KVM: arm64: Allow userspace to request KVM_ARM_VCPU_EL2*

Since we're (almost) feature complete, let's allow userspace to
request KVM_ARM_VCPU_EL2* by bumping KVM_VCPU_MAX_FEATURES up.

We also now advertise the features to userspace with new capabilities.

It's going to be great...

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Link: https://lore.kernel.org/r/20250514103501.2225951-17-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index b2c535036a06bbf88601ad59b297b25fd5b349d5..79e175a16d35691c9df7439dba85bf190bd5532e 100644 (file)
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -39,7 +39,7 @@
 
 #define KVM_MAX_VCPUS VGIC_V3_MAX_CPUS
 
-#define KVM_VCPU_MAX_FEATURES 7
+#define KVM_VCPU_MAX_FEATURES 9
 #define KVM_VCPU_VALID_FEATURES        (BIT(KVM_VCPU_MAX_FEATURES) - 1)
 
 #define KVM_REQ_SLEEP \

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 5287435873609ff5dab2245ee0e6a5f51db992e3..b021ce1e42c5c029531d6b5a1dccbad462171cba 100644 (file)
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -368,6 +368,12 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
        case KVM_CAP_ARM_EL1_32BIT:
                r = cpus_have_final_cap(ARM64_HAS_32BIT_EL1);
                break;
+       case KVM_CAP_ARM_EL2:
+               r = cpus_have_final_cap(ARM64_HAS_NESTED_VIRT);
+               break;
+       case KVM_CAP_ARM_EL2_E2H0:
+               r = cpus_have_final_cap(ARM64_HAS_HCR_NV1);
+               break;
        case KVM_CAP_GUEST_DEBUG_HW_BPS:
                r = get_num_brps();
                break;

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index b6ae8ad8934b52c7e779cd2e84b8330eb1de68bc..c9d4a908976e88b9d9964a5e07483be48e70319a 100644 (file)
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -930,6 +930,8 @@ 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_EL2 240
+#define KVM_CAP_ARM_EL2_E2H0 241
 
 struct kvm_irq_routing_irqchip {
        __u32 irqchip;