[RFC PATCH v6 06/35] KVM: arm64: Add KVM_ARM_VCPU_SPE VCPU feature

[Alexandru Elisei]

Add a new VCPU feature that enables SPE virtualization when set by
userspace.

Signed-off-by: Alexandru Elisei <alexandru.elisei at arm.com>
---
 arch/arm64/include/asm/kvm_spe.h  | 4 ++++
 arch/arm64/include/uapi/asm/kvm.h | 1 +
 arch/arm64/kvm/arm.c              | 7 +++++++
 3 files changed, 12 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_spe.h b/arch/arm64/include/asm/kvm_spe.h
index 6572384531e2..8e8a5c6f7971 100644
--- a/arch/arm64/include/asm/kvm_spe.h
+++ b/arch/arm64/include/asm/kvm_spe.h
@@ -13,8 +13,12 @@ static __always_inline bool kvm_supports_spe(void)
 {
 	return static_branch_likely(&kvm_spe_available);
 }
+
+#define vcpu_has_spe(vcpu)					\
+	(vcpu_has_feature(vcpu, KVM_ARM_VCPU_SPE))
 #else
 #define kvm_supports_spe()	false
+#define vcpu_has_spe(vcpu)	false
 #endif /* CONFIG_KVM_ARM_SPE */
 
 #endif /* __ARM64_KVM_SPE_H__ */
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index ed5f3892674c..5bdfe1f6d565 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_SPE		9 /* Support SPE in guest */
 
 struct kvm_vcpu_init {
 	__u32 target;
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index ee230cb34215..1e4449d96d62 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1459,6 +1459,9 @@ static unsigned long system_supported_vcpu_features(void)
 	if (!cpus_have_final_cap(ARM64_HAS_NESTED_VIRT))
 		clear_bit(KVM_ARM_VCPU_HAS_EL2, &features);
 
+	if (!kvm_supports_spe())
+		clear_bit(KVM_ARM_VCPU_SPE, &features);
+
 	return features;
 }
 
@@ -1498,6 +1501,10 @@ static int kvm_vcpu_init_check_features(struct kvm_vcpu *vcpu,
 	if (test_bit(KVM_ARM_VCPU_HAS_EL2, &features))
 		return -EINVAL;
 
+	/* SPE is incompatible with AArch32 */
+	if (test_bit(KVM_ARM_VCPU_SPE, &features))
+		return -EINVAL;
+
 	return 0;
 }
 
-- 
2.51.2