Re: [PATCH RFC 00/15] Add VFIO mediated device support and IMS support for the idxd driver.

Jason Gunthorpe
2020-04-23T19:49:51Z

On Thu, Apr 23, 2020 at 12:17:50PM -0700, Dan Williams wrote:

> Per Megha's follow-up can you send the details about that other device
> and help clear a path for a device-specific MSI addr/data table
> format. Ever since HMM I've been sensitive, perhaps overly-sensitive,
> to claims about future upstream users. The fact that you have an
> additional use case is golden for pushing this into a common area and
> validating the scope of the proposed API.

I think I said it at plumbers, but yes, we are interested in this, and
would like dynamic MSI-like interrupts available to the driver (what
Intel calls IMS)

It is something easy enough to illustrate with any RDMA device really,
just open a MR against the addr and use RDMA_WRITE to trigger the
data. It should trigger a Linux IRQ. Nothing else should be needed.

Jason