* Suzuki K Poulose (suzuki.poulose@xxxxxxx) wrote: > Hi Dave > > Thanks for your response, and apologies for the delay. Response, in line. > > On 14/02/2023 17:13, Dr. David Alan Gilbert wrote: > > * Suzuki K Poulose (suzuki.poulose@xxxxxxx) wrote: > > > We are happy to announce the early RFC version of the Arm > > > Confidential Compute Architecture (CCA) support for the Linux > > > stack. The intention is to seek early feedback in the following areas: > > > * KVM integration of the Arm CCA > > > * KVM UABI for managing the Realms, seeking to generalise the operations > > > wherever possible with other Confidential Compute solutions. > > > Note: This version doesn't support Guest Private memory, which will be added > > > later (see below). > > > * Linux Guest support for Realms > > > > > > Arm CCA Introduction > > > ===================== > > > > > > The Arm CCA is a reference software architecture and implementation that builds > > > on the Realm Management Extension (RME), enabling the execution of Virtual > > > machines, while preventing access by more privileged software, such as hypervisor. > > > The Arm CCA allows the hypervisor to control the VM, but removes the right for > > > access to the code, register state or data that is used by VM. > > > More information on the architecture is available here[0]. > > > > > > Arm CCA Reference Software Architecture > > > > > > Realm World || Normal World || Secure World || > > > || | || || > > > EL0 x-------x || x----x | x------x || || > > > | Realm | || | | | | | || || > > > | | || | VM | | | | || || > > > ----| VM* |---------||-| |---| |-||----------------|| > > > | | || | | | | H | || || > > > EL1 x-------x || x----x | | | || || > > > ^ || | | o | || || > > > | || | | | || || > > > ------- R*------------------------| s -|--------------------- > > > S || | | || || > > > I || | t | || || > > > | || | | || || > > > v || x------x || || > > > EL2 RMM* || ^ || || > > > ^ || | || || > > > ========|=============================|======================== > > > | | SMC > > > 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 > > > > Hi, > > It's nice to see this full stack posted - thanks! > > > > Are there any pointers to information on attestation and similar > > measurement things? In particular, are there any plans for a vTPM > > The RMM v1.0 provides attestation and measurement services to the Realm, > via Realm Service Interface (RSI) calls. Can you point me at some docs for that? > However, there is no support > for partitioning the Realm VM with v1.0. This is currently under > development and should be available in the near future. > > With that in place, a vTPM could reside in a partition of the Realm VM along > side the OS in another. Does that answer your question ? Possibly; it would be great to be able to use a standard vTPM interface here rather than have to do anything special. People already have this working on AMD SEV-SNP. Dave > Kind regards > Suzuki > > > > for Realms - if there were, it would make life easy for us, since we > > can share some user space stuff with other CoCo systems. > > > > Dave > > > > > RME introduces a new security state "Realm world", in addition to the > > > traditional Secure and Non-Secure states. 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 standard interfaces - Realm Management Interface (RMI) - to the > > > Normal world hypervisor to manage the VMs running in the Realm world (also called > > > Realms in short). These are exposed via SMC and are routed through the EL3 > > > firmwre. > > > The RMI interface includes: > > > - Move a physical page from the Normal world to the Realm world > > > - Creating a Realm with requested parameters, tracked via Realm Descriptor (RD) > > > - Creating VCPUs aka Realm Execution Context (REC), with initial register state. > > > - Create stage2 translation table at any level. > > > - Load initial images into Realm Memory from normal world memory > > > - Schedule RECs (vCPUs) and handle exits > > > - Inject virtual interrupts into the Realm > > > - Service stage2 runtime faults with pages (provided by host, scrubbed by RMM). > > > - Create "shared" mappings that can be accessed by VMM/Hyp. > > > - Reclaim the memory allocated for the RAM and RTTs (Realm Translation Tables) > > > > > > However v1.0 of RMM specifications doesn't support: > > > - Paging protected memory of a Realm VM. Thus the pages backing the protected > > > memory region must be pinned. > > > - Live migration of