From: Steven Price <steven.price@arm•com>
To: Wei-Lin Chang <weilin.chang@arm•com>,
kvm@vger•kernel.org, kvmarm@lists•linux.dev
Cc: Catalin Marinas <catalin.marinas@arm•com>,
Marc Zyngier <maz@kernel•org>, Will Deacon <will@kernel•org>,
James Morse <james.morse@arm•com>,
Oliver Upton <oliver.upton@linux•dev>,
Suzuki K Poulose <suzuki.poulose@arm•com>,
Zenghui Yu <yuzenghui@huawei•com>,
linux-arm-kernel@lists•infradead.org,
linux-kernel@vger•kernel.org, Joey Gouly <joey.gouly@arm•com>,
Alexandru Elisei <alexandru.elisei@arm•com>,
Christoffer Dall <christoffer.dall@arm•com>,
Fuad Tabba <tabba@google•com>,
linux-coco@lists•linux.dev,
Ganapatrao Kulkarni <gankulkarni@os•amperecomputing.com>,
Gavin Shan <gshan@redhat•com>,
Shanker Donthineni <sdonthineni@nvidia•com>,
Alper Gun <alpergun@google•com>,
"Aneesh Kumar K . V" <aneesh.kumar@kernel•org>,
Emi Kisanuki <fj0570is@fujitsu•com>,
Vishal Annapurve <vannapurve@google•com>,
Lorenzo.Pieralisi2@arm•com
Subject: Re: [PATCH v14 13/44] arm64: RMI: Define the user ABI
Date: Thu, 4 Jun 2026 16:27:57 +0100 [thread overview]
Message-ID: <32d691c2-edfd-408c-bb49-7eba623bec11@arm.com> (raw)
In-Reply-To: <vixej2afqamvr7eaksoepr3wmpwzp73rtgrageeyuawa6azotw@payxzyhymwbt>
On 26/05/2026 23:17, Wei-Lin Chang wrote:
> On Wed, May 13, 2026 at 02:17:21PM +0100, Steven Price wrote:
>> There is one CAP which identified the presence of CCA, and one ioctl.
>> The ioctl is used to populate memory during creation of the realm as
>> this requires the RMM to copy data from an unprotected address to the
>> protected memory - CCA does not support memory conversion where the
>> memory contents is preserved as this is incompatible with memory
>> encryption.
>
> Nit:
> I believe spelling out the CAP and ioctl names can improve the commit
> message. Also "memory conversion" is a little vague, maybe
>
> ... CCA does not support shared <-> private memory conversion where ...
>
> would make this clearer?
Thanks for the suggestions - yes I agree that would make it clearer.
Thanks,
Steve
> Thanks,
> Wei-Lin Chang
>
>>
>> Signed-off-by: Steven Price <steven.price@arm•com>
>> ---
>> Changes since v13:
>> * KVM_ARM_VCPU_RMI_PSCI_COMPLETE removed.
>> * KVM_ARM_RMI_POPULATE documentation updated to reflect that the
>> structure is written by the kernel.
>> * CAP number bumped.
>> Changes since v12:
>> * Change KVM_ARM_RMI_POPULATE to update the structure with the amount
>> that has been progressed rather than return the number of bytes
>> populated.
>> * Describe the flag KVM_ARM_RMI_POPULATE_FLAGS_MEASURE.
>> * CAP number is bumped.
>> * NOTE: The PSCI ioctl may be removed in a future spec release.
>> Changes since v11:
>> * Completely reworked to be more implicit. Rather than having explicit
>> CAP operations to progress the realm construction these operations
>> are done when needed (on populating and on first vCPU run).
>> * Populate and PSCI complete are promoted to proper ioctls.
>> Changes since v10:
>> * Rename symbols from RME to RMI.
>> Changes since v9:
>> * Improvements to documentation.
>> * Bump the magic number for KVM_CAP_ARM_RME to avoid conflicts.
>> Changes since v8:
>> * Minor improvements to documentation following review.
>> * Bump the magic numbers to avoid conflicts.
>> Changes since v7:
>> * Add documentation of new ioctls
>> * Bump the magic numbers to avoid conflicts
>> Changes since v6:
>> * Rename some of the symbols to make their usage clearer and avoid
>> repetition.
>> Changes from v5:
>> * Actually expose the new VCPU capability (KVM_ARM_VCPU_REC) by bumping
>> KVM_VCPU_MAX_FEATURES - note this also exposes KVM_ARM_VCPU_HAS_EL2!
