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; + } + } + +} + 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; }; -- 2.7.4
