Re: [PATCH v7 1/3] iommufd: Add data structure for Intel VT-d stage-1 cache invalidation

[Nicolin Chen <nicolinc@nvidia.com>]

On Wed, Jan 03, 2024 at 12:58:48PM -0400, Jason Gunthorpe wrote:
> On Wed, Jan 03, 2024 at 08:48:46AM -0800, Nicolin Chen wrote:
> > > You can pass the ctx to the invalidate op, it is already implied
> > > because the passed iommu_domain is linked to a single iommufd ctx.
> > 
> > The device virtual id lookup API needs something similar, yet it
> > likely needs a viommu pointer (or its id) instead? As the table
> > is attached to a viommu while an ictx can have multiple viommus,
> > right?
> 
> Yes, when we get to an API for that it will have to be some op
> 'invalidate_viommu(..)' and it can get the necessary pointers.

OK! I will try that first.

> The viommu object will have to be some driver object like the
> iommu_domain.

I drafted something like this, linking it to struct iommu_device:

+struct iommufd_viommu {
+       struct iommufd_object obj;
+       struct iommufd_ctx *ictx;
+       struct iommu_device *iommu_dev;
+       struct iommufd_hwpt_paging *hwpt;
+       /* array of struct iommufd_device, indexed by device virtual id */
+       struct xarray device_ids;
+};

Thanks
Nicolin