>> ---
>> Documentation/virt/kvm/api.rst | 40 ++++++++++++++++++++++++++++++++++
>> include/uapi/linux/kvm.h | 13 +++++++++++
>> 2 files changed, 53 insertions(+)
>>
>> diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
>> index 52bbbb553ce1..ca68aae7faa2 100644
>> --- a/Documentation/virt/kvm/api.rst
>> +++ b/Documentation/virt/kvm/api.rst
>> @@ -6553,6 +6553,37 @@ KVM_S390_KEYOP_SSKE
>> Sets the storage key for the guest address ``guest_addr`` to the key
>> specified in ``key``, returning the previous value in ``key``.
>>
>> +4.145 KVM_ARM_RMI_POPULATE
>> +--------------------------
>> +
>> +:Capability: KVM_CAP_ARM_RMI
>> +:Architectures: arm64
>> +:Type: vm ioctl
>> +:Parameters: struct kvm_arm_rmi_populate (in/out)
>> +:Returns: 0 on success, < 0 on error
>> +
>> +::
>> +
>> + struct kvm_arm_rmi_populate {
>> + __u64 base;
>> + __u64 size;
>> + __u64 source_uaddr;
>> + __u32 flags;
>> + __u32 reserved;
>> + };
>> +
>> +Populate a region of protected address space by copying the data from the
>> +(non-protected) user space pointer provided into a protected region (backed by
>> +guestmem_fd). It implicitly sets the destination region to RIPAS RAM. This is
>> +only valid before any VCPUs have been run. The ioctl might not populate the
>> +entire region and in this case the kernel updates the fields `base`, `size` and
>> +`source_uaddr`. User space may have to repeatedly call it until `size` is 0 to
>> +populate the entire region.
>> +
>> +`flags` can be set to `KVM_ARM_RMI_POPULATE_FLAGS_MEASURE` to request that the
>> +populated data is hashed and added to the guest's Realm Initial Measurement
>> +(RIM).
>> +
>> .. _kvm_run:
>>
>> 5. The kvm_run structure
>> @@ -8904,6 +8935,15 @@ helpful if user space wants to emulate instructions which are not
>> This capability can be enabled dynamically even if VCPUs were already
>> created and are running.
>>
>> +7.47 KVM_CAP_ARM_RMI
>> +--------------------
>> +
>> +:Architectures: arm64
>> +:Target: VM
>> +:Parameters: None
>> +
>> +This capability indicates that support for CCA realms is available.
>> +
>> 8. Other capabilities.
>> ======================
>>
>> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
>> index 6c8afa2047bf..b8cff0938041 100644
>> --- a/include/uapi/linux/kvm.h
>> +++ b/include/uapi/linux/kvm.h
>> @@ -996,6 +996,7 @@ struct kvm_enable_cap {
>> #define KVM_CAP_S390_USER_OPEREXEC 246
>> #define KVM_CAP_S390_KEYOP 247
>> #define KVM_CAP_S390_VSIE_ESAMODE 248
>> +#define KVM_CAP_ARM_RMI 249
>>
>> struct kvm_irq_routing_irqchip {
>> __u32 irqchip;
>> @@ -1669,4 +1670,16 @@ struct kvm_pre_fault_memory {
>> __u64 padding[5];
>> };
>>
>> +/* Available with KVM_CAP_ARM_RMI, only for VMs with KVM_VM_TYPE_ARM_REALM */
>> +#define KVM_ARM_RMI_POPULATE _IOWR(KVMIO, 0xd7, struct kvm_arm_rmi_populate)
>> +#define KVM_ARM_RMI_POPULATE_FLAGS_MEASURE (1 << 0)
>> +
>> +struct kvm_arm_rmi_populate {
>> + __u64 base;
>> + __u64 size;
>> + __u64 source_uaddr;
>> + __u32 flags;
>> + __u32 reserved;
>> +};
>> +
>> #endif /* __LINUX_KVM_H */
>> --
>> 2.43.0
>>
next prev parent reply other threads:[~2026-06-04 15:28 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-13 13:17 [PATCH v14 00/44] arm64: Support for Arm CCA in KVM Steven Price
2026-05-13 13:17 ` [PATCH v14 01/44] kvm: arm64: Include kvm_emulate.h in kvm/arm_psci.h Steven Price
