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.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
arch/powerpc/kvm/book3s_hv_uvmem.c | 4 ++++
drivers/gpu/drm/nouveau/nouveau_dmem.c | 3 +++
include/linux/memremap.h | 4 ++++
include/linux/migrate.h | 2 ++
mm/migrate.c | 3 +++
5 files changed, 16 insertions(+)
diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c
index 79b1202b1c62..29ed52892d31 100644
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
@@ -386,6 +386,7 @@ kvmppc_svm_page_in(struct vm_area_struct *vma, unsigned long start,
mig.end = end;
mig.src = &src_pfn;
mig.dst = &dst_pfn;
+ mig.dev_private_owner = &kvmppc_uvmem_pgmap;
/*
* We come here with mmap_sem write lock held just for
@@ -563,6 +564,7 @@ kvmppc_svm_page_out(struct vm_area_struct *vma, unsigned long start,
mig.end = end;
mig.src = &src_pfn;
mig.dst = &dst_pfn;
+ mig.dev_private_owner = &kvmppc_uvmem_pgmap;
mutex_lock(&kvm->arch.uvmem_lock);
/* The requested page is already paged-out, nothing to do */
@@ -779,6 +781,8 @@ int kvmppc_uvmem_init(void)
kvmppc_uvmem_pgmap.type = MEMORY_DEVICE_PRIVATE;
kvmppc_uvmem_pgmap.res = *res;
kvmppc_uvmem_pgmap.ops = &kvmppc_uvmem_ops;
+ /* just one global instance: */
+ kvmppc_uvmem_pgmap.owner = &kvmppc_uvmem_pgmap;
addr = memremap_pages(&kvmppc_uvmem_pgmap, NUMA_NO_NODE);
if (IS_ERR(addr)) {
ret = PTR_ERR(addr);
diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.c b/drivers/gpu/drm/nouveau/nouveau_dmem.c
index 0ad5d87b5a8e..7605c4c48985 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dmem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c
@@ -176,6 +176,7 @@ static vm_fault_t nouveau_dmem_migrate_to_ram(struct vm_fault *vmf)
.end = vmf->address + PAGE_SIZE,
.src = &src,
.dst = &dst,
+ .dev_private_owner = drm->dev,
};
/*
@@ -526,6 +527,7 @@ nouveau_dmem_init(struct nouveau_drm *drm)
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;
@@ -631,6 +633,7 @@ nouveau_dmem_migrate_vma(struct nouveau_drm *drm,
struct migrate_vma args = {
.vma = vma,
.start = start,
+ .dev_private_owner = drm->dev,
};
unsigned long c, i;
int ret = -ENOMEM;
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 6fefb09af7c3..60d97e8fd3c0 100644
--- 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;
@@ -113,6 +116,7 @@ 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)
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 72120061b7d4..4bbd8d732e53 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -196,6 +196,8 @@ struct migrate_vma {
unsigned long npages;
unsigned long start;
unsigned long end;
+
+ void *dev_private_owner;
};
int migrate_vma_setup(struct migrate_vma *args);
diff --git a/mm/migrate.c b/mm/migrate.c
index b1092876e537..201e8fa627e0 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2267,6 +2267,9 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
goto next;
page = device_private_entry_to_page(entry);
+ if (page->pgmap->owner != migrate->dev_private_owner)
+ goto next;
+
mpfn = migrate_pfn(page_to_pfn(page)) |
MIGRATE_PFN_MIGRATE;
if (is_write_device_private_entry(entry))
--
2.24.1
