device passthrough

device passthrough

[Mu Lin]

Hi, All:

Is there any method to directly assign a device to Guest OS  without VT-d?

Thanks

Mu

Re: device passthrough

[Chris Wright]

* Mu Lin (mul@juniper.net) wrote:
> Is there any method to directly assign a device to Guest OS  without VT-d?

Assuming you mean a PCI device, no, there isn't.

Without an IOMMU[1] you can't directly assign a PCI device to a guest
(nor is it safe).  There have been patches floating around to allow
this, but they don't maintain secure isolation.

thanks,
-chris

[1] VT-d is an Intel chipset feature, so you could certainly do it on an
AMD platform that has an AMD IOMMU.

RE: device passthrough

[Mu Lin]

Thanks, Chris,

Do you know where is the patch, I just need something quick and dirty for now, my shining new board does have VT-d but the BIOS is not ready yet, I want to have something "working" now.

Mu 

> -----Original Message-----
> From: Chris Wright [mailto:chrisw@sous-sol.org] 
> Sent: Friday, May 28, 2010 12:33 PM
> To: Mu Lin
> Cc: kvm@vger.kernel.org
> Subject: Re: device passthrough
> 
> * Mu Lin (mul@juniper.net) wrote:
> > Is there any method to directly assign a device to Guest OS 
>  without VT-d?
> 
> Assuming you mean a PCI device, no, there isn't.
> 
> Without an IOMMU[1] you can't directly assign a PCI device to 
> a guest (nor is it safe).  There have been patches floating 
> around to allow this, but they don't maintain secure isolation.
> 
> thanks,
> -chris
> 
> [1] VT-d is an Intel chipset feature, so you could certainly 
> do it on an AMD platform that has an AMD IOMMU.
> 

Re: device passthrough

[Chris Wright]

* Mu Lin (mul@juniper.net) wrote:
> Do you know where is the patch, I just need something quick and dirty
> for now, my shining new board does have VT-d but the BIOS is not ready
> yet, I want to have something "working" now.

Sorry, I don't have a handy pointer.  You can search for either pv dma
changes (paravirtualizing the guest's request for dma addrs so that it
gets host physical addr to program card for dma) or reserved-ram for
pci-passthrough (1:1 mapping of guest to host physical memory).  I don't
recall a recent attempt to bring them forward, so expect anything you
find to be quite stale.

thanks,
-chris