[PATCH v4 16/17] KVM: arm64: Allow userspace to request KVM_ARM_VCPU_EL2*

[Marc Zyngier <maz@kernel.org>]

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>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/kvm_host.h | 2 +-
 arch/arm64/kvm/arm.c              | 6 ++++++
 include/uapi/linux/kvm.h          | 2 ++
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index b2c535036a06b..79e175a16d356 100644
--- 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 5287435873609..b021ce1e42c5c 100644
--- 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 b6ae8ad8934b5..c9d4a908976e8 100644
--- 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;
-- 
2.39.2