KVM: x86: hyper-v: Honor HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED bit

Hypercalls which use extended processor masks are only available when
HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED privilege bit is exposed (and
'RECOMMENDED' is rather a misnomer).
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210521095204.2161214-28-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/hyperv.c

@@ -2114,11 +2114,19 @@ static bool hv_check_hypercall_access(struct kvm_vcpu_hv *hv_vcpu, u16 code)
 			hv_vcpu->cpuid_cache.features_ebx & HV_DEBUGGING;
 	case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX:
 	case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX:
+		if (!(hv_vcpu->cpuid_cache.enlightenments_eax &
+		      HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
+			return false;
+		fallthrough;
 	case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST:
 	case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE:
 		return hv_vcpu->cpuid_cache.enlightenments_eax &
 			HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED;
 	case HVCALL_SEND_IPI_EX:
+		if (!(hv_vcpu->cpuid_cache.enlightenments_eax &
+		      HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
+			return false;
+		fallthrough;
 	case HVCALL_SEND_IPI:
 		return hv_vcpu->cpuid_cache.enlightenments_eax &
 			HV_X64_CLUSTER_IPI_RECOMMENDED;