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Subject[PATCH v2 24/30] KVM: x86: hyper-v: Honor HV_DEBUGGING privilege bit
Date
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@redhat.com>
---
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
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