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charset=us-ascii Content-Disposition: inline In-Reply-To: <20240701095505.165383-1-steven.price@arm.com> On Mon, Jul 01, 2024 at 10:54:50AM +0100, Steven Price wrote: > This series adds support for running Linux in a protected VM under the > Arm Confidential Compute Architecture (CCA). This has been updated > following the feedback from the v3 posting[1]. Thanks for the feedback! > Individual patches have a change log. But things to highlight: > > * a new patch ("firmware/psci: Add psci_early_test_conduit()") to > prevent SMC calls being made on systems which don't support them - > i.e. systems without EL2/EL3 - thanks Jean-Philippe! > > * two patches dropped (overriding set_fixmap_io). Instead > FIXMAP_PAGE_IO is modified to include PROT_NS_SHARED. When support > for assigning hardware devices to a realm guest is added this will > need to be brought back in some form. But for now it's just adding > complixity and confusion for no gain. > > * a new patch ("arm64: mm: Avoid TLBI when marking pages as valid") > which avoids doing an extra TLBI when doing the break-before-make. > Note that this changes the behaviour in other cases when making > memory valid. This should be safe (and saves a TLBI for those cases), > but it's a separate patch in case of regressions. > > * GIC ITT allocation now uses a custom genpool-based allocator. I > expect this will be replaced with a generic way of allocating > decrypted memory (see [4]), but for now this gets things working > without wasting too much memory. > > The ABI to the RMM from a realm (the RSI) is based on the final RMM v1.0 > (EAC 5) specification[2]. Future RMM specifications will be backwards > compatible so a guest using the v1.0 specification (i.e. this series) > will be able to run on future versions of the RMM without modification. > > This series is based on v6.10-rc1. It is also available as a git > repository: > > https://gitlab.arm.com/linux-arm/linux-cca cca-guest/v4 > > This series (the guest side) should be in a good state so please review > with the intention that this could be merged soon. The host side will > require more iteration so the versioning of the series will diverge - > so for now continue to use v3 for the host support. > > Introduction (unchanged from v2 posting) > ============ > A more general introduction to Arm CCA is available on the Arm > website[3], and links to the other components involved are available in > the overall cover letter. > > Arm Confidential Compute Architecture adds two new 'worlds' to the > architecture: Root and Realm. A new software component known as the RMM > (Realm Management Monitor) runs in Realm EL2 and is trusted by both the > Normal World and VMs running within Realms. This enables mutual > distrust between the Realm VMs and the Normal World. > > Virtual machines running within a Realm can decide on a (4k) > page-by-page granularity whether to share a page with the (Normal World) > host or to keep it private (protected). This protection is provided by > the hardware and attempts to access a page which isn't shared by the > Normal World will trigger a Granule Protection Fault. > > Realm VMs can communicate with the RMM via another SMC interface known > as RSI (Realm Services Interface). This series adds wrappers for the > full set of RSI commands and uses them to manage the Realm IPA State > (RIPAS) and to discover the configuration of the realm. > > The VM running within the Realm needs to ensure that memory that is > going to use is marked as 'RIPAS_RAM' (i.e. protected memory accessible > only to the guest). This could be provided by the VMM (and subject to > measurement to ensure it is setup correctly) or the VM can set it > itself. This series includes a patch which will iterate over all > described RAM and set the RIPAS. This is a relatively cheap operation, > and doesn't require memory donation from the host. Instead, memory can > be dynamically provided by the host on fault. An alternative would be to > update booting.rst and state this as a requirement, but this would > reduce the flexibility of the VMM to manage the available memory to the > guest (as the initial RIPAS state is part of the guest's measurement). > > Within the Realm the most-significant