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Assign pages to VT-D devices

steven765
Beginner
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Need some help understanding the theory of operation for implementing Vt-D.  I've been through the manual a couple of times.  The part I'm having trouble understanding is when we assign the page tables to the root complex structures.  How does the guest know which frames it's allowed to assign for DMA use?  The only work around I could think of is to either A do a VMCALL and ask, or B mirror the entire range the guest is allowed to access vie EPT and assign that to the root complex structure as well. 

 

 

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Quoc-Thai_L_Intel
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Here is a blog created to provide additional resources for sw developers: Resources for Software Developers: Intel® Virtualization Technology (Intel® VT). - Thai

 

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steven765
Beginner
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Thanks Thai, but unless I'm missing something that link only contains the specification.   The specification does not get into use cases for the hardware only how to configure individual pieces. Also the VT-D manual has a bunch of error's in the structure definitions. 

What myself and many other researcher's need is a background on how they intended the hardware to be used. A high level walk through of these are the bare minimum components needed to get it up and running.

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Quoc-Thai_L_Intel
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Hi, I found an article on VT-D topic for you.  It may provide some more information.   Intel® Virtualization Technology for Directed I/O (VT-d): Enhancing Intel platforms for efficient virtualization of I/O devices.

-Thai

 

 

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