Re: [Xen-devel] ioperm problem

Jeremy Fitzhardinge
Thu, 17 Nov 2011 18:05:57 -0000

On 11/17/2011 09:30 AM, Konrad Rzeszutek Wilk wrote:
> On Thu, Nov 17, 2011 at 08:56:34AM -0500, Ben Guthro wrote:
>> Attached is our patch to work around issues with the ioports with
>> some older nVidia cards.
>>
>> This, admittedly is a bit of a hack, and not exactly something that
>> I would see upstream wanting to carry, for a variety of reasons. It
>> really should all be predicated on whether the kernel is the initial
>> domain, etc.
>>
>> This opens up the legacy VGA ports in the VGA arbiter code.
> Was there a userspace program that did this? As in it would
> call ioperm?
>
>> Konrad - I think that you had suggested an alternate way of doing
>> this, IIRC, but I can''t seem to find it in my inbox. Due to
>> competing demands, and my nVidia hardware disappearing, I never went
>> back to rework this code.
> Ah, I might have some code that I just uncovered from Jeremy''s old
> git tree.
>
> I''ve put it up on devel/ioperm - it nicely wraps the ioperm
> call to go the native or paravirt.

Yeah, I''d sort of let that sit, since there''s nothing in a
"modern"
system which should require it.  Allowing usermode to poke at ioports
from within a domain is inherently suspect, after all.

    J