Re: [Qemu-devel] [Xen-devel] [v4][PATCH 2/5] xen, gfx passthrough: create intel isa bridge

[Sander Eikelenboom]

Tuesday, June 3, 2014, 2:24:40 PM, you wrote:

> Il 03/06/2014 14:21, Sander Eikelenboom ha scritto:
>>
>> The last part should perhaps be fixed in the driver/firmware (for instance
>> the assumption the device is always device 00:02.0, that's valid for real 
>> intel
>> hardware, but not necessary for passthrough or emulation). A requirement for
>> using the latest firmware/drivers for passthrough to work could be 
>> acceptable i
>> guess ?

> The problem is worse than that.  The assumptions are that the driver can 
> make choices based on the device/vendor IDs of 00:1f.0, and that the 
> driver can read/write to the config space of 00:00.0.

> Paolo

It's quite tempting to start making assumptions and shortcuts when writing 
drivers for 
hardware fixed in a platfrom (IGD's), they probably wouldn't have done that 
when they 
were also making seperate PCI(-e) graphic cards with these chips because it 
would blow up on all sorts of machines (which is what happens now when trying 
to 
pass it through (or emulate it) on another platform).

--
Sander