On Tue, Jul 27, 2021 at 08:04:16AM +0200, Cornelia Huck wrote: > 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. If it is a dedicated eventfd for 'device being removed' why is it in the CCW implementation and not core code? Is PCI doing the same? Jason
