We are happy to announce an early RFC version of the Arm Confidential
Compute Architecture (CCA) support for the Kvmtool guest firmware.
The intention is to seek early feedback in the following areas:
* Integration of the Arm CCA in ArmVirtPkg
* Generalise the operations wherever possible with other Confidential
Compute solutions and Virtual Machine Managers (VMMs)
* Guest firmware support for Realms.
Introduction
============
Arm Confidential Compute Architecture (CCA)
-------------------------------------------
Arm CCA is a reference software architecture and implementation that
builds on the Realm Management Extension (RME), enabling the execution
of Virtual machines (VMs), while preventing access by more privileged
software, such as hypervisor. Arm CCA allows the hypervisor to control
the VM, but removes the right for access to the code, register state or
data used by VM.
More information on the architecture is available here [0].
Realm World || Normal World || Secure World ||
|| | || ||
EL0 x---------x || x----x | x------x || ||
| Realm | || | | | | | || ||
| VM* | || | VM | | | | || ||
|x-------x| || | | | | | || ||
|| || || | | | | H | || ||
|| Guest || || | | | | | || ||
----|| OS ||--------||-| |---| o |-||----------------||
|| || || | | | | | || ||
|x-------x| || | | | | s | || ||
| ^ | || | | | | | || ||
| | | || | | | | t | || ||
|+-------+| || | | | | | || ||
|| REALM || || | | | | | || ||
|| GUEST || || | | | | O | || ||
|| UEFI || || | | | | | || ||
|+-------+| || | | | | S | || ||
EL1 x---------x || x----x | | | || ||
^ || | | | || ||
| || | | | || ||
-------- R*------------||----------| |-||----------------||
S || | | || ||
I || x-->| | || ||
| || | | | || ||
| || | x------x || ||
| || | ^ || ||
v || SMC | || ||
x-------x || | x------x || ||
| RMM* | || | | HOST | || ||
x-------x || | | UEFI | || ||
^ || | x------x || ||
EL2 | || | || ||
| || | || ||
=========|=====================|================================
| |
x------- *RMI* -------x
EL3 Root World
EL3 Firmware
===============================================================
Where:
RMM - Realm Management Monitor
RMI - Realm Management Interface
RSI - Realm Service Interface
SMC - Secure Monitor Call
RME introduces two added additional worlds, "Realm world" and "Root
World" in addition to the traditional Secure world and Normal world.
The Arm CCA defines a new component, Realm Management Monitor (RMM)
that runs at R-EL2. This is a standard piece of firmware, verified,
installed and loaded by the EL3 firmware (e.g., TF-A), at system boot.
The RMM provides a standard interface Realm Management Interface (RMI)
to the Normal world hypervisor to manage the VMs running in the Realm
world (also called Realms). These are exposed via SMC and are routed
through the EL3 firmware.
The RMM also provides certain services to the Realms via SMC, called
the Realm Service Interface (RSI). These include:
- Realm Guest Configuration
- Attestation & Measurement services
- Managing the state of an Intermediate Physical Address (IPA aka GPA)
page
- Host Call service (Communication with the Normal world Hypervisor).
The specification for the RMM software is currently at *v1.0-eac0* and
the latest version is available here [1].
The Trusted Firmware foundation has an implementation of the RMM -
TF-RMM - available here [3].
Implementation
==============
This version of the Realm Guest UEFI firmware is intended to be
used with the Linux Kernel RFC stack[6][11] and is based on the
RMM specification v1.0-BET0[2].
We plan to update the Guest UEFI Firmware to support the latest
version of the RMMv1.0 spec in the coming revisions.
This release includes the following:
a) Boot a Linux Kernel in a Realm VM using the Realm Guest UEFI
firmware
b) Hardware description is provided using ACPI tables.
c) Support for Virtio v1.0
d) All I/O are treated as non-secure/shared
e) Load the Linux Kernel and RootFS from a Virtio attached disk
using the Virtio-1.0 PCIe transport
f) Provide UEFI runtime variable support using Emulated Variable
support.
Overview of updates for enabling Arm CCA
----------------------------------------
The Arm CCA implementation is spread across a number of libraries
that provide required functionality during various phases of the
firmware boot.
