High rate of SMIs may cause a Hyper-V enabled system to hang at boot on Windows Server 2008 R2

Applies to: Windows Server 2008 R2 StandardWindows Server 2008 R2 EnterpriseWindows Server 2008 R2 Datacenter

Symptoms


Consider the following scenario:

You have a Windows Server 2008 R2 system with the Hyper-V role enabled.  If the BIOS has been set to inject SMIs at a high rate, 11 SMI/sec for example.  The system may hang during boot time.

Failure can also occur at lower frequencies (system hanging/slower boot time), but as the rate of SMI injections increases, the likelihood of failure (system hanging) increases.


Cause


If an SMI occurs before all processors are ready to receive SMIs, Windows boot will hang. 

Resolution


Reduce the rate of SMI injection in the BIOs to prevent a hang during Windows boot.

More Information


Production servers typically do not include BIOS setting for manually injecting SMIs. These setting would only be available in an OEM or BIOS vendor's testing environment.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.