On Tue, Jul 20 2021, Jason Gunthorpe <jgg@xxxxxxxxxx> wrote: > Currently the driver ops have an open/release pair that is called once > each time a device FD is opened or closed. Add an additional set of > open/close_device() ops which are called when the device FD is opened for > the first time and closed for the last time. > > An analysis shows that all of the drivers require this semantic. Some are > open coding it as part of their reflck implementation, and some are just > buggy and miss it completely. > > To retain the current semantics PCI and FSL depend on, introduce the idea > of a "device set" which is a grouping of vfio_device's that share the same > lock around opening. > > The device set is established by providing a 'set_id' pointer. All > vfio_device's that provide the same pointer will be joined to the same > singleton memory and lock across the whole set. This effectively replaces > the oddly named reflck. > > After conversion the set_id will be sourced from: > - A struct device from a fsl_mc_device (fsl) > - A struct pci_slot (pci) > - A struct pci_bus (pci) > - The struct vfio_device (everything) > > The design ensures that the above pointers are live as long as the > vfio_device is registered, so they form reliable unique keys to group > vfio_devices into sets. > > This implementation uses xarray instead of searching through the driver > core structures, which simplifies the somewhat tricky locking in this > area. > > Following patches convert all the drivers. > > Signed-off-by: Yishai Hadas <yishaih@xxxxxxxxxx> > Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx> > --- > drivers/vfio/mdev/vfio_mdev.c | 22 +++++ > drivers/vfio/vfio.c | 146 +++++++++++++++++++++++++++++----- > include/linux/mdev.h | 2 + > include/linux/vfio.h | 19 +++++ > 4 files changed, 167 insertions(+), 22 deletions(-) Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
