Re: [PATCH v5 00/13] Copy Offload in NVMe Fabrics with P2P PCI Memory

From: Jerome Glisse
Date: Thu Aug 30 2018 - 15:20:21 EST

On Thu, Aug 30, 2018 at 12:53:39PM -0600, Logan Gunthorpe wrote:


> When the PCI P2PDMA config option is selected the ACS bits in every
> bridge port in the system are turned off to allow traffic to
> pass freely behind the root port. At this time, the bit must be disabled
> at boot so the IOMMU subsystem can correctly create the groups, though
> this could be addressed in the future. There is no way to dynamically
> disable the bit and alter the groups.

Can you provide an example on how to test this ? Like kernel command
line option, the doc patch does not have any such example. It would be
nice to add.

Maybe i have miss it in some of the patch. I just skimmed over for