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Date: Tue, 2 Jan 2024 19:38:49 -0400
From: Jason Gunthorpe <jgg@nvidia.com>
To: Yi Liu <yi.l.liu@intel.com>
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Subject: Re: [PATCH v7 1/3] iommufd: Add data structure for Intel VT-d
 stage-1 cache invalidation
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On Fri, Dec 15, 2023 at 12:01:19PM +0800, Yi Liu wrote:
> > I think I misread Yi's narrative: dev_id is a working approach
> > for VMM to convert to a vRID, while he is asking for a better
> > alternative :)
> 
> In concept, dev_id works, but in reality we have problem to get a dev_id
> for a given device in intel iommu driver, hence I'm asking for help here. :)

I think we just need to solve this one way or another.. Even if you
use a viommu object you still end up having difficult coupling to
iommufd

Some:
  iommufd_get_dev_id(struct iommufd_ctx *ictx, struct device *dev)

Callable by a driver (using the driver-callable function
infrastructure we made for dirty tracking) Is really all that is
needed here.

Jason