On Fri, Dec 25, 2015 at 9:43 PM, Zir Blazer <zir_bla...@hotmail.com> wrote:

> In a hypothetical case that I drop such Dual GPU card in a slot attached
> to the Chipset, it means that I would get isolation there, but not if
> connected to the Processor. Is that correct, too?
>

I'm not sure how to phrase it differently that I have in my blog post, each
interconnect component, whether a root port, switch port, or multifunction
device, needs to support ACS or ACS-equivalent isolation to have separate
IOMMU groups.  Isolation is lost at the furthest upstream device lacking
ACS.  In your scenario, yes, if the chipset root ports support
ACS-equivalent isolation and the switch supports native ACS, then isolation
is present through the downstream switch ports.  Nvidia GRID cards make use
of such switches and when installed into a downstream port supporting
isolation, each GPU is exposed within its own IOMMU group.  Thanks,

Alex
_______________________________________________
vfio-users mailing list
vfio-users@redhat.com
https://www.redhat.com/mailman/listinfo/vfio-users

Reply via email to