Do Macs support VT-d?

Discussion in 'MacBook Pro' started by Faize, Feb 5, 2013.

  1. macrumors member

    Joined:
    Sep 23, 2011
    #1
    I often see others use VT-d as a justification to convince someone to get the higher end Retina MBP instead of the base model, but do Macs even support VT-d?
     
  2. macrumors G4

    Joined:
    Oct 23, 2010
    #2
    I don't believe Parallels Desktop or VMWare Fusion support VT-d.
     
  3. macrumors 6502a

    duervo

    Joined:
    Feb 5, 2011
    #3
    That's a pretty poor justification. There are a lot more valid reasons to justify the purchase than whether or not you can take advantage of VT-d.

    Also, you'd have to run a Type 1 hypervisor to take advantage of VT-d. Hyper-V, ESXi, KVM, XenServer, for example.

    Seems a waste of such a high quality display to use for a text console-based OS like Hyper-V (core install), ESXi, etc..
     
  4. macrumors G5

    jav6454

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    #4
    Yes they do. That is a reason why Fusion and Parallels work flawlessly.
     
  5. macrumors 6502a

    duervo

    Joined:
    Feb 5, 2011
    #5
    Interesting. So, exactly how would one go about exposing a PCIe device (i.e.: a dedicated graphics card), for example, to a Guest OS in a virtual machine running on Parallels or Fusion?
     
  6. macrumors G5

    jav6454

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    #6
    The virtual machine is in charge of that. You'll need to use the hardware options. For instance, in VMWare you can allow the maximum number of cores the Guest OS can have access so. Same with amount of RAM and HDD space.
     
  7. macrumors 6502a

    duervo

    Joined:
    Feb 5, 2011
    #7
    That's not the same as PCI passthrough, though.

    I just did some digging, and it appears that Parallels Workstation Extreme can in fact do PCI device passthrough. So, my initial response was not entirely accurate. That's not a consumer product though. Parallels Desktop, which is their consumer product, doesn't have this capability. Neither does Fusion.

    VT-d gives you the ability to passthrough (for example) your graphics card to the guest OS. The guest will see it as the actual card, instead of something such as "VMware SVGA".
     
  8. macrumors G5

    jav6454

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    #8
    I told you, that depends on the Virtual Software, I just cited some examples. Now, can they do it? I couldn't answer that.
     
  9. macrumors G4

    Joined:
    Oct 23, 2010
    #9
    But they also seem to work flawlessly on Macs such as mine (base 13" rMBP) that don't support VT-d.
     
  10. macrumors 6502a

    duervo

    Joined:
    Feb 5, 2011
    #10
    VT-d is not the same thing as VT-x. I believe that you're getting the two of them mixed up.

    No matter. I learned about Parallels Workstation Extreme tonight, so it's all good. :)
     
  11. jav6454, Feb 5, 2013
    Last edited: Feb 5, 2013

    macrumors G5

    jav6454

    Joined:
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    #11
    [size=3=]NVM[/size]

    ----------

    I think you are right, let me check up.


    EDIT - Yes, you are right, got 'em confused. Please disregard any comments on VT-d
     
  12. vatter69, Feb 6, 2013
    Last edited: Feb 6, 2013

    macrumors regular

    Joined:
    Feb 4, 2013
    #12
    Retina 13" CPU - i5 vs i7

    If you scroll down, you will notice that contrary to the i5, the i7 supports VT-d

    So if i understand that correctly, assuming you are running alot of VM/Parallels for Win8 or similar, the i7 would be the better choice, not only for it's higher base clock and larger cache.

    Which brings me to my next question - is the current Retina able so support VT-d if powered by an i7 or are there other culprits like the EFI/OS support for this?

    Finally - i wasn't able to verify whether VM-Ware Fusion even supports this feature. For Parellels you'd require Workstation Extreme as far as i can tell - does anyone have a link here or can tell from experience?

    Someone above posted no, only Extreme edition which confirms my own findings.

    Are there any performance comparisons between VT-d enabled VM and without? Or is this just marketing crap from Intel?

    Edit - just saw that Extreme Edition only works for Windows hosts so unless im mistaken, all this is a moot point anyways due to lack of proper support.
     
  13. macrumors 6502a

    Joined:
    Sep 17, 2007
    #13
    If one truly needed VT-d, they'd probably be setting up a powerful server running a type 1 hypervisor (i.e. a hypervisor that runs on bare metal and not inside a host OS like Parallels/Fusion do) with several VMs.

    If the question really is, will a MacBook without VT-d run one or more Windows VMs (or Linux, etc) in Parallels/Fusion/VirtualBox well? The answer is most definitely yes. If another question is, will having VT-d give me anything else? If you don't know the answer to that, then the answer is no.
     
  14. macrumors 6502a

    duervo

    Joined:
    Feb 5, 2011
    #14
    VT-d also requires chipset support. I'm not sure if the mobile Intel 7 series chipset supports it, and I'm too lazy to look it up on Intel's site right now.

    I noticed that about Parallels Extreme as well ... Windows and Linux only. No OS X support. Indeed, the point is moot.

    There are valid performance comparisons because the hardware is passed through the virtualization layer. The actual hardware itself is exposed to the guest OS, so it doesn't suffer from the overhead that it normally would if it were virtualized. However, performance is not the only reason for VT-d. Another example of its usefulness is to be able to do things like pass-through a legacy PCI serial adapter, modem, or USB controller to the guest OS for any legacy application that may need it (i.e.: USB security dongles,) enabling those places to virtualize those legacy apps that they previously couldn't without VT-d.

    The biggest caveat to VT-d is that getting Customer Support from Parallels, Microsoft, or VMware, etc. if you have issues with it is rather spotty at best. If you run into problems trying to pass-through a device, they will try to help you, but they make no explicit guarantees that it will work with every PCI device. In other words, "best effort" support is all you end up getting from them.
     
  15. macrumors 65816

    Joined:
    Mar 13, 2012
    #15
    Other laptops offer VT-d (Lenovo ThinkPad T430 and others), so the chipset does indeed support it. Just nothing on the Mac side seems to support it (i.e. no VM software is offered with VT-d support on OS X).
     
  16. Faize, Feb 6, 2013
    Last edited: Feb 6, 2013

    thread starter macrumors member

    Joined:
    Sep 23, 2011
    #16
    Perhaps I should have been more explicit: I'm not asking whether or not OS X can take advantage of VT-d, I'm asking whether or not the chipset and EFI implementation Apple uses in Macs supports VT-d.

    As for me personally, I want to know because one interesting piece of software that I've started using recently is XenClient. It has nothing to do with OS X (I'm pretty sure OS X isn't even a supported guest), but it won't run if the system doesn't support VT-d.

    Parallels Workstation Extreme requires Quadros (IIRC Nvidia sponsored the development cycle of Parallels Workstation Extreme in some way, so FirePros aren't supported...) so it wouldn't work on a MBP even if there was an OS X version.

    I agree that it's a pretty poor justification, but I suspect that the people making those recommendations don't understand what VT-d is and what it enables as opposed to VT-x. People who aren't eyeballs deep in virtualization tend to just think that VT is VT and all VT is the same.
     
  17. macrumors 6502a

    duervo

    Joined:
    Feb 5, 2011
    #17
    Well, crap. That is interesting. Now I'm going to have to put that one on my todo list to check out ... like it doesn't already have enough on it.
     

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