> From: Jason Gunthorpe <jgg@xxxxxxxxxx> > Sent: Wednesday, November 8, 2023 10:50 AM > > On Tue, Nov 07, 2023 at 04:06:41PM -0700, Alex Williamson wrote: > > > This driver that doesn't exist yet could implement its own SET_IRQS > > ioctl that backs MSI-X with IMS as a starting point. Presumably we > > expect multiple drivers to require this behavior, so common code makes > > sense, but the rest of us in the community can't really evaluate how > > much it makes sense to slice the common code without seeing that > > implementation and how it might leverage, if not directly use, the > > existing core code. > > I've been seeing a general interest in taking something that is not > MSI-X (eg "IMS" for IDXD) and converting it into MSI-X for the vPCI > function. I think this will be a durable need in this space. > > Ideally it will be overtaken by simply teaching the guest, vfio and > the hypervisor interrupt logic how to directly generate interrupts > with a guest controlled addr/data pair without requiring MSI-X > trapping. That is the fundamental reason why this has to be done this > convoluted way. > Even with that a legacy guest which doesn't support such enlightened way still needs this convoluted way. 😊 and for SIOV anyway the trap cannot be eliminated given the interrupt storage is shared by all vdev's.