The following libraries have been provided:
i. ArmCcaInitPeiLib - A library that implements the hook functions
in the PEI phase
ii. ArmCcaLib - A library that implements common functions like
checking if RME extension is implemented and to configure the
Protection attribute for the memory regions
iii. ArmCcaRsiLib - A library that implements the Realm Service
Interface functions.
A NULL implementation of the ArmCcaInitPeiLib and ArmCcaLib is also
provided for platforms that do not implement the RME extensions.
Additionally, the following DXE modules have been provided to implement
the required functionality in the DXE phase.
i. ArmCcaDxe - An APRIORI DXE that is responsible for configuring
the Monitor Conduit to SMC for a Realm
ii. RealmApertureManagementProtocolDxe - A DXE that implements the
Realm Aperture Management Protocol, used to manage the sharing
of buffers in a Realm with the Host
iii. ArmCcaIoMmuDxe - A driver which implements the EDKII_IOMMU_PROTOCOL
that provides the necessary hooks so that DMA operations can be
performed by bouncing buffers using pages shared with the Host.
Arm CCA updates in PEI phase
----------------------------
For supporting Arm CCA two hooks have been added in the PrePi module:
i. An early hook to configure the System Memory as Protected RAM
ii. A second hook after the MMU is initialised to perform the
remaining CCA initialisations like reading the Realm Config
to determine the IPA width of the realm, configuring the
Protection attribute for the MMIO regions, etc.
These hook functions are implemented in ArmCcaInitPeiLib. A NULL
version of the library has also been provided for implementations
that do not have the RME extensions.
Additionally, the ArmVirtMemInfoLib has been updated to implement
a platform specific hook function ArmCcaConfigureMmio() that can
configure the protection attribute for the MMIO regions for the
platform.
+=====+
|PrePi|
+=====+
|
_ModuleEntryPoint()
===================
|
DiscoverDramFromDt()
|
+--> ArmCcaInitPeiLib|ArmCcaConfigureSystemMemory()
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| // configure System Memory
---------------- // as Protected RAM.
|
...
|
--------
|
CEntryPoint()
|
PrePiMain()
===========
|
...
|
ProcessLibraryConstructorList()
|
MemoryPeim()
|
ArmCcaInitPeiLib|ArmCcaInitialize() // Perform Arm CCA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ // initialisations,
| // like reading the
| // Realm Config, etc.
|
ArmVirtMemInfoLib|ArmCcaConfigureMmio()
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| // Configure Protection attribute
-------- // for the MMIO region.
|
----------
|
...
|
+===+
|DXE|
+===+
Building the UEFI firmware
============================
a. Set up the development environment
Follow the steps as described in
https://developer.arm.com/documentation/102571/0100
Note: The EDK2 build system requires Python 3.7 or later.
b. The source code for the Host and Realm Guest firmware can
be downloaded from [12].
c. Building the Host UEFI firmware for FVP Base RevC AEM Model
Follow the instructions in
https://developer.arm.com/documentation/102571/0100
to "Build the firmware for Arm FVP Base AEMv8A-AEMv8A model
platform" based on your development environment configuration.
Note: The same firmware binary can be used for both the Arm FVP
Base AEMv8A-AEMv8A and the FVP Base RevC AEM Model.
d. Building the Realm Guest UEFI firmware for kvmtool:
To build the kvmtool guest firmware, run the following commands:
$build -a AARCH64 -t GCC5 -p ArmVirtPkg/ArmVirtKvmTool.dsc -b DEBUG
$build -a AARCH64 -t GCC5 -p ArmVirtPkg/ArmVirtKvmTool.dsc -b RELEASE
The Kvmtool guest firmware binaries are at the following location:
$WORKSPACE/Build/ArmVirtKvmTool-AARCH64/<DEBUG|RELEASE>_GCC5/
FV/KVMTOOL_EFI.fd
Running the stack
====================
To run/test the stack, you would need the following components:
i. FVP Base AEM RevC model with FEAT_RME support [4]
ii. TF-A firmware for EL3 [5]
iii. TF-A RMM for R-EL2 [3]
iv. Linux Kernel [6]
v. kvmtool [7]
vi. UEFI Firmware for Arm CCA [12].
