| Message ID | 20230127113932.166089-1-suzuki.poulose@arm.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | arm64: Support for Arm Confidential Compute Architecture | expand |
Hi Suzuki > This series is an initial version of the support for running VMs under the > Arm Confidential Compute Architecture. The purpose of the series is to gather > feedback on the proposed UABI changes for running Confidential VMs with KVM. > More information on the Arm CCA and instructions for how to get, build and run > the entire software stack is available here [0]. > > A new option, `--realm` is added to the the `run` command to mark the VM as a > confidential compute VM. This version doesn't use the Guest private memory [1] > support yet, instead uses normal anonymous/hugetlbfs backed memory. Our aim is > to switch to the guest private memory for the Realm. > > The host including the kernel and kvmtool, must not access any memory allocated > to the protected IPA of the Realm. > > The series adds the support for managing the lifecycle of the Realm, which includes: > * Configuration > * Creation of Realm (RD) > * Load initial memory images > * Creation of Realm Execution Contexts (RECs aka VCPUs)a > * Activation of the Realm. > > Patches are split as follows : > > Patches 1 and 2 are fixes to existing code. > Patch 3 adds a new option --nocompat to disable compat warnings > Patches 4 - 6 are some preparations for Realm specific changes. > > The remaining patches adds Realm support and using the --realm option is > enabled in patch 30. > > The v1.0 of the Realm Management Monitor (RMM) specification doesn't support > paging protected memory of a Realm. Thus all of the memory backing the RAM > is locked by the VMM. > > Since the IPA space of a Realm is split into Protected and Unprotected, with > one alias of the other, the VMM doubles the IPA Size for a Realm VM. > > The KVM support for Arm CCA is advertised with a new cap KVM_CAP_ARM_RME. > A new "VM type" field is defined in the vm_type for CREATE_VM ioctl to indicate > that a VM is "Realm". Once the VM is created, the life cycle of the Realm is > managed via KVM_ENABLE_CAP of KVM_CAP_ARM_RME. > > Command line options are also added to configure the Realm parameters. > These include : > - Hash algorithm for measurements > - Realm personalisation value > - SVE vector Length (Optional feature in v1.0 RMM spec. Not yet supported > by the TF-RMM. coming soon). > > Support for PMU and self-hosted debug (number of watchpoint/breakpoit registers) > are not supported yet in the KVM/RMM implementation. This will be added soon. > > The UABI doesn't support discovering the "supported" configuration values. In > real world, the Realm configuration 'affects' the initial measurement of the > Realms and which may be verified by a remote entity. Thus, the VMM is not at > liberty to make choices for configurations based on the "host" capabilities. > Instead, VMM should launch a Realm with the user requested parameters. If this > cannot be satisfied, there is no point in running the Realm. We are happy to > change this if there is interest. > > Special actions are required to load the initial memory images (e.g, kernel, > firmware, DTB, initrd) in to the Realm memory. > > For VCPUs, we add a new feature KVM_ARM_VCPU_REC, which will be used to control > the creation of the REC object (via KVM_ARM_VCPU_FINALIZE). This must be done > after the initial register state of the VCPUs are set. > RMM imposes an order in which the RECs are created. i.e., they must be created > in the ascending order of the MPIDR. This is for now a responsibility of the > VMM. > > Once the Realm images are loaded, VCPUs created, Realm is activated before > the first vCPU is run. > > virtio for the Realms enforces VIRTIO_F_ACCESS_PLATFORM flag. > > Also, added support for injecting SEA into the VM for unhandled MMIO. > I wonder if there is a plan to develop a dedicated (stand-alone) tool that allows a realm developer to calculate Realm Initial Measurements for realms. I mean a tool that can be compiled and run on a Linux PC machine. As you know, the remote attestation mechanism requires a verifier to be provisioned with reference values. In this case, a realm verifier should have access to the initial reference measurement (RIM) of a realm that is intended to be run on a remote Arm CCA platform. The algorithm that measures the initial state