On Wed, 29 Jan 2020 04:11:47 -0800 "Liu, Yi L" <yi.l.liu@xxxxxxxxx> wrote: > From: Liu Yi L <yi.l.liu@xxxxxxxxx> > > When userspace application is down, kernel should reclaim the PASIDs > allocated for this application to avoid PASID leak. This patch adds > a PASID list in vfio_mm structure to track the allocated PASIDs. The > PASID reclaim will be triggered when last vfio container is released. > > Previous discussions: > https://patchwork.kernel.org/patch/11209429/ > > Cc: Kevin Tian <kevin.tian@xxxxxxxxx> > CC: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> > Cc: Alex Williamson <alex.williamson@xxxxxxxxxx> > Cc: Eric Auger <eric.auger@xxxxxxxxxx> > Cc: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx> > Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx> > --- > drivers/vfio/vfio.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++--- > include/linux/vfio.h | 6 ++++++ > 2 files changed, 64 insertions(+), 3 deletions(-) > > diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c > index c43c757..425d60a 100644 > --- a/drivers/vfio/vfio.c > +++ b/drivers/vfio/vfio.c > @@ -2148,15 +2148,31 @@ static struct vfio_mm *vfio_create_mm(struct mm_struct *mm) > vmm->pasid_quota = VFIO_DEFAULT_PASID_QUOTA; > vmm->pasid_count = 0; > mutex_init(&vmm->pasid_lock); > + INIT_LIST_HEAD(&vmm->pasid_list); > > list_add(&vmm->vfio_next, &vfio.vfio_mm_list); > > return vmm; > } > > +static void vfio_mm_reclaim_pasid(struct vfio_mm *vmm) > +{ > + struct pasid_node *pnode, *tmp; > + > + mutex_lock(&vmm->pasid_lock); > + list_for_each_entry_safe(pnode, tmp, &vmm->pasid_list, next) { > + pr_info("%s, reclaim pasid: %u\n", __func__, pnode->pasid); > + list_del(&pnode->next); > + ioasid_free(pnode->pasid); > + kfree(pnode); > + } > + mutex_unlock(&vmm->pasid_lock); > +} > + > static void vfio_mm_unlock_and_free(struct vfio_mm *vmm) > { > mutex_unlock(&vfio.vfio_mm_lock); > + vfio_mm_reclaim_pasid(vmm); > kfree(vmm); > } > > @@ -2204,6 +2220,39 @@ struct vfio_mm *vfio_mm_get_from_task(struct task_struct *task) > } > EXPORT_SYMBOL_GPL(vfio_mm_get_from_task); > > +/** > + * Caller should hold vmm->pasid_lock > + */ > +static int vfio_mm_insert_pasid_node(struct vfio_mm *vmm, u32 pasid) > +{ > + struct pasid_node *pnode; > + > + pnode = kzalloc(sizeof(*pnode), GFP_KERNEL); > + if (!pnode) > + return -ENOMEM; > + pnode->pasid = pasid; > + list_add(&pnode->next, &vmm->pasid_list); > + > + return 0; > +} > + > +/** > + * Caller should hold vmm->pasid_lock > + */ > +static void vfio_mm_remove_pasid_node(struct vfio_mm *vmm, u32 pasid) > +{ > + struct pasid_node *pnode, *tmp; > + > + list_for_each_entry_safe(pnode, tmp, &vmm->pasid_list, next) { > + if (pnode->pasid == pasid) { > + list_del(&pnode->next); > + kfree(pnode); > + break; > + } The _safe() list walk variant is only needed when we continue to walk the list after removing an entry. Thanks, Alex > + } > + > +} > + > int vfio_mm_pasid_alloc(struct vfio_mm *vmm, int min, int max) > { > ioasid_t pasid; > @@ -2221,9 +2270,15 @@ int vfio_mm_pasid_alloc(struct vfio_mm *vmm, int min, int max) > ret = -ENOSPC; > goto out_unlock; > } > - vmm->pasid_count++; > > - ret = pasid; > + if (vfio_mm_insert_pasid_node(vmm, pasid)) { > + ret = -ENOSPC; > + ioasid_free(pasid); > + } else { > + ret = pasid; > + vmm->pasid_count++; > + } > + > out_unlock: > mutex_unlock(&vmm->pasid_lock); > return ret; > @@ -2243,7 +2298,7 @@ int vfio_mm_pasid_free(struct vfio_mm *vmm, ioasid_t pasid) > goto out_unlock; > } > ioasid_free(pasid); > - > + vfio_mm_remove_pasid_node(vmm, pasid); > vmm->pasid_count--; > out_unlock: > mutex_unlock(&vmm->pasid_lock); > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > index b6c9c8c..a2ea7e0 100644 > --- a/include/linux/vfio.h > +++ b/include/linux/vfio.h > @@ -89,12 +89,18 @@ extern int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops *ops); > extern void vfio_unregister_iommu_driver( > const struct vfio_iommu_driver_ops *ops); > > +struct pasid_node { > + u32 pasid; > + struct list_head next; > +}; > + > #define VFIO_DEFAULT_PASID_QUOTA 1000 > struct vfio_mm { > struct kref kref; > struct mutex pasid_lock; > int pasid_quota; > int pasid_count; > + struct list_head pasid_list; > struct mm_struct *mm; > struct list_head vfio_next; > };
