Hyper-V partition must possess 'HV_DEBUGGING' privilege to issue HVCALL_POST_DEBUG_DATA/HVCALL_RETRIEVE_DEBUG_DATA/ HVCALL_RESET_DEBUG_SESSION hypercalls. Note, when SynDBG is disabled hv_check_hypercall_access() returns 'true' (like for any other unknown hypercall) so the result will be HV_STATUS_INVALID_HYPERCALL_CODE and not HV_STATUS_ACCESS_DENIED. Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> --- arch/x86/kvm/hyperv.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 523f63287636..36ec688cda4e 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -2035,6 +2035,15 @@ static bool hv_check_hypercall_access(struct kvm_vcpu_hv *hv_vcpu, u16 code) return hv_vcpu->cpuid_cache.features_ebx & HV_POST_MESSAGES; case HVCALL_SIGNAL_EVENT: return hv_vcpu->cpuid_cache.features_ebx & HV_SIGNAL_EVENTS; + case HVCALL_POST_DEBUG_DATA: + case HVCALL_RETRIEVE_DEBUG_DATA: + case HVCALL_RESET_DEBUG_SESSION: + /* + * Return 'true' when SynDBG is disabled so the resulting code + * will be HV_STATUS_INVALID_HYPERCALL_CODE. + */ + return !kvm_hv_is_syndbg_enabled(hv_vcpu->vcpu) || + hv_vcpu->cpuid_cache.features_ebx & HV_DEBUGGING; default: break; } -- 2.31.1