of realms (RIM) is highly sensitive to the content of a realm memory and the order of RMI operations. This means that not only the content of populated realm memory matters but also the implementation of the host components (e.g. kvm, kvmtool/qemu).In the of kvmtool-cca, the layout of memory and the content of DTB highly depend on the provided options (DTB is generated in run-time). Unfortunately, the content of DTB also depends on the linking order of object files (the order of DTB generation is imposed by __attribute__((constructor)) that is used to register devices). This complicates development of a separate tool for calculating RIM, as the tool would have to emulate all quirks of the kvmtool. One of the solution of retrieving Realm Initial Measurements seems to be running the whole firmware/software (e.g. kvmtool/Linux host/TF-RMM) stack on the FVP emulator and gathering the RIM directly from the TF-RMM. This would require a realm developer to have access to the whole firmware/software stack and the emulator of the CCA platform. The other solution would require the implementation of a dedicated tool. For instance, a sensible approach could be to extend the functionality of kvmtool. Is Arm going to develop a dedicated, stand-alone tool for calculating RIMs? What is the recommended way of retrieving/calculating RIMs for realms? Kind regards, Piotr Sawicki
This series is an initial version of the support for running VMs under the Arm Confidential Compute Architecture. The purpose of the series is to gather feedback on the proposed UABI changes for running Confidential VMs with KVM. More information on the Arm CCA and instructions for how to get, build and run the entire software stack is available here [0]. A new option, `--realm` is added to the the `run` command to mark the VM as a confidential compute VM. This version doesn't use the Guest private memory [1] support yet, instead uses normal anonymous/hugetlbfs backed memory. Our aim is to switch to the guest private memory for the Realm. The host including the kernel and kvmtool, must not access any memory allocated to the protected IPA of the Realm. The series adds the support for managing the lifecycle of the Realm, which includes: * Configuration * Creation of Realm (RD) * Load initial memory images * Creation of Realm Execution Contexts (RECs aka VCPUs)a * Activation of the Realm. Patches are split as follows : Patches 1 and 2 are fixes to existing code. Patch 3 adds a new option --nocompat to disable compat warnings Patches 4 - 6 are some preparations for Realm specific changes. The remaining patches adds Realm support and using the --realm option is enabled in patch 30. The v1.0 of the Realm Management Monitor (RMM) specification doesn't support paging protected memory of a Realm. Thus all of the memory backing the RAM is locked by the VMM. Since the IPA space of a Realm is split into Protected and Unprotected, with one alias of the other, the VMM doubles the IPA Size for a Realm VM. The KVM support for Arm CCA is advertised with a new cap KVM_CAP_ARM_RME. A new "VM type" field is defined in the vm_type for CREATE_VM ioctl to indicate that a VM is "Realm". Once the VM is created, the life cycle of the Realm is managed via KVM_ENABLE_CAP of KVM_CAP_ARM_RME. Command line options are also added to configure the Realm parameters. These include : - Hash algorithm for measurements - Realm personalisation value - SVE vector Length (Optional feature in v1.0 RMM spec. Not yet supported by the TF-RMM. coming soon). Support for PMU and self-hosted debug (number of watchpoint/breakpoit registers) are not supported yet in the KVM/RMM implementation. This will be added soon. The UABI doesn't support discovering the "supported" configuration values. In real world, the Realm configuration 'affects' the initial measurement of the Realms and which may be verified by a remote entity. Thus, the VMM is not at liberty to make choices for configurations based on the "host" capabilities. Instead, VMM should launch a Realm with the user requested parameters. If this cannot be satisfied, there is no point in running the Realm. We are happy to change this if there is interest. Special actions are required to load the initial memory images (e.g, kernel, firmware, DTB, initrd) in to the Realm memory. For VCPUs, we add a new feature KVM_ARM_VCPU_REC, which will be used to control the creation of