On 4/16/25 11:41 PM, Steven Price wrote:
There is one (multiplexed) CAP which can be used to create, populate and
then activate the realm.
Co-developed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Steven Price <steven.price@xxxxxxx>
---
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 | 70 +++++++++++++++++++++++++++++++
arch/arm64/include/uapi/asm/kvm.h | 49 ++++++++++++++++++++++
include/uapi/linux/kvm.h | 10 +++++
3 files changed, 129 insertions(+)
With below comment addressed:
Reviewed-by: Gavin Shan <gshan@xxxxxxxxxx>
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 1f8625b7646a..99ba6c82cf37 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -3527,6 +3527,11 @@ Possible features:
- the KVM_REG_ARM64_SVE_VLS pseudo-register is immutable, and can
no longer be written using KVM_SET_ONE_REG.
+ - KVM_ARM_VCPU_REC: Allocate a REC (Realm Execution Context) for this
+ VCPU. This must be specified on all VCPUs created in a Realm VM.
+ Depends on KVM_CAP_ARM_RME.
+ Requires KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_REC).
+
4.83 KVM_ARM_PREFERRED_TARGET
-----------------------------
@@ -5098,6 +5103,7 @@ Recognised values for feature:
===== ===========================================
arm64 KVM_ARM_VCPU_SVE (requires KVM_CAP_ARM_SVE)
+ arm64 KVM_ARM_VCPU_REC (requires KVM_CAP_ARM_RME)
===== ===========================================
Finalizes the configuration of the specified vcpu feature.
@@ -6452,6 +6458,30 @@ the capability to be present.
`flags` must currently be zero.
+4.144 KVM_ARM_VCPU_RMM_PSCI_COMPLETE
+------------------------------------
+
+:Capability: KVM_CAP_ARM_RME
+:Architectures: arm64
+:Type: vcpu ioctl
+:Parameters: struct kvm_arm_rmm_psci_complete (in)
+:Returns: 0 if successful, < 0 on error
+
+::
+
+ struct kvm_arm_rmm_psci_complete {
+ __u64 target_mpidr;
+ __u32 psci_status;
+ __u32 padding[3];
+ };
+
+Where PSCI functions are handled by user space, the RMM needs to be informed of
+the target of the operation using `target_mpidr`, along with the status
+(`psci_status`). The RMM v1.0 specification defines two functions that require
+this call: PSCI_CPU_ON and PSCI_AFFINITY_INFO.
+
+If the kernel is handling PSCI then this is done automatically and the VMM
+doesn't need to call this ioctl.
.. _kvm_run:
@@ -8280,6 +8310,46 @@ aforementioned registers before the first KVM_RUN. These registers are VM
scoped, meaning that the same set of values are presented on all vCPUs in a
given VM.
+7.38 KVM_CAP_ARM_RME
+--------------------
+
+:Architectures: arm64
+:Target: VM
+:Parameters: args[0] provides an action, args[1] points to a structure in
+ memory for some actions.
+:Returns: 0 on success, negative value on error
+
+Used to configure and set up the memory for a Realm. The available actions are:
+
+================================= =============================================
+ KVM_CAP_ARM_RME_CONFIG_REALM Takes struct arm_rme_config as args[1] and
+ configures realm parameters prior to it being
+ created.
+
+ Options are ARM_RME_CONFIG_RPV to set the
+ "Realm Personalization Value" and
+ ARM_RME_CONFIG_HASH_ALGO to set the hash
+ algorithm.
+
+ KVM_CAP_ARM_RME_CREATE_REALM Request the RMM create the realm. The realm's
+ configuration parameters must be set first.
+
+ KVM_CAP_ARM_RME_INIT_RIPAS_REALM Takes struct arm_rme_init_ripas as args[1]
+ and sets the RIPAS (Realm IPA State) to
+ RIPAS_RAM of a specified area of the realm's
+ IPA.
+
+ KVM_CAP_ARM_RME_POPULATE_REALM Takes struct arm_rme_init_ripas as args[1]
+ and populates a region of protected address
+ space by copying the data from the shared
+ alias.
+
+ KVM_CAP_ARM_RME_ACTIVATE_REALM Request the RMM activate the realm. No
+ further changes can be made to the realm's
+ configuration, and VCPUs are not permitted to
+ enter the realm until it has been activated.
