RE: [Xen-users] System seams slower with Xenified kernel and xend dies with SIG 15

["Petersson, Mats" <Mats.Petersson@xxxxxxx>]

> -----Original Message-----
> From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx 
> [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of 
> Gabriel Rossetti
> Sent: 01 August 2006 19:27
> To: xen-users@xxxxxxxxxxxxxxxxxxx
> Subject: [Xen-users] System seams slower with Xenified kernel 
> and xend dies with SIG 15
> 
> Hello all,
> 
>  I compiled the kernel with the xen patch and I seam to have trouble
> with some kernel modules, like ATI's proprietary driver. The system
> seams considerably slower than
> before, this might be because of the video drivers, or maybe the RAM
> alocated to dom0 (512Mb instead of it's usual 1Gb). When I try to run
> xend, it dies with a SIG 15.

Can't comment on xend dieing, but any binary driver would be unlikely to
work in Xenified kernel, since the Xenified kernel changes some of the
things that a driver needs to do when it translates memory addresses
from virtual to physical - there are now two different types of physical
address: pseudo-physical, which is what the OS sees, and machine
physical, which is what the PROCESSOR sees. If you have a Dom0 that has
512MB of RAM, it will not necessarily have all it's memory from
0..512MB, but it may actually be located anywhere Xen likes it to be...
[Dom0 is most likely starting somewhere low, since it's loaded early -
but that's just luck, rather than planned for]. Machine physical is
needed for the PCI (PCIe == PCIx == AGP == PCI in this case - they are
just different hardware implementations of the same protocol) so that
the card can access memory directly, and for sure all modern graphics
cards have direct memory access capabilities (and most likely doesn't do
much other than a standard 15 year old VGA card if you don't use these
capability). 


--
Mats



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