drm/xe: Disallow pinning dma-bufs in VRAM

For now only support pinning in TT memory, for two reasons:
1) Avoid pinning in a placement not accessible to some importers.
2) Pinning in VRAM requires PIN accounting which is a to-do.

v2:
- Adjust the dma-buf kunit test accordingly.

Suggested-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230920095001.5539-1-thomas.hellstrom@linux.intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/xe/tests/xe_dma_buf.c b/drivers/gpu/drm/xe/tests/xe_dma_buf.c
index 1c4d875..18c00bc 100644 (file)
--- a/drivers/gpu/drm/xe/tests/xe_dma_buf.c
+++ b/drivers/gpu/drm/xe/tests/xe_dma_buf.c
@@ -149,11 +149,19 @@ static void xe_test_dmabuf_import_same_driver(struct xe_device *xe)
                        /* Is everything where we expect it to be? */
                        xe_bo_lock(import_bo, false);
                        err = xe_bo_validate(import_bo, NULL, false);
-                       if (err && err != -EINTR && err != -ERESTARTSYS)
-                               KUNIT_FAIL(test,
-                                          "xe_bo_validate() failed with err=%d\n", err);
 
-                       check_residency(test, bo, import_bo, dmabuf);
+                       /* Pinning in VRAM is not allowed. */
+                       if (!is_dynamic(params) &&
+                           params->force_different_devices &&
+                           !(params->mem_mask & XE_BO_CREATE_SYSTEM_BIT))
+                               KUNIT_EXPECT_EQ(test, err, -EINVAL);
+                       /* Otherwise only expect interrupts or success. */
+                       else if (err && err != -EINTR && err != -ERESTARTSYS)
+                               KUNIT_EXPECT_TRUE(test, !err || err == -EINTR ||
+                                                 err == -ERESTARTSYS);
+
+                       if (!err)
+                               check_residency(test, bo, import_bo, dmabuf);
                        xe_bo_unlock(import_bo);
                }
                drm_gem_object_put(import);

diff --git a/drivers/gpu/drm/xe/xe_dma_buf.c b/drivers/gpu/drm/xe/xe_dma_buf.c
index 8ce1b58..cfde3be 100644 (file)
--- a/drivers/gpu/drm/xe/xe_dma_buf.c
+++ b/drivers/gpu/drm/xe/xe_dma_buf.c
@@ -49,13 +49,30 @@ static int xe_dma_buf_pin(struct dma_buf_attachment *attach)
 {
        struct drm_gem_object *obj = attach->dmabuf->priv;
        struct xe_bo *bo = gem_to_xe_bo(obj);
+       struct xe_device *xe = xe_bo_device(bo);
+       int ret;
 
        /*
-        * Migrate to TT first to increase the chance of non-p2p clients
-        * can attach.
+        * For now only support pinning in TT memory, for two reasons:
+        * 1) Avoid pinning in a placement not accessible to some importers.
+        * 2) Pinning in VRAM requires PIN accounting which is a to-do.
         */
-       (void)xe_bo_migrate(bo, XE_PL_TT);
-       xe_bo_pin_external(bo);
+       if (xe_bo_is_pinned(bo) && bo->ttm.resource->placement != XE_PL_TT) {
+               drm_dbg(&xe->drm, "Can't migrate pinned bo for dma-buf pin.\n");
+               return -EINVAL;
+       }
+
+       ret = xe_bo_migrate(bo, XE_PL_TT);
+       if (ret) {
+               if (ret != -EINTR && ret != -ERESTARTSYS)
+                       drm_dbg(&xe->drm,
+                               "Failed migrating dma-buf to TT memory: %pe\n",
+                               ERR_PTR(ret));
+               return ret;
+       }
+
+       ret = xe_bo_pin_external(bo);
+       xe_assert(xe, !ret);
 
        return 0;
 }