^^^^^^^^^^^^^^^^^^
s/has been activated/is deactivated
I don't see where the guard is applied to prevent vCPU is added after realm
has been activated. I may missed that. Otherwise, it's something to be improved
n the subsequent patch where a vCPU is created and added to the realm.
+================================= =============================================
+
8. Other capabilities.
======================
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index af9d9acaf997..b57712880605 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -106,6 +106,7 @@ struct kvm_regs {
#define KVM_ARM_VCPU_PTRAUTH_GENERIC 6 /* VCPU uses generic authentication */
#define KVM_ARM_VCPU_HAS_EL2 7 /* Support nested virtualization */
#define KVM_ARM_VCPU_HAS_EL2_E2H0 8 /* Limit NV support to E2H RES0 */
+#define KVM_ARM_VCPU_REC 9 /* VCPU REC state as part of Realm */
struct kvm_vcpu_init {
__u32 target;
@@ -429,6 +430,54 @@ enum {
#define KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES 3
#define KVM_DEV_ARM_ITS_CTRL_RESET 4
+/* KVM_CAP_ARM_RME on VM fd */
+#define KVM_CAP_ARM_RME_CONFIG_REALM 0
+#define KVM_CAP_ARM_RME_CREATE_REALM 1
+#define KVM_CAP_ARM_RME_INIT_RIPAS_REALM 2
+#define KVM_CAP_ARM_RME_POPULATE_REALM 3
+#define KVM_CAP_ARM_RME_ACTIVATE_REALM 4
+
+/* List of configuration items accepted for KVM_CAP_ARM_RME_CONFIG_REALM */
+#define ARM_RME_CONFIG_RPV 0
+#define ARM_RME_CONFIG_HASH_ALGO 1
+
+#define ARM_RME_CONFIG_MEASUREMENT_ALGO_SHA256 0
+#define ARM_RME_CONFIG_MEASUREMENT_ALGO_SHA512 1
+
+#define ARM_RME_CONFIG_RPV_SIZE 64
+
+struct arm_rme_config {
+ __u32 cfg;
+ union {
+ /* cfg == ARM_RME_CONFIG_RPV */
+ struct {
+ __u8 rpv[ARM_RME_CONFIG_RPV_SIZE];
+ };
+
+ /* cfg == ARM_RME_CONFIG_HASH_ALGO */
+ struct {
+ __u32 hash_algo;
+ };
+
+ /* Fix the size of the union */
+ __u8 reserved[256];
+ };
+};
+
+#define KVM_ARM_RME_POPULATE_FLAGS_MEASURE (1 << 0)
+struct arm_rme_populate_realm {
+ __u64 base;
+ __u64 size;
+ __u32 flags;
+ __u32 reserved[3];
+};
+
+struct arm_rme_init_ripas {
+ __u64 base;
+ __u64 size;
+ __u64 reserved[2];
+};
+
/* Device Control API on vcpu fd */
#define KVM_ARM_VCPU_PMU_V3_CTRL 0
#define KVM_ARM_VCPU_PMU_V3_IRQ 0
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index b6ae8ad8934b..0b8479985581 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -930,6 +930,7 @@ struct kvm_enable_cap {
#define KVM_CAP_X86_APIC_BUS_CYCLES_NS 237
#define KVM_CAP_X86_GUEST_MODE 238
#define KVM_CAP_ARM_WRITABLE_IMP_ID_REGS 239
+#define KVM_CAP_ARM_RME 240
struct kvm_irq_routing_irqchip {
__u32 irqchip;
@@ -1582,4 +1583,13 @@ struct kvm_pre_fault_memory {
__u64 padding[5];
};
+/* Available with KVM_CAP_ARM_RME, only for VMs with KVM_VM_TYPE_ARM_REALM */
+struct kvm_arm_rmm_psci_complete {
+ __u64 target_mpidr;
+ __u32 psci_status;
+ __u32 padding[3];
+};
+
+#define KVM_ARM_VCPU_RMM_PSCI_COMPLETE _IOW(KVMIO, 0xd6, struct kvm_arm_rmm_psci_complete)
+
#endif /* __LINUX_KVM_H */
Thanks,
Gavin
