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2025-01-08arm64: rsi: Add automatic arm-cca-guest module loadingJeremy Linton
The TSM module provides guest identification and attestation when a guest runs in CCA realm mode. By creating a dummy platform device, let's ensure the module is automatically loaded. The udev daemon loads the TSM module after it receives a device addition event. Once that happens, it can be used earlier in the boot process to decrypt the rootfs. Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Steven Price <steven.price@arm.com> Link: https://lore.kernel.org/r/20241220181236.172060-2-jeremy.linton@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2024-10-23arm64: Enable memory encrypt for RealmsSuzuki K Poulose
Use the memory encryption APIs to trigger a RSI call to request a transition between protected memory and shared memory (or vice versa) and updating the kernel's linear map of modified pages to flip the top bit of the IPA. This requires that block mappings are not used in the direct map for realm guests. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Co-developed-by: Steven Price <steven.price@arm.com> Signed-off-by: Steven Price <steven.price@arm.com> Link: https://lore.kernel.org/r/20241017131434.40935-10-steven.price@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2024-10-23arm64: Enforce bounce buffers for realm DMASteven Price
Within a realm guest it's not possible for a device emulated by the VMM to access arbitrary guest memory. So force the use of bounce buffers to ensure that the memory the emulated devices are accessing is in memory which is explicitly shared with the host. This adds a call to swiotlb_update_mem_attributes() which calls set_memory_decrypted() to ensure the bounce buffer memory is shared with the host. For non-realm guests or hosts this is a no-op. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Co-developed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Steven Price <steven.price@arm.com> Link: https://lore.kernel.org/r/20241017131434.40935-8-steven.price@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2024-10-23arm64: rsi: Map unprotected MMIO as decryptedSuzuki K Poulose
Instead of marking every MMIO as shared, check if the given region is "Protected" and apply the permissions accordingly. Reviewed-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Steven Price <steven.price@arm.com> Link: https://lore.kernel.org/r/20241017131434.40935-6-steven.price@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2024-10-23arm64: rsi: Add support for checking whether an MMIO is protectedSuzuki K Poulose
On Arm CCA, with RMM-v1.0, all MMIO regions are shared. However, in the future, an Arm CCA-v1.0 compliant guest may be run in a lesser privileged partition in the Realm World (with Arm CCA-v1.1 Planes feature). In this case, some of the MMIO regions may be emulated by a higher privileged component in the Realm world, i.e, protected. Thus the guest must decide today, whether a given MMIO region is shared vs Protected and create the stage1 mapping accordingly. On Arm CCA, this detection is based on the "IPA State" (RIPAS == RIPAS_IO). Provide a helper to run this check on a given range of MMIO. Also, provide a arm64 helper which may be hooked in by other solutions. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Steven Price <steven.price@arm.com> Link: https://lore.kernel.org/r/20241017131434.40935-5-steven.price@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2024-10-23arm64: realm: Query IPA size from the RMMSteven Price
The top bit of the configured IPA size is used as an attribute to control whether the address is protected or shared. Query the configuration from the RMM to assertain which bit this is. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Co-developed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Steven Price <steven.price@arm.com> Link: https://lore.kernel.org/r/20241017131434.40935-4-steven.price@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2024-10-23arm64: Detect if in a realm and set RIPAS RAMSuzuki K Poulose
Detect that the VM is a realm guest by the presence of the RSI interface. This is done after PSCI has been initialised so that we can check the SMCCC conduit before making any RSI calls. If in a realm then iterate over all memory ensuring that it is marked as RIPAS RAM. The loader is required to do this for us, however if some memory is missed this will cause the guest to receive a hard to debug external abort at some random point in the future. So for a belt-and-braces approach set all memory to RIPAS RAM. Any failure here implies that the RAM regions passed to Linux are incorrect so panic() promptly to make the situation clear. Reviewed-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Co-developed-by: Steven Price <steven.price@arm.com> Signed-off-by: Steven Price <steven.price@arm.com> Link: https://lore.kernel.org/r/20241017131434.40935-3-steven.price@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>