2026-05-21 10:19 ` Marc Zyngier
2026-05-21 15:11 ` Steven Price
2026-05-13 13:17 ` [PATCH v14 02/44] kvm: arm64: Avoid including linux/kvm_host.h in kvm_pgtable.h Steven Price
2026-05-21 10:26 ` Marc Zyngier
2026-05-21 15:11 ` Steven Price
2026-05-13 13:17 ` [PATCH v14 03/44] arm64: RME: Handle Granule Protection Faults (GPFs) Steven Price
2026-05-21 12:25 ` Marc Zyngier
2026-05-21 15:15 ` Steven Price
2026-05-13 13:17 ` [PATCH v14 04/44] arm64: RMI: Add SMC definitions for calling the RMM Steven Price
2026-05-18 7:08 ` Gavin Shan
2026-05-20 16:01 ` Steven Price
2026-05-21 12:40 ` Marc Zyngier
2026-05-21 14:50 ` Suzuki K Poulose
2026-05-21 15:33 ` Steven Price
2026-05-22 9:58 ` Marc Zyngier
2026-06-03 10:15 ` Steven Price
2026-05-13 13:17 ` [PATCH v14 05/44] arm64: RMI: Add wrappers for RMI calls Steven Price
2026-05-19 5:35 ` Aneesh Kumar K.V
2026-05-21 15:44 ` Steven Price
2026-05-21 0:21 ` Gavin Shan
2026-05-21 15:44 ` Steven Price
2026-05-21 12:49 ` Marc Zyngier
2026-05-21 15:44 ` Steven Price
2026-05-13 13:17 ` [PATCH v14 06/44] arm64: RMI: Check for RMI support at init Steven Price
2026-05-21 0:39 ` Gavin Shan
2026-05-21 15:49 ` Steven Price
2026-05-25 6:58 ` Gavin Shan
2026-06-03 10:57 ` Steven Price
2026-05-21 13:02 ` Marc Zyngier
2026-06-03 10:57 ` Steven Price
2026-05-13 13:17 ` [PATCH v14 07/44] arm64: RMI: Configure the RMM with the host's page size Steven Price
2026-05-21 0:51 ` Gavin Shan
2026-05-21 22:36 ` Suzuki K Poulose
2026-05-21 13:30 ` Marc Zyngier
2026-05-21 14:53 ` Suzuki K Poulose
2026-06-03 15:48 ` Steven Price
2026-05-13 13:17 ` [PATCH v14 08/44] arm64: RMI: Ensure that the RMM has GPT entries for memory Steven Price
2026-05-19 5:55 ` Aneesh Kumar K.V
2026-06-03 15:48 ` Steven Price
2026-05-21 0:58 ` Gavin Shan
2026-06-03 15:48 ` Steven Price
2026-05-21 13:47 ` Marc Zyngier
2026-05-21 14:24 ` Marc Zyngier
2026-05-21 15:39 ` Suzuki K Poulose
2026-06-03 15:48 ` Steven Price
2026-05-13 13:17 ` [PATCH v14 09/44] arm64: RMI: Provide functions to delegate/undelegate ranges of memory Steven Price
2026-05-21 13:59 ` Marc Zyngier
2026-05-21 16:01 ` Suzuki K Poulose
2026-05-22 10:02 ` Marc Zyngier
2026-06-04 14:43 ` Steven Price
2026-05-13 13:17 ` [PATCH v14 10/44] arm64: RMI: Add support for SRO Steven Price
2026-05-14 8:01 ` Aneesh Kumar K.V
2026-05-14 9:33 ` Steven Price
2026-05-19 6:02 ` Aneesh Kumar K.V
2026-06-04 15:19 ` Steven Price
2026-05-21 4:38 ` Gavin Shan
2026-06-04 15:19 ` Steven Price
2026-05-21 14:35 ` Marc Zyngier
2026-06-04 15:19 ` Steven Price
2026-05-13 13:17 ` [PATCH v14 11/44] arm64: RMI: Check for RMI support at KVM init Steven Price
2026-05-13 13:17 ` [PATCH v14 12/44] arm64: RMI: Check for LPA2 support Steven Price
2026-05-13 13:17 ` [PATCH v14 13/44] arm64: RMI: Define the user ABI Steven Price
2026-05-26 22:17 ` Wei-Lin Chang
2026-06-04 15:27 ` Steven Price [this message]
2026-05-27 15:21 ` Marc Zyngier
2026-06-02 11:15 ` Suzuki K Poulose
2026-06-04 15:27 ` Steven Price
2026-05-13 13:17 ` [PATCH v14 14/44] arm64: RMI: Basic infrastructure for creating a realm Steven Price
2026-05-19 6:31 ` Aneesh Kumar K.V
2026-05-28 7:10 ` Marc Zyngier
2026-06-02 14:49 ` Suzuki K Poulose
2026-06-04 15:55 ` Steven Price
2026-05-13 13:17 ` [PATCH v14 15/44] kvm: arm64: Don't expose unsupported capabilities for realm guests Steven Price
2026-05-13 13:17 ` [PATCH v14 16/44] KVM: arm64: Allow passing machine type in KVM creation Steven Price
