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authorLinus Torvalds <torvalds@linux-foundation.org>2013-09-04 17:45:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-04 17:45:39 -0700
commitcf39c8e5352b4fb9efedfe7e9acb566a85ed847c (patch)
tree58d9f4b8c2ac48134264f1480cfc35b36462c4f4 /Documentation
parent3398d252a4da80c47fe9b802184fa0a792387732 (diff)
parent23b7eaf8220721892975610dd0ae5c846a34dcb4 (diff)
Merge tag 'stable/for-linus-3.12-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull Xen updates from Konrad Rzeszutek Wilk: "A couple of features and a ton of bug-fixes. There is also some maintership changes. Jeremy is enjoying the full-time work at the startup and as much as he would love to help - he can't find the time. I have a bunch of other things that I promised to work on - paravirt diet, get SWIOTLB working everywhere, etc, but haven't been able to find the time. As such both David Vrabel and Boris Ostrovsky have graciously volunteered to help with the maintership role. They will keep the lid on regressions, bug-fixes, etc. I will be in the background to help - but eventually there will be less of me doing the Xen GIT pulls and more of them. Stefano is still doing the ARM/ARM64 and will continue on doing so. Features: - Xen Trusted Platform Module (TPM) frontend driver - with the backend in MiniOS. - Scalability improvements in event channel. - Two extra Xen co-maintainers (David, Boris) and one going away (Jeremy) Bug-fixes: - Make the 1:1 mapping work during early bootup on selective regions. - Add scratch page to balloon driver to deal with unexpected code still holding on stale pages. - Allow NMIs on PV guests (64-bit only) - Remove unnecessary TLB flush in M2P code. - Fixes duplicate callbacks in Xen granttable code. - Fixes in PRIVCMD_MMAPBATCH ioctls to allow retries - Fix for events being lost due to rescheduling on different VCPUs. - More documentation" * tag 'stable/for-linus-3.12-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (23 commits) hvc_xen: Remove unnecessary __GFP_ZERO from kzalloc drivers/xen-tpmfront: Fix compile issue with missing option. xen/balloon: don't set P2M entry for auto translated guest xen/evtchn: double free on error Xen: Fix retry calls into PRIVCMD_MMAPBATCH*. xen/pvhvm: Initialize xen panic handler for PVHVM guests xen/m2p: use GNTTABOP_unmap_and_replace to reinstate the original mapping xen: fix ARM build after 6efa20e4 MAINTAINERS: Remove Jeremy from the Xen subsystem. xen/events: document behaviour when scanning the start word for events x86/xen: during early setup, only 1:1 map the ISA region x86/xen: disable premption when enabling local irqs swiotlb-xen: replace dma_length with sg_dma_len() macro swiotlb: replace dma_length with sg_dma_len() macro xen/balloon: set a mapping for ballooned out pages xen/evtchn: improve scalability by using per-user locks xen/p2m: avoid unneccesary TLB flush in m2p_remove_override() MAINTAINERS: Add in two extra co-maintainers of the Xen tree. MAINTAINERS: Update the Xen subsystem's with proper mailing list. xen: replace strict_strtoul() with kstrtoul() ...
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+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.

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