On Tue, Apr 04, 2023 at 04:45:12PM -0600, Alex Williamson wrote: > On Sat, 1 Apr 2023 08:18:24 -0700 > Yi Liu <yi.l.liu@xxxxxxxxx> wrote: > > > From: Nicolin Chen <nicolinc@xxxxxxxxxx> > > > > Previously, the detach routine is only done by the destroy(). And it was > > called by vfio_iommufd_emulated_unbind() when the device runs close(), so > > all the mappings in iopt were cleaned in that setup, when the call trace > > reaches this detach() routine. > > > > Now, there's a need of a detach uAPI, meaning that it does not only need > > a new iommufd_access_detach() API, but also requires access->ops->unmap() > > call as a cleanup. So add one. > > > > However, leaving that unprotected can introduce some potential of a race > > condition during the pin_/unpin_pages() call, where access->ioas->iopt is > > getting referenced. So, add an ioas_lock to protect the context of iopt > > referencings. > > > > Also, to allow the iommufd_access_unpin_pages() callback to happen via > > this unmap() call, add an ioas_unpin pointer, so the unpin routine won't > > be affected by the "access->ioas = NULL" trick. > > > > Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx> > > Tested-by: Terrence Xu <terrence.xu@xxxxxxxxx> > > Tested-by: Yanting Jiang <yanting.jiang@xxxxxxxxx> > > Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx> > > Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx> > > --- > > drivers/iommu/iommufd/device.c | 76 +++++++++++++++++++++++-- > > drivers/iommu/iommufd/iommufd_private.h | 2 + > > include/linux/iommufd.h | 1 + > > 3 files changed, 74 insertions(+), 5 deletions(-) > > Does this need to go in via iommufd first? There seems to be quite a > bit of churn in iommufd/device.c vs the vfio_mdev_ops branch (ie. it > doesn't apply). Thanks, I think it is best to stay with this series, Yi has to rebase it Jason