Instructions for building the remaining firmware components and
running the model are available here [9]. Once, the host kernel
has finished booting, a Realm can be launched by invoking the
`lkvm` command as follows:
$ lkvm run --realm \
--measurement-algo=["sha256", "sha512"] \
--disable-sve \
--firmware KVMTOOL_EFI.fd \
-m 512 \
--irqchip=gicv3-its \
--force-pci \
--disk <Disk image containing the Guest Kernel & RootFS>
<normal-vm-options>
Where:
* --measurement-algo (Optional) specifies the algorithm selected for
creating the initial measurements by the RMM for this Realm (defaults
to sha256)
* GICv3 is mandatory for the Realms
* SVE is not yet supported in the TF-RMM, and thus must be disabled
using --disable-sve
* --force-pci is required as only Virtio-v1.0 PCIe transport is
supported.
An alternative is to use the Shrinkwrap tool [13] which provides a
complete solution to build and run the Arm CCA software stack.
Links
============
[0] Arm CCA Landing page (See Key Resources section for various documentations)
https://www.arm.com/armcca
[1] RMM Specification Latest
https://developer.arm.com/documentation/den0137/latest
[2] RMM v1.0-BET0 specification
https://developer.arm.com/documentation/den0137/1-0bet0/
[3] Trusted Firmware RMM - TF-RMM
https://www.trustedfirmware.org/projects/tf-rmm/
GIT: https://git.trustedfirmware.org/TF-RMM/tf-rmm.git
[4] FVP Base RevC AEM Model (available on x86_64 / Arm64 Linux)
https://developer.arm.com/Tools%20and%20Software/Fixed%20Virtual%20Platforms
[5] Trusted Firmware for A class
https://www.trustedfirmware.org/projects/tf-a/
[6] Linux kernel support for Arm-CCA
https://gitlab.arm.com/linux-arm/linux-cca
Host Support branch: cca-host/rfc-v1
Guest Support branch: cca-guest/rfc-v1
[7] kvmtool support for Arm CCA
https://gitlab.arm.com/linux-arm/kvmtool-cca cca/rfc-v1
[8] kvm-unit-tests support for Arm CCA
https://gitlab.arm.com/linux-arm/kvm-unit-tests-cca cca/rfc-v1
[9] Instructions for Building Firmware components and running the model, see
section 4.19.2 "Building and running TF-A with RME"
https://trustedfirmware-a.readthedocs.io/en/latest/components/realm-management-extension.html#building-and-running-tf-a-with-rme
[10] fd based Guest Private memory for KVM
https://lkml.kernel.org/r/20221202061347.1070246-1-chao.p.peng@linux.intel.com
[11] [RFC] Support for Arm CCA VMs on Linux
https://lore.kernel.org/linux-arm-kernel/20230127112248.136810-1-suzuki.poulose@arm.com/
[12] UEFI Firmware support for Arm CCA
Host Support:
- Repo: https://github.com/tianocore/edk2-platforms
- Branch: master
Guest Support:
- Repo: https://gitlab.arm.com/linux-arm/edk2-cca
- Branch: 2595_arm_cca_0abet0_rfc_v1
- URL: https://gitlab.arm.com/linux-arm/edk2-cca/-/tree/2595_arm_cca_0abet0_rfc_v1
[13] Building Arm CCA software stack using Shrinkwrap
https://shrinkwrap.docs.arm.com/en/latest/userguide/configstore/cca-3world.html
Sami Mujawar (30):
ArmVirtPkg: kvmtool: Add Emulated Runtime variable support
ArmPkg: Add helper function to detect RME
