From 19ad6d9cce3853d89402af7d180c78ebaf453334 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Mon, 16 Mar 2020 20:32:13 +0100
Subject: memremap: add an owner field to struct dev_pagemap
Git-commit: f894ddd5ff01d3bb48faf4dc533536bf5269c17a
Patch-mainline: v5.7-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322
Add a new opaque owner field to struct dev_pagemap, which will allow the
hmm and migrate_vma code to identify who owns ZONE_DEVICE memory, and
refuse to work on mappings not owned by the calling entity.
Link: https://lore.kernel.org/r/20200316193216.920734-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Tested-by: Bharata B Rao <bharata@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/nouveau/nouveau_dmem.c | 1 +
include/linux/memremap.h | 4 ++++
mm/memremap.c | 4 ++++
3 files changed, 9 insertions(+)
--- a/drivers/gpu/drm/nouveau/nouveau_dmem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c
@@ -526,6 +526,7 @@ nouveau_dmem_init(struct nouveau_drm *dr
drm->dmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
drm->dmem->pagemap.res = *res;
drm->dmem->pagemap.ops = &nouveau_dmem_pagemap_ops;
+ drm->dmem->pagemap.owner = drm->dev;
if (IS_ERR(devm_memremap_pages(device, &drm->dmem->pagemap)))
goto out_free;
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -103,6 +103,9 @@ struct dev_pagemap_ops {
* @type: memory type: see MEMORY_* in memory_hotplug.h
* @flags: PGMAP_* flags to specify defailed behavior
* @ops: method table
+ * @owner: an opaque pointer identifying the entity that manages this
+ * instance. Used by various helpers to make sure that no
+ * foreign ZONE_DEVICE memory is accessed.
*/
struct dev_pagemap {
struct vmem_altmap altmap;
@@ -114,6 +117,7 @@ struct dev_pagemap {
enum memory_type type;
unsigned int flags;
const struct dev_pagemap_ops *ops;
+ void *owner;
};
static inline struct vmem_altmap *pgmap_altmap(struct dev_pagemap *pgmap)
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -186,6 +186,10 @@ void *devm_memremap_pages(struct device
WARN(1, "Missing migrate_to_ram method\n");
return ERR_PTR(-EINVAL);
}
+ if (!pgmap->owner) {
+ WARN(1, "Missing owner\n");
+ return ERR_PTR(-EINVAL);
+ }
break;
case MEMORY_DEVICE_FS_DAX:
if (!IS_ENABLED(CONFIG_ZONE_DEVICE) ||