Re: [PATCH v2 00/12] KVM: arm64: CCA: Prepare Realm memory management

[Steven Price <steven.price@arm.com>]

On 12/11/2026 09:08, Kohei Enju wrote:
> Hi Steve,

Hi Kohei,

> On 11/11 14:57, Steven Price wrote:
>> This series adds the memory management plumbing for CCA, building on the
>> basic RMM support [1]. Thank you to those who reviewed v1 - I'm
>> attempted to address all the comments.
>>
>> The patches introduce internal Realm VM state and RMI feature checks,
>> prepare Realm stage-2 setup and teardown, and provide RTT mapping and
>> invalidation helpers. Realm memslots are restricted to the lower half
>> of the IPA space because the protected and shared halves alias each
>> other. The final patch connects the helpers to KVM's stage-2 MMU
>> operations.
>>
>> This is the memory management portion of the larger Realm host series.
>> Realm descriptor creation, REC entry and exit, activation, and the new
>> uAPI follow in the integration stack. This series alone does not enable
>> Realm creation.
>>
>> As before there's an integration branch[2] that includes the realm
>> creation, REC entry/exit etc building on top of this series. I've also
>> pushed a git branch[3] of just this series.
>>
>> Changes since v1:
>> - Add a guest_memfd prerequisite patch that checks whether the backing
>>   file supports mmap when preparing an arm64 memslot.
>> - Combine the RMI availability and feature checks into one patch, and
>>   move Realm vCPU feature restrictions to the integration stack.
>> - Correct Realm IPA sizing and RTT teardown, including teardown before
>>   activation, RTT accounting, and handling of missing or folded RTTs.
>> - Rework RTT mapping to respect IPA and physical alignment, handle
>>   partial RMI progress, and retry interrupted operations.
>> - Preserve private mappings when a Realm guest_memfd memslot deletion is
>>   rejected, and tighten Realm fault handling and stage-2 destruction.
>>
>> [1] https://lore.kernel.org/all/20261007073537.2454351-1-suzuki.poulose@arm.com/
>> [2] https://gitlab.arm.com/linux-arm/linux-cca
>>     branch: cca-host-mm/v2/integration
>> [3] https://gitlab.arm.com/linux-arm/linux-cca
>>     branch: cca-host-mm/v2/mm
>>
>> Steven Price (7):
>>   KVM: arm64: CCA: Reserve the RMM mode
>>   KVM: arm64: guest_memfd: Check mmap support when preparing memslot
>>   KVM: arm64: CCA: Check RMI support and features at init
>>   KVM: arm64: CCA: Add basic infrastructure for creating a realm
>>   KVM: arm64: CCA: Tear down RTTs
>>   KVM: arm64: CCA: Add Realm RTT mapping and invalidation helpers
>>   KVM: arm64: CCA: Support runtime faulting of memory
>>
>> Suzuki K Poulose (5):
>>   KVM: arm64: CCA: Introduce Realms
>>   KVM: arm64: Handle attributes in stage2_unmap_range
>>   KVM: Allow architectures to reject memslot changes before invalidation
>>   KVM: arm64: CCA: Prevent memslot modifications after Realm creation
>>   KVM: arm64: CCA: Add Realm stage-2 MMU operations
> 
> I've tested the integration branch [2] including this series on our
> hardware using the QEMU-VMM proposed in:
>   https://lore.kernel.org/qemu-devel/20261002202026.1204110-1-mathieu.poirier@linaro.org/
> 
> The Realm guest VM (32 vCPUs, 16 GiB RAM) booted successfully. To
> exercise the guest with a more realistic workload, I also performed a
> full Linux kernel build, which completed successfully.

Awesome - thank you very much for testing.

> A Tested-by tag might not be carried over to the next revision, if any,
> but anyway, for this series:
> 
> Tested-by: Kohei Enju <enju.kohei@fujitsu.com>

Thanks,
Steve