On Mon, Jul 26 2021, Alex Williamson <alex.williamson@xxxxxxxxxx> wrote: > On Mon, 26 Jul 2021 20:09:06 -0300 > Jason Gunthorpe <jgg@xxxxxxxxxx> wrote: > >> On Mon, Jul 26, 2021 at 07:07:04PM +0200, Cornelia Huck wrote: >> >> > But I wonder why nobody else implements this? Lack of surprise removal? >> >> The only implementation triggers an eventfd that seems to be the same >> eventfd as the interrupt.. >> >> Do you know how this works in userspace? I'm surprised that the >> interrupt eventfd can trigger an observation that the kernel driver >> wants to be unplugged? > > I think we're talking about ccw, but I see QEMU registering separate > eventfds for each of the 3 IRQ indexes and the mdev driver specifically > triggering the req_trigger...? Thanks, > > Alex Exactly, ccw has a trigger for normal I/O interrupts, CRW (machine checks), and this one.