the REC object (via KVM_ARM_VCPU_FINALIZE). This must be done after the initial register state of the VCPUs are set. RMM imposes an order in which the RECs are created. i.e., they must be created in the ascending order of the MPIDR. This is for now a responsibility of the VMM. Once the Realm images are loaded, VCPUs created, Realm is activated before the first vCPU is run. virtio for the Realms enforces VIRTIO_F_ACCESS_PLATFORM flag. Also, added support for injecting SEA into the VM for unhandled MMIO. A tree with the patches are also available here : https://gitlab.arm.com/linux-arm/kvmtool-cca cca/rfc-v1 Running the Realm ------------------ A realm VM can be launched using : $ lkvm run \ --realm \ --disable-sve \ [ --measurement-algo="sha256","sha512" ] \ [ --realm-pv="<realm-pv>" ] \ <normal-VM options> [0] https://lkml.kernel.org/r/20230127112248.136810-1-suzuki.poulose@arm.com [1] https://lkml.kernel.org/r/20221202061347.1070246-1-chao.p.peng@linux.intel.com To: kvmarm@lists.linux.dev To: kvm@vger.kernel.org Cc: Alexandru Elisei <alexandru.elisei@arm.com> Cc: Andrew Jones <andrew.jones@linux.dev> Cc: Christoffer Dall <christoffer.dall@arm.com> Cc: Fuad Tabba <tabba@google.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: Steven Price <steven.price@arm.com> Cc: Thomas Huth <thuth@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Zenghui Yu <yuzenghui@huawei.com> Cc: linux-coco@lists.linux.dev Cc: kvmarm@lists.cs.columbia.edu Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Alexandru Elisei (11): Add --nocompat option to disable compat warnings arm64: Add --realm command line option arm64: Lock realm RAM in memory arm64: Create Realm Descriptor arm: Add kernel size to VM context arm64: Populate initial realm contents arm64: Finalize realm VCPU after reset init: Add last_{init, exit} list macros arm64: Activate realm before the first VCPU is run arm64: Don't try to debug a realm arm64: Allow the user to create a realm Christoffer Dall (4): arm64: Create a realm virtual machine arm64: Add --measurement-algo command line option for a realm arm64: Don't try to set PSTATE for VCPUs belonging to a realm arm64: Specify SMC as the PSCI conduits for realms Joey Gouly (2): mmio: add arch hook for an unhandled MMIO access arm64: realm: inject an abort on an unhandled MMIO access Suzuki K Poulose (14): arm64: Disable MTE when CFI flash is emulated script: update_headers: Ignore missing architectures hw: cfi flash: Handle errors in memory transitions arm64: Check pvtime support against the KVM instance arm64: Check SVE capability on the VM instance arm64: Add option to disable SVE linux: Update kernel headers for RME support arm64: Add configuration step for Realms arm64: Add support for Realm Personalisation Value arm64: Add support for specifying the SVE vector length for Realm arm64: realm: Double the IPA space virtio: Add a wrapper for get_host_features virtio: Add arch specific hook for virtio host flags arm64: realm: Enforce virtio F_ACCESS_PLATFORM flag Makefile | 1 + arm/aarch32/include/asm/realm.h | 13 ++ arm/aarch32/kvm.c | 5 + arm/aarch64/include/asm/kvm.h | 64 ++++++ arm/aarch64/include/asm/realm.h | 13 ++ arm/aarch64/include/kvm/kvm-config-arch.h | 16 +- arm/aarch64/kvm-cpu.c | 41 +++- arm/aarch64/kvm.c | 95 ++++++++- arm/aarch64/pvtime.c | 4 +- arm/aarch64/realm.c | 229 ++++++++++++++++++++++ arm/fdt.c | 15 +- arm/include/arm-common/kvm-arch.h | 4 + arm/include/arm-common/kvm-config-arch.h | 5 + arm/kvm-cpu.c | 13 ++ arm/kvm.c | 75 ++++++- builtin-run.c | 5 +- guest_compat.c | 1 + hw/cfi_flash.c | 4 + include/kvm/kvm-config.h | 1 + include/kvm/kvm-cpu.h | 2 + include/kvm/kvm.h | 2 + include/kvm/util-init.h | 6 +- include/kvm/virtio.h | 2 + include/linux/kernel.h | 1 + include/linux/kvm.h | 22 ++- include/linux/virtio_blk.h | 19 -- include/linux/virtio_net.h | 14 +- include/linux/virtio_ring.h | 16 +- mips/kvm-cpu.c | 4 + mips/kvm.c | 5 + mmio.c | 3 + powerpc/kvm-cpu.c | 4 + powerpc/kvm.c | 5 + riscv/kvm-cpu.c | 4 + riscv/kvm.c | 5 + util/update_headers.sh | 1 + virtio/core.c | 8 + virtio/mmio-legacy.c | 2 +- virtio/mmio-modern.c | 2 +- virtio/pci-legacy.c | 2 +- virtio/pci-modern.c | 2 +- x86/kvm-cpu.c | 4 + x86/kvm.c | 5 + 43 files changed, 667 insertions(+), 77 deletions(-) create mode 100644 arm/aarch32/include/asm/realm.h create mode 100644 arm/aarch64/include/asm/realm.h create mode 100644 arm/aarch64/realm.c