active bit of the IPA is used to > select whether the access is to protected memory or to memory shared > with the host. This series treats this bit as if it is attribute bit in > the page tables and will modify it when sharing/unsharing memory with > the host. > > This top bit usage also necessitates that the IPA width is made more > dynamic in the guest. The VMM will choose a width (and therefore which > bit controls the shared flag) and the guest must be able to identify > this bit to mask it out when necessary. PHYS_MASK_SHIFT/PHYS_MASK are > therefore made dynamic. > > To allow virtio to communicate with the host the shared buffers must be > placed in memory which has this top IPA bit set. This is achieved by > implementing the set_memory_{encrypted,decrypted} APIs for arm64 and > forcing the use of bounce buffers. For now all device access is > considered to required the memory to be shared, at this stage there is > no support for real devices to be assigned to a realm guest - obviously > if device assignment is added this will have to change. > > Finally the GIC is (largely) emulated by the (untrusted) host. The RMM > provides some management (including register save/restore) but the > ITS buffers must be placed into shared memory for the host to emulate. > There is likely to be future work to harden the GIC driver against a > malicious host (along with any other drivers used within a Realm guest). > > [1] https://lore.kernel.org/lkml/20240605093006.145492-1-steven.price%40arm.com > [2] https://developer.arm.com/documentation/den0137/1-0eac5/ > [3] https://www.arm.com/architecture/security-features/arm-confidential-compute-architecture > [4] https://lore.kernel.org/lkml/ZmNJdSxSz-sYpVgI%40arm.com > > Jean-Philippe Brucker (1): > firmware/psci: Add psci_early_test_conduit() > > Sami Mujawar (2): > arm64: rsi: Interfaces to query attestation token > virt: arm-cca-guest: TSM_REPORT support for realms > > Steven Price (7): > arm64: realm: Query IPA size from the RMM > arm64: Mark all I/O as non-secure shared > arm64: Make the PHYS_MASK_SHIFT dynamic > arm64: Enforce bounce buffers for realm DMA > arm64: mm: Avoid TLBI when marking pages as valid > irqchip/gic-v3-its: Share ITS tables with a non-trusted hypervisor > irqchip/gic-v3-its: Rely on genpool alignment > > Suzuki K Poulose (5): > arm64: rsi: Add RSI definitions > arm64: Detect if in a realm and set RIPAS RAM > arm64: Enable memory encrypt for Realms > arm64: Force device mappings to be non-secure shared > efi: arm64: Map Device with Prot Shared > > arch/arm64/Kconfig | 3 + > arch/arm64/include/asm/fixmap.h | 2 +- > arch/arm64/include/asm/io.h | 8 +- > arch/arm64/include/asm/mem_encrypt.h | 17 ++ > arch/arm64/include/asm/pgtable-hwdef.h | 6 - > arch/arm64/include/asm/pgtable-prot.h | 3 + > arch/arm64/include/asm/pgtable.h | 13 +- > arch/arm64/include/asm/rsi.h | 64 ++++++ > arch/arm64/include/asm/rsi_cmds.h | 134 +++++++++++ > arch/arm64/include/asm/rsi_smc.h | 142 ++++++++++++ > arch/arm64/include/asm/set_memory.h | 3 + > arch/arm64/kernel/Makefile | 3 +- > arch/arm64/kernel/efi.c | 2 +- > arch/arm64/kernel/rsi.c | 104 +++++++++ > arch/arm64/kernel/setup.c | 8 + > arch/arm64/mm/init.c | 10 +- > arch/arm64/mm/pageattr.c | 76 ++++++- > drivers/firmware/psci/psci.c | 25 +++ > drivers/irqchip/irq-gic-v3-its.c | 142 +++++++++--- > drivers/virt/coco/Kconfig | 2 + > drivers/virt/coco/Makefile | 1 + > drivers/virt/coco/arm-cca-guest/Kconfig | 11 + > drivers/virt/coco/arm-cca-guest/Makefile | 2 + > .../virt/coco/arm-cca-guest/arm-cca-guest.c | 211 ++++++++++++++++++ > include/linux/psci.h | 5 + > 25 files changed, 953 insertions(+), 44 deletions(-) > create mode 100644 arch/arm64/include/asm/mem_encrypt.h > create mode 100644 arch/arm64/include/asm/rsi.h > create mode 100644 arch/arm64/include/asm/rsi_cmds.h > create mode 100644 arch/arm64/include/asm/rsi_smc.h > create mode 100644 arch/arm64/kernel/rsi.c > create mode 100644 drivers/virt/coco/arm-cca-guest/Kconfig > create mode 100644 drivers/virt/coco/arm-cca-guest/Makefile > create mode 100644 drivers/virt/coco/arm-cca-guest/arm-cca-guest.c > > -- > 2.34.1 > > Hello, I tested this series on QEMU/KVM with the CCA patches(v2) and the FVP model. I could not find any evident issue. Tested-by: Matias Ezequiel Vara Larsen