Messages in this thread | | | Date | Fri, 14 Jul 2023 16:03:37 +0100 | Subject | Re: [RFC] Support for Arm CCA VMs on Linux | From | Suzuki K Poulose <> |
| |
Hi Jonathan
On 14/07/2023 14:46, Jonathan Cameron wrote: > On Fri, 27 Jan 2023 11:22:48 +0000 > Suzuki K Poulose <suzuki.poulose@arm.com> wrote: > > > Hi Suzuki, > > Looking at this has been on the backlog for a while from our side and we are finally > getting to it. So before we dive in and given it's been 6 months, I wanted to check > if you expect to post a new version shortly or if there is a rebased tree available?
Thanks for your interest. We have been updating our trees to the latest RMM specification (v1.0-eac2 now) and also rebasing Linux/KVM on top of v6.5-rc1. We will post this as soon as we have all the components ready (and the TF-RMM). At the earliest, this would be around early September.
That said, the revised version will have the following changes : - Changes to the Stage2 management - Changes to RMM memory management for Realm - PMU/SVE support
Otherwise, most of the changes remain the same (e.g., UABI). Happy to hear feedback on those areas.
Kind regards Suzuki
> > Jonathan > >> 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 >> >> 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@linux.intel.com >> >> Cc: Alexandru Elisei <alexandru.elisei@arm.com> >> Cc: Andrew Jones <andrew.jones@linux.dev> >> Cc: Catalin Marinas <catalin.marinas@arm.com> >> Cc: Chao Peng <chao.p.peng@linux.intel.com> >> Cc: Christoffer Dall <christoffer.dall@arm.com> >> Cc: Fuad Tabba <tabba@google.com> >> Cc: James Morse <james.morse@arm.com> >> Cc: Jean-Philippe Brucker <jean-philippe@linaro.org> >> Cc: Joey Gouly <Joey.Gouly@arm.com> >> Cc: Marc Zyngier <maz@kernel.org> >> Cc: Mark Rutland <mark.rutland@arm.com> >> Cc: Oliver Upton <oliver.upton@linux.dev> >> Cc: Paolo Bonzini <pbonzini@redhat.com> >> Cc: Quentin Perret <qperret@google.com> >> Cc: Sean Christopherson <seanjc@google.com> >> Cc: Steven Price <steven.price@arm.com> >> Cc: Thomas Huth <thuth@redhat.com> >> Cc: Will Deacon <will@kernel.org> >> Cc: Zenghui Yu <yuzenghui@huawei.com> >> To: linux-coco@lists.linux.dev >> To: kvmarm@lists.linux.dev >> Cc: kvmarm@lists.cs.columbia.edu >> Cc: linux-arm-kernel@lists.infradead.org >> To: linux-kernel@vger.kernel.org >> To: kvm@vger.kernel.org >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
| |