drm/radeon: add userptr flag to limit it to anonymous memory v2

Avoid problems with writeback by limiting userptr to anonymous memory.

v2: add commit and code comments

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/radeon/radeon_gem.c b/drivers/gpu/drm/radeon/radeon_gem.c
index 993ab22..032736b 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_gem.c
+++ b/drivers/gpu/drm/radeon/radeon_gem.c
@@ -290,7 +290,8 @@ int radeon_gem_userptr_ioctl(struct drm_device *dev, void *data,
                return -EACCES;
 
        /* reject unknown flag values */
-       if (args->flags & ~RADEON_GEM_USERPTR_READONLY)
+       if (args->flags & ~(RADEON_GEM_USERPTR_READONLY |
+           RADEON_GEM_USERPTR_ANONONLY))
                return -EINVAL;
 
        /* readonly pages not tested on older hardware */

diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index b20933f..12e37b1 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -538,6 +538,16 @@ static int radeon_ttm_tt_pin_userptr(struct ttm_tt *ttm)
        if (current->mm != gtt->usermm)
                return -EPERM;
 
+       if (gtt->userflags & RADEON_GEM_USERPTR_ANONONLY) {
+               /* check that we only pin down anonymous memory
+                  to prevent problems with writeback */
+               unsigned long end = gtt->userptr + ttm->num_pages * PAGE_SIZE;
+               struct vm_area_struct *vma;
+               vma = find_vma(gtt->usermm, gtt->userptr);
+               if (!vma || vma->vm_file || vma->vm_end < end)
+                       return -EPERM;
+       }
+
        do {
                unsigned num_pages = ttm->num_pages - pinned;
                uint64_t userptr = gtt->userptr + pinned * PAGE_SIZE;

diff --git a/include/uapi/drm/radeon_drm.h b/include/uapi/drm/radeon_drm.h
index 3a9f209..9720e1a 100644 (file)
--- a/include/uapi/drm/radeon_drm.h
+++ b/include/uapi/drm/radeon_drm.h
@@ -816,6 +816,7 @@ struct drm_radeon_gem_create {
  * perform any operation.
  */
 #define RADEON_GEM_USERPTR_READONLY    (1 << 0)
+#define RADEON_GEM_USERPTR_ANONONLY    (1 << 1)
 
 struct drm_radeon_gem_userptr {
        uint64_t                addr;