Registry Services

Virtual devices can open, read, write, create, and delete registry keys and values using the registry services provide by the VMM. There are these registry services:

_GetRegistryKey

_GetRegistryPath

_RegCloseKey

_RegCreateKey

_RegDeleteKey

_RegDeleteValue

_RegEnumKey

_RegEnumValue

_RegFlushKey

_RegOpenKey

_RegQueryValue

_RegQueryValueEx

_RegSetValue

_RegSetValueEx

During the protected-mode initialization phases, the registry may be written to but the data will not be flushed to disk until the end of the Device_Init phase. Until the end of this phase, virtual devices may only access the HKEY_LOCAL_MACHINE key. No other predefined keys are available.

The registry services can be called from either assembly-language or C-language source in a VxD. To call the registry from a Ring 3 driver or application, refer to the SDK documentation for Win32 registry services. Assembly-language calls have this form:

include vmmreg.inc

< VMMCall _RegCloseKey    <phKey>
< cmp     eax,ERROR_SUCCESS
< jnz     CreateFail

C-language calls have this from:

include <vmmreg.h>

< if (VMM_RegCloseKey(phKey) != ERROR_SUCCESS) {
<     MyErrorHandler("RegCloseKey Failed");
< }