vmbus: Print a warning when enabled without the recommended set of features
Some Windows versions crash at boot or fail to enable the VMBus device if
they don't see the expected set of Hyper-V features (enlightenments).
Since this provides poor user experience let's warn user if the VMBus
device is enabled without the recommended set of Hyper-V features.
The recommended set is the minimum set of Hyper-V features required to make
the VMBus device work properly in Windows Server versions 2016, 2019 and
2022.
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
diff --git a/hw/hyperv/hyperv.c b/hw/hyperv/hyperv.c
index 6c4a18d..3ea54ba 100644
--- a/hw/hyperv/hyperv.c
+++ b/hw/hyperv/hyperv.c
@@ -951,3 +951,15 @@
return msg.u.query_options.options;
}
+
+static bool vmbus_recommended_features_enabled;
+
+bool hyperv_are_vmbus_recommended_features_enabled(void)
+{
+ return vmbus_recommended_features_enabled;
+}
+
+void hyperv_set_vmbus_recommended_features_enabled(void)
+{
+ vmbus_recommended_features_enabled = true;
+}
diff --git a/hw/hyperv/vmbus.c b/hw/hyperv/vmbus.c
index 380239a..f33afee 100644
--- a/hw/hyperv/vmbus.c
+++ b/hw/hyperv/vmbus.c
@@ -2631,6 +2631,12 @@
return;
}
+ if (!hyperv_are_vmbus_recommended_features_enabled()) {
+ warn_report("VMBus enabled without the recommended set of Hyper-V features: "
+ "hv-stimer, hv-vapic and hv-runtime. "
+ "Some Windows versions might not boot or enable the VMBus device");
+ }
+
bridge->bus = VMBUS(qbus_new(TYPE_VMBUS, dev, "vmbus"));
}
diff --git a/include/hw/hyperv/hyperv.h b/include/hw/hyperv/hyperv.h
index 015c352..d717b4e 100644
--- a/include/hw/hyperv/hyperv.h
+++ b/include/hw/hyperv/hyperv.h
@@ -139,4 +139,8 @@
} HvSynDbgMsg;
typedef uint16_t (*HvSynDbgHandler)(void *context, HvSynDbgMsg *msg);
void hyperv_set_syndbg_handler(HvSynDbgHandler handler, void *context);
+
+bool hyperv_are_vmbus_recommended_features_enabled(void);
+void hyperv_set_vmbus_recommended_features_enabled(void);
+
#endif
diff --git a/target/i386/kvm/hyperv-stub.c b/target/i386/kvm/hyperv-stub.c
index 778ed78..3263dcf 100644
--- a/target/i386/kvm/hyperv-stub.c
+++ b/target/i386/kvm/hyperv-stub.c
@@ -52,3 +52,7 @@
void hyperv_x86_synic_update(X86CPU *cpu)
{
}
+
+void hyperv_x86_set_vmbus_recommended_features_enabled(void)
+{
+}
diff --git a/target/i386/kvm/hyperv.c b/target/i386/kvm/hyperv.c
index 6825c89..f2a3fe6 100644
--- a/target/i386/kvm/hyperv.c
+++ b/target/i386/kvm/hyperv.c
@@ -149,3 +149,8 @@
return -1;
}
}
+
+void hyperv_x86_set_vmbus_recommended_features_enabled(void)
+{
+ hyperv_set_vmbus_recommended_features_enabled();
+}
diff --git a/target/i386/kvm/hyperv.h b/target/i386/kvm/hyperv.h
index 6754329..e3982c8 100644
--- a/target/i386/kvm/hyperv.h
+++ b/target/i386/kvm/hyperv.h
@@ -26,4 +26,6 @@
void hyperv_x86_synic_reset(X86CPU *cpu);
void hyperv_x86_synic_update(X86CPU *cpu);
+void hyperv_x86_set_vmbus_recommended_features_enabled(void);
+
#endif
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 42970ab..e68cbe9 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -1650,6 +1650,13 @@
}
}
+ /* Skip SynIC and VP_INDEX since they are hard deps already */
+ if (hyperv_feat_enabled(cpu, HYPERV_FEAT_STIMER) &&
+ hyperv_feat_enabled(cpu, HYPERV_FEAT_VAPIC) &&
+ hyperv_feat_enabled(cpu, HYPERV_FEAT_RUNTIME)) {
+ hyperv_x86_set_vmbus_recommended_features_enabled();
+ }
+
return 0;
}
