> From: Alex Williamson <alex.williamson@xxxxxxxxxx> > Sent: Friday, October 7, 2022 2:31 AM > > On Thu, 6 Oct 2022 08:37:09 -0300 > Jason Gunthorpe <jgg@xxxxxxxxxx> wrote: > > > On Wed, Oct 05, 2022 at 04:03:56PM -0600, Alex Williamson wrote: > > > We can't have a .remove callback that does nothing, this breaks > > > removing the device while it's in use. Once we have the > > > vfio_unregister_group_dev() fix below, we'll block until the device is > > > unused, at which point vgpu->attached becomes false. Unless I'm > > > missing something, I think we should also follow-up with a patch to > > > remove that bogus warn-on branch, right? Thanks, > > > > Yes, looks right to me. > > > > I question all the logical arround attached, where is the locking? > > Zhenyu, Zhi, Kevin, > > Could someone please take a look at use of vgpu->attached in the GVT-g > driver? It's use in intel_vgpu_remove() is bogus, the .release > callback needs to use vfio_unregister_group_dev() to wait for the > device to be unused. The WARN_ON/return here breaks all future use of > the device. I assume @attached has something to do with the page table > interface with KVM, but it all looks racy anyway. > > Also, whatever purpose vgpu->released served looks unnecessary now. > Thanks, > Zhi is looking at it.
