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include vmm.inc
 
VMMcall _GetAppFlatDSAlias
 
mov     [FlatData], eax         ; read-only GDT selector
 
The _GetAppFlatDSAlias service returns a ring-3, read-only, GDT selector
that provides access to the same memory as the system's ring-0 data segment
selector. Virtual devices use this service to support protected-mode APIs
that let protected-mode applications read from the same memory as the
virtual device.
 
This service has no parameters.
 
Return Value
 
The EAX register contains the selector.
 
Comments
 
Since more than one virtual device may use this selector, a virtual device
must never attempt to free the selector using the _Free_GDT_Selector
service. Also, a virtual device should not attempt to create a read/write
selector using this selector. If a virtual device requires an application to
write to any portion of system memory, the virtual device should build its
own selector with a base and limit that specifies just the memory the
application must modify.
 
Uses
 
EAX
 
See Also
 
_Free_GDT_Selector
 
 
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