Re: [PATCH v5 08/14] iommufd/viommu: Add iommufd_viommu_report_event helper

[Jason Gunthorpe]

On Wed, Jan 22, 2025 at 11:02:59PM -0800, Nicolin Chen wrote:

> I made a change to duplicate the overflow node in the fetch() that
> is protected by the spinlock, which is used for copy_to_user. Then
> the other routine for vEVENT reporting, protected by the spinlock,
> can race-freely update the preallocated overflow node.

That seems like the right answer, copy the few bytes you need on
the stack under the spinlock.

Jason