in binary formats have been replaced with more
source-friendly versions.
- Various bits of organizational work, including the renaming of
various files discussed at the kernel summit.
- New documentation for the device_link mechanism.
... and, of course, lots of typo fixes and small updates"
* tag 'docs-4.10' of git://git.lwn.net/linux: (193 commits)
dma-buf: Extract dma-buf.rst
Update Documentation/00-INDEX
docs: 00-INDEX: document directories/files with no docs
docs: 00-INDEX: remove non-existing entries
docs: 00-INDEX: add missing entries for documentation files/dirs
docs: 00-INDEX: consolidate process/ and admin-guide/ description
scripts: add a script to check if Documentation/00-INDEX is sane
Docs: change sh -> awk in REPORTING-BUGS
Documentation/core-api/device_link: Add initial documentation
core-api: remove an unexpected unident
ppc/idle: Add documentation for powersave=off
Doc: Correct typo, "Introdution" => "Introduction"
Documentation/atomic_ops.txt: convert to ReST markup
Documentation/local_ops.txt: convert to ReST markup
Documentation/assoc_array.txt: convert to ReST markup
docs-rst: parse-headers.pl: cleanup the documentation
docs-rst: fix media cleandocs target
docs-rst: media/Makefile: reorganize the rules
docs-rst: media: build SVG from graphviz files
docs-rst: replace bayer.png by a SVG image
...
Diffstat (limited to 'Documentation/security/tpm/xen-tpmfront.txt')
-rw-r--r-- | Documentation/security/tpm/xen-tpmfront.txt | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/Documentation/security/tpm/xen-tpmfront.txt b/Documentation/security/tpm/xen-tpmfront.txt new file mode 100644 index 000000000000..69346de87ff3 --- /dev/null +++ b/Documentation/security/tpm/xen-tpmfront.txt @@ -0,0 +1,113 @@ +Virtual TPM interface for Xen + +Authors: Matthew Fioravante (JHUAPL), Daniel De Graaf (NSA) + +This document describes the virtual Trusted Platform Module (vTPM) subsystem for +Xen. The reader is assumed to have familiarity with building and installing Xen, +Linux, and a basic understanding of the TPM and vTPM concepts. + +INTRODUCTION + +The goal of this work is to provide a TPM functionality to a virtual guest +operating system (in Xen terms, a DomU). This allows programs to interact with +a TPM in a virtual system the same way they interact with a TPM on the physical +system. Each guest gets its own unique, emulated, software TPM. However, each +of the vTPM's secrets (Keys, NVRAM, etc) are managed by a vTPM Manager domain, +which seals the secrets to the Physical TPM. If the process of creating each of +these domains (manager, vTPM, and guest) is trusted, the vTPM subsystem extends +the chain of trust rooted in the hardware TPM to virtual machines in Xen. Each +major component of vTPM is implemented as a separate domain, providing secure +separation guaranteed by the hypervisor. The vTPM domains are implemented in +mini-os to reduce memory and processor overhead. + +This mini-os vTPM subsystem was built on top of the previous vTPM work done by +IBM and Intel corporation. + + +DESIGN OVERVIEW +--------------- + +The architecture of vTPM is described below: + ++------------------+ +| Linux DomU | ... +| | ^ | +| v | | +| xen-tpmfront | ++------------------+ + | ^ + v | ++------------------+ +| mini-os/tpmback | +| | ^ | +| v | | +| vtpm-stubdom | ... +| | ^ | +| v | | +| mini-os/tpmfront | ++------------------+ + | ^ + v | ++------------------+ +| mini-os/tpmback | +| | ^ | +| v | | +| vtpmmgr-stubdom | +| | ^ | +| v | | +| mini-os/tpm_tis | ++------------------+ + | ^ + v | ++------------------+ +| Hardware TPM | ++------------------+ + + * Linux DomU: The Linux based guest that wants to use a vTPM. There may be + more than one of these. + + * xen-tpmfront.ko: Linux kernel virtual TPM frontend driver. This driver + provides vTPM access to a Linux-based DomU. + + * mini-os/tpmback: Mini-os TPM backend driver. The Linux frontend driver + connects to this backend driver to facilitate communications + between the Linux DomU and its vTPM. This driver is also + used by vtpmmgr-stubdom to communicate with vtpm-stubdom. + + * vtpm-stubdom: A mini-os stub domain that implements a vTPM. There is a + one to one mapping between running vtpm-stubdom instances and + logical vtpms on the system. The vTPM Platform Configuration + Registers (PCRs) are normally all initialized to zero. + + * mini-os/tpmfront: Mini-os TPM frontend driver. The vTPM mini-os domain + vtpm-stubdom uses this driver to communicate with + vtpmmgr-stubdom. This driver is also used in mini-os + domains such as pv-grub that talk to the vTPM domain. + + * vtpmmgr-stubdom: A mini-os domain that implements the vTPM manager. There is + only one vTPM manager and it should be running during the + entire lifetime of the machine. This domain regulates + access to the physical TPM on the system and secures the + persistent state of each vTPM. + + * mini-os/tpm_tis: Mini-os TPM version 1.2 TPM Interface Specification (TIS) + driver. This driver used by vtpmmgr-stubdom to talk directly to + the hardware TPM. Communication is facilitated by mapping + hardware memory pages into vtpmmgr-stubdom. + + * Hardware TPM: The physical TPM that is soldered onto the motherboard. + + +INTEGRATION WITH XEN +-------------------- + +Support for the vTPM driver was added in Xen using the libxl toolstack in Xen +4.3. See the Xen documentation (docs/misc/vtpm.txt) for details on setting up +the vTPM and vTPM Manager stub domains. Once the stub domains are running, a +vTPM device is set up in the same manner as a disk or network device in the +domain's configuration file. + +In order to use features such as IMA that require a TPM to be loaded prior to +the initrd, the xen-tpmfront driver must be compiled in to the kernel. If not +using such features, the driver can be compiled as a module and will be loaded +as usual. |