To provide a uniform way to check for KVM SVE support amongst other
features, this patch adds a suitable capability KVM_CAP_ARM_SVE,
and reports it as present when SVE is available.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
---
 arch/arm64/kvm/reset.c   | 8 ++++++++
 include/uapi/linux/kvm.h | 1 +
 2 files changed, 9 insertions(+)

diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index e67cd2e..f636b34 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c

@@ -35,6 +35,7 @@
 #include <asm/kvm_asm.h>
 #include <asm/kvm_coproc.h>
 #include <asm/kvm_mmu.h>
+#include <asm/virt.h>
 
 /* Maximum phys_shift supported for any VM on this host */
 static u32 kvm_ipa_limit;

@@ -93,6 +94,9 @@ int kvm_arch_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_ARM_VM_IPA_SIZE:
 		r = kvm_ipa_limit;
 		break;
+	case KVM_CAP_ARM_SVE:
+		r = system_supports_sve();
+		break;
 	default:
 		r = 0;
 	}

@@ -105,6 +109,10 @@ static int kvm_reset_sve(struct kvm_vcpu *vcpu)
 	if (!system_supports_sve())
 		return -EINVAL;
 
+	/* Verify that KVM startup enforced this when SVE was detected: */
+	if (WARN_ON(!has_vhe()))
+		return -EINVAL;