[PATCH v2 27/30] KVM: x86: hyper-v: Honor HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED bit

[Vitaly Kuznetsov]

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@xxxxxxxxxx>
---
 arch/x86/kvm/hyperv.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index ba5af4d27ccf..4ad27e7cdb05 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2046,11 +2046,19 @@ 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;
-- 
2.31.1