Re: Nvidia, Xen, and Vt-d

[Jeremy Fitzhardinge <jeremy@goop.org>]

On 09/09/09 01:56, Keir Fraser wrote:
> On 09/09/2009 09:47, "Michael J Coss" <mjcoss@alcatel-lucent.com> wrote:
>
>   
>> I've tried 3.4.1, and the lastest xen-unstable.  I've tried the pv-ops
>> git tree as I really need a 2.6.31 dom0 kernel for other reasons, but
>> for the moment I'd just like to get to the point where I have Xen, and
>> dom0 and Nvidia playing nicely with one another, so I can move on to
>> working on Vt-d and graphic pass through.
>>
>> Any suggestions?
>>     
> Unless you really must have 2.6.30+, I'd recommend the 2.6.27 tree and
> patchqueue from http://xenbits.xensource.com/XCI. Otherwise you are likely
> to have to get your hands fairly dirty with pv_ops. For example, afaik
> starting an X server on pv_ops is still pretty ambitious on some systems.
>   

Starting X in dom0 seems to work OK for Intel and ATI systems, at least;
I expect most DRM drivers would work OK if they're well-behaved because
we're hooking AGP memory accesses, etc.  However, the proprietary Nvidia
drivers are problematic, though I gather there are some patches floating
around for them.

Unfortunately the AGP hooks are being removed (some years after Keir
first added them, and just as they have a user according to their
original intent) in favour of making each driver use the DMA API to do
the appropriate phys<->bus conversions.  So far, only the Intel driver
has been converted, and only when Intel IOMMU is enabled.  However, I
didn't get any objection from the DRM folks about making it
unconditional or adding it to new drivers as needed.

    J