2026-05-13 13:17 ` [PATCH v14 17/44] arm64: RMI: RTT tear down Steven Price
2026-05-19 6:54 ` Aneesh Kumar K.V
2026-05-26 22:27 ` Wei-Lin Chang
2026-05-26 22:32 ` Wei-Lin Chang
2026-05-13 13:17 ` [PATCH v14 18/44] arm64: RMI: Activate realm on first VCPU run Steven Price
2026-05-13 13:17 ` [PATCH v14 19/44] arm64: RMI: Allocate/free RECs to match vCPUs Steven Price
2026-05-26 22:39 ` Wei-Lin Chang
2026-05-13 13:17 ` [PATCH v14 20/44] arm64: RMI: Support for the VGIC in realms Steven Price
2026-05-28 4:07 ` Gavin Shan
2026-05-13 13:17 ` [PATCH v14 21/44] KVM: arm64: Support timers in realm RECs Steven Price
2026-05-28 4:11 ` Gavin Shan
2026-05-13 13:17 ` [PATCH v14 22/44] arm64: RMI: Handle realm enter/exit Steven Price
2026-05-28 4:38 ` Gavin Shan
2026-05-13 13:17 ` [PATCH v14 23/44] arm64: RMI: Handle RMI_EXIT_RIPAS_CHANGE Steven Price
2026-05-19 9:40 ` Aneesh Kumar K.V
2026-05-27 10:52 ` Wei-Lin Chang
2026-05-13 13:17 ` [PATCH v14 24/44] KVM: arm64: Handle realm MMIO emulation Steven Price
2026-05-28 5:03 ` Gavin Shan
2026-05-13 13:17 ` [PATCH v14 25/44] KVM: arm64: Expose support for private memory Steven Price
2026-05-13 13:17 ` [PATCH v14 26/44] arm64: RMI: Allow populating initial contents Steven Price
2026-05-28 5:30 ` Gavin Shan
2026-05-13 13:17 ` [PATCH v14 27/44] arm64: RMI: Set RIPAS of initial memslots Steven Price
2026-05-19 10:02 ` Aneesh Kumar K.V
2026-05-19 10:13 ` Suzuki K Poulose
2026-05-19 12:55 ` Aneesh Kumar K.V
2026-05-19 13:06 ` Suzuki K Poulose
2026-05-13 13:17 ` [PATCH v14 28/44] arm64: RMI: Create the realm descriptor Steven Price
2026-05-26 22:47 ` Wei-Lin Chang
2026-05-28 5:51 ` Gavin Shan
2026-05-13 13:17 ` [PATCH v14 29/44] arm64: RMI: Runtime faulting of memory Steven Price
2026-05-13 13:17 ` [PATCH v14 30/44] KVM: arm64: Handle realm VCPU load Steven Price
2026-05-13 13:17 ` [PATCH v14 31/44] KVM: arm64: Validate register access for a Realm VM Steven Price
2026-05-13 13:17 ` [PATCH v14 32/44] KVM: arm64: Handle Realm PSCI requests Steven Price
2026-05-28 6:55 ` Gavin Shan
2026-05-13 13:17 ` [PATCH v14 33/44] KVM: arm64: WARN on injected undef exceptions Steven Price
2026-05-13 13:17 ` [PATCH v14 34/44] arm64: RMI: allow userspace to inject aborts Steven Price
2026-05-13 13:17 ` [PATCH v14 35/44] arm64: RMI: support RSI_HOST_CALL Steven Price
2026-05-13 13:17 ` [PATCH v14 36/44] arm64: RMI: Allow checking SVE on VM instance Steven Price
2026-05-13 13:17 ` [PATCH v14 37/44] arm64: RMI: Prevent Device mappings for Realms Steven Price
2026-05-19 10:25 ` Aneesh Kumar K.V
2026-05-13 13:17 ` [PATCH v14 38/44] arm64: RMI: Propagate number of breakpoints and watchpoints to userspace Steven Price
2026-05-13 13:17 ` [PATCH v14 39/44] arm64: RMI: Set breakpoint parameters through SET_ONE_REG Steven Price
2026-05-13 13:17 ` [PATCH v14 40/44] arm64: RMI: Propagate max SVE vector length from RMM Steven Price
2026-05-13 13:17 ` [PATCH v14 41/44] arm64: RMI: Configure max SVE vector length for a Realm Steven Price
2026-05-13 13:17 ` [PATCH v14 42/44] arm64: RMI: Provide register list for unfinalized RMI RECs Steven Price
2026-05-13 13:17 ` [PATCH v14 43/44] arm64: RMI: Provide accurate register list Steven Price
2026-05-13 13:17 ` [PATCH v14 44/44] arm64: RMI: Enable realms to be created Steven Price
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