ArmPkg: Export SetMemoryRegionAttribute in ArmMmuLib
ArmPkg: Extend number of parameter registers in SMC call
ArmPkg & ArmVirtPkg: Make PcdMonitorConduitHvc a dynamic PCD
ArmVirtPkg: Add Arm CCA Realm Service Interface Library
ArmVirtPkg: ArmCcaRsiLib: Add interfaces to manage the Realm IPA state
ArmVirtPkg: ArmCcaRsiLib: Add an interface to get an attestation token
ArmVirtPkg: ArmCcaRsiLib: Add interfaces to get/extend REMs
ArmVirtPkg: ArmCcaRsiLib: Add an interface to make a RSI Host Call
ArmVirtPkg: Define a GUID HOB for IPA width of a Realm
ArmVirtPkg: Add library for Arm CCA initialisation in PEI
ArmVirtPkg: Add NULL instance of ArmCcaInitPeiLib
ArmVirtPkg: Add library for Arm CCA helper functions
ArmVirtPkg: Add Null instance of ArmCcaLib
ArmVirtPkg: Define an interface to configure MMIO regions for Arm CCA
ArmVirtPkg: CloudHv: Add a NULL implementation of ArmCcaConfigureMmio
ArmVirtPkg: Qemu: Add a NULL implementation of ArmCcaConfigureMmio
ArmVirtPkg: Xen: Add a NULL implementation of ArmCcaConfigureMmio
ArmVirtPkg: Configure the MMIO regions for Arm CCA
ArmVirtPkg: Kvmtool: Use Null version of DebugLib in PrePi
ArmVirtPkg: Add Arm CCA libraries for Kvmtool guest firmware
ArmVirtPkg: Arm CCA configure system memory in early Pei
ArmVirtPkg: Perform Arm CCA initialisation in the Pei phase
ArmVirtPkg: Add ArmCcaDxe for early DXE phase initialisation
ArmVirtPkg: Introduce Realm Aperture Management Protocol
ArmVirtPkg: IoMMU driver to DMA from Realms
ArmVirtPkg: Enable Virtio communication for Arm CCA
MdePkg: Warn if AArch64 RNDR instruction is not supported
ArmVirtPkg: Kvmtool: Switch to use BaseRng for AArch64
ArmPkg/ArmPkg.dec | 10 +-
ArmPkg/Include/Chipset/AArch64.h | 3 +-
ArmPkg/Include/Library/ArmLib.h | 15 +-
ArmPkg/Include/Library/ArmMmuLib.h | 22 +
ArmPkg/Include/Library/ArmSmcLib.h | 50 +-
ArmPkg/Library/ArmLib/AArch64/AArch64Lib.c | 16 +-
ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c | 16 +-
ArmPkg/Library/ArmMonitorLib/ArmMonitorLib.c | 4 +-
ArmPkg/Library/ArmSmcLib/AArch64/ArmSmc.S | 22 +-
ArmVirtPkg/ArmCcaDxe/ArmCcaDxe.c | 50 ++
ArmVirtPkg/ArmCcaDxe/ArmCcaDxe.inf | 39 +
ArmVirtPkg/ArmCcaIoMmuDxe/ArmCcaIoMmu.c | 813 ++++++++++++++++++++
ArmVirtPkg/ArmCcaIoMmuDxe/ArmCcaIoMmu.h | 66 ++
ArmVirtPkg/ArmCcaIoMmuDxe/ArmCcaIoMmuDxe.c | 59 ++
ArmVirtPkg/ArmCcaIoMmuDxe/ArmCcaIoMmuDxe.inf | 45 ++
ArmVirtPkg/ArmVirt.dsc.inc | 6 +-
ArmVirtPkg/ArmVirtKvmTool.dsc | 54 +-
ArmVirtPkg/ArmVirtKvmTool.fdf | 24 +-
ArmVirtPkg/ArmVirtPkg.dec | 7 +
ArmVirtPkg/Include/Library/ArmCcaInitPeiLib.h | 49 ++
ArmVirtPkg/Include/Library/ArmCcaLib.h | 114 +++
ArmVirtPkg/Include/Library/ArmCcaRsiLib.h | 253 ++++++
ArmVirtPkg/Include/Library/ArmVirtMemInfoLib.h | 19 +-
ArmVirtPkg/Include/Protocol/RealmApertureManagementProtocol.h | 103 +++
ArmVirtPkg/Library/ArmCcaInitPeiLib/ArmCcaInitPeiLib.c | 116 +++
ArmVirtPkg/Library/ArmCcaInitPeiLib/ArmCcaInitPeiLib.inf | 39 +
ArmVirtPkg/Library/ArmCcaInitPeiLibNull/ArmCcaInitPeiLibNull.c | 59 ++