Realms. > > > - Trusted Device assignment. > > > - Physical interrupt backed Virtual interrupts for Realms > > > > > > RMM also provides certain services to the Realms via SMC, called 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 specifications for the RMM software is currently at *v1.0-Beta2* 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 stack is based on the RMM specification v1.0-Beta0[2], with > > > following exceptions : > > > - TF-RMM/KVM currently doesn't support the optional features of PMU, > > > SVE and Self-hosted debug (coming soon). > > > - The RSI_HOST_CALL structure alignment requirement is reduced to match > > > RMM v1.0 Beta1 > > > - RMI/RSI version numbers do not match the RMM spec. This will be > > > resolved once the spec/implementation is complete, across TF-RMM+Linux stack. > > > > > > We plan to update the stack to support the latest version of the RMMv1.0 spec > > > in the coming revisions. > > > > > > This release includes the following components : > > > > > > a) Linux Kernel > > > i) Host / KVM support - Support for driving the Realms via RMI. This is > > > dependent on running in the Kernel at EL2 (aka VHE mode). Also provides > > > UABI for VMMs to manage the Realm VMs. The support is restricted to 4K page > > > size, matching the Stage2 granule supported by RMM. The VMM is responsible > > > for making sure the guest memory is locked. > > > > > > TODO: Guest Private memory[10] integration - We have been following the > > > series and support will be added once it is merged upstream. > > > ii) Guest support - Support for a Linux Kernel to run in the Realm VM at > > > Realm-EL1, using RSI services. This includes virtio support (virtio-v1.0 > > > only). All I/O are treated as non-secure/shared. > > > c) kvmtool - VMM changes required to manage Realm VMs. No guest private memory > > > as mentioned above. > > > d) kvm-unit-tests - Support for running in Realms along with additional tests > > > for RSI ABI. > > > > > > Running the stack > > > ==================== > > > > > > To run/test the stack, you would need the following components : > > > > > > 1) FVP Base AEM RevC model with FEAT_RME support [4] > > > 2) TF-A firmware for EL3 [5] > > > 3) TF-A RMM for R-EL2 [3] > > > 4) Linux Kernel [6] > > > 5) kvmtool [7] > > > 6) kvm-unit-tests [8] > > > > > > Instructions for building the firmware components and running the model are > > > available here [9]. Once, the host kernel is booted, a Realm can be launched by > > > invoking the `lkvm` commad as follows: > > > > > > $ lkvm run --realm \ > > > --measurement-algo=["sha256", "sha512"] \ > > > --disable-sve \ > > > <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 > > > > > > You may also run the kvm-unit-tests inside the Realm world, using the similar > > > options as above. > > > > > > > > > Links > > > ============ > > > > > > [0] Arm CCA Landing page (See Key Resources section for various documentations) > > > https://www.arm.com/architecture/security-features/arm-confidential-compute-architecture > > > > > > [1] RMM Specification Latest > > > https://developer.arm.com/documentation/den0137/latest > > > > > > [2] RMM v1.0-Beta0 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@xxxxxxxxxxxxxxx > > > > > > Cc: Alexandru Elisei <alexandru.elisei@xxxxxxx> > > > Cc: Andrew Jones <andrew.jones@xxxxxxxxx> > > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > > > Cc: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx> > > > Cc: Christoffer Dall <christoffer.dall@xxxxxxx> > > > Cc: Fuad Tabba <tabba@xxxxxxxxxx> > > > Cc: James Morse <james.morse@xxxxxxx> > > > Cc: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx> > > > Cc: Joey Gouly <Joey.Gouly@xxxxxxx> > > > Cc: Marc Zyngier <maz@xxxxxxxxxx> > > > Cc: Mark Rutland <mark.rutland@xxxxxxx> > > > Cc: Oliver Upton <oliver.upton@xxxxxxxxx> > > > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> > > > Cc: Quentin Perret <qperret@xxxxxxxxxx> > > > Cc: Sean Christopherson <seanjc@xxxxxxxxxx> > > > Cc: Steven Price <steven.price@xxxxxxx> > > > Cc: Thomas Huth <thuth@xxxxxxxxxx> > > > Cc: Will Deacon <will@xxxxxxxxxx> > > > Cc: Zenghui Yu <yuzenghui@xxxxxxxxxx> > > > To: linux-coco@xxxxxxxxxxxxxxx > > > To: kvmarm@xxxxxxxxxxxxxxx > > > Cc: kvmarm@xxxxxxxxxxxxxxxxxxxxx > > > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > > > To: linux-kernel@xxxxxxxxxxxxxxx > > > To: kvm@xxxxxxxxxxxxxxx > > > > -- Dr. David Alan Gilbert / dgilbert@xxxxxxxxxx / Manchester, UK