ArmVirtPkg/Library/ArmCcaInitPeiLibNull/ArmCcaInitPeiLibNull.inf | 27 +
ArmVirtPkg/Library/ArmCcaLib/ArmCcaLib.c | 190 +++++
ArmVirtPkg/Library/ArmCcaLib/ArmCcaLib.inf | 34 +
ArmVirtPkg/Library/ArmCcaLibNull/ArmCcaLibNull.c | 117 +++
ArmVirtPkg/Library/ArmCcaLibNull/ArmCcaLibNull.inf | 28 +
ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsi.h | 48 ++
ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsiLib.c | 561 ++++++++++++++
ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsiLib.inf | 29 +
ArmVirtPkg/Library/CloudHvVirtMemInfoLib/CloudHvVirtMemInfoLib.c | 22 +-
ArmVirtPkg/Library/KvmtoolVirtMemInfoLib/KvmtoolVirtMemInfoLib.c | 39 +-
ArmVirtPkg/Library/KvmtoolVirtMemInfoLib/KvmtoolVirtMemInfoLib.inf | 3 +-
ArmVirtPkg/Library/QemuVirtMemInfoLib/QemuVirtMemInfoLib.c | 21 +
ArmVirtPkg/Library/XenVirtMemInfoLib/XenVirtMemInfoLib.c | 21 +
ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S | 6 +-
ArmVirtPkg/PrePi/ArmVirtPrePiUniCoreRelocatable.inf | 3 +-
ArmVirtPkg/PrePi/PrePi.c | 10 +-
ArmVirtPkg/RealmApertureManagementProtocolDxe/RealmApertureManagementProtocolDxe.c | 656 ++++++++++++++++
ArmVirtPkg/RealmApertureManagementProtocolDxe/RealmApertureManagementProtocolDxe.inf | 48 ++
MdePkg/Library/BaseRngLib/AArch64/Rndr.c | 8 +-
46 files changed, 3906 insertions(+), 38 deletions(-)
create mode 100644 ArmVirtPkg/ArmCcaDxe/ArmCcaDxe.c
create mode 100644 ArmVirtPkg/ArmCcaDxe/ArmCcaDxe.inf
create mode 100644 ArmVirtPkg/ArmCcaIoMmuDxe/ArmCcaIoMmu.c
create mode 100644 ArmVirtPkg/ArmCcaIoMmuDxe/ArmCcaIoMmu.h
create mode 100644 ArmVirtPkg/ArmCcaIoMmuDxe/ArmCcaIoMmuDxe.c
create mode 100644 ArmVirtPkg/ArmCcaIoMmuDxe/ArmCcaIoMmuDxe.inf
create mode 100644 ArmVirtPkg/Include/Library/ArmCcaInitPeiLib.h
create mode 100644 ArmVirtPkg/Include/Library/ArmCcaLib.h
create mode 100644 ArmVirtPkg/Include/Library/ArmCcaRsiLib.h
create mode 100644 ArmVirtPkg/Include/Protocol/RealmApertureManagementProtocol.h
create mode 100644 ArmVirtPkg/Library/ArmCcaInitPeiLib/ArmCcaInitPeiLib.c
create mode 100644 ArmVirtPkg/Library/ArmCcaInitPeiLib/ArmCcaInitPeiLib.inf
create mode 100644 ArmVirtPkg/Library/ArmCcaInitPeiLibNull/ArmCcaInitPeiLibNull.c
create mode 100644 ArmVirtPkg/Library/ArmCcaInitPeiLibNull/ArmCcaInitPeiLibNull.inf
create mode 100644 ArmVirtPkg/Library/ArmCcaLib/ArmCcaLib.c
create mode 100644 ArmVirtPkg/Library/ArmCcaLib/ArmCcaLib.inf
create mode 100644 ArmVirtPkg/Library/ArmCcaLibNull/ArmCcaLibNull.c
create mode 100644 ArmVirtPkg/Library/ArmCcaLibNull/ArmCcaLibNull.inf
create mode 100644 ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsi.h
create mode 100644 ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsiLib.c
create mode 100644 ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsiLib.inf
create mode 100644 ArmVirtPkg/RealmApertureManagementProtocolDxe/RealmApertureManagementProtocolDxe.c
create mode 100644 ArmVirtPkg/RealmApertureManagementProtocolDxe/RealmApertureManagementProtocolDxe.inf
--
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