drm/virtio: implement context init: track valid capabilities in a mask

The valid capability IDs are between 1 to 63, and defined in the
virtio gpu spec.  This is used for error checking the subsequent
patches.  We're currently only using 2 capability IDs, so this
should be plenty for the immediate future.

Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org>
Acked-by: Lingfeng Yang <lfy@google.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20210921232024.817-4-gurchetansingh@chromium.org
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 0c48109..3023e16 100644 (file)
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -55,6 +55,8 @@
 #define STATE_OK 1
 #define STATE_ERR 2
 
+#define MAX_CAPSET_ID 63
+
 struct virtio_gpu_object_params {
        unsigned long size;
        bool dumb;
@@ -245,6 +247,7 @@ struct virtio_gpu_device {
 
        struct virtio_gpu_drv_capset *capsets;
        uint32_t num_capsets;
+       uint64_t capset_id_mask;
        struct list_head cap_cache;
 
        /* protects uuid state when exporting */

diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index f337905..58a6512 100644 (file)
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -65,6 +65,7 @@ static void virtio_gpu_get_capsets(struct virtio_gpu_device *vgdev,
                                   int num_capsets)
 {
        int i, ret;
+       bool invalid_capset_id = false;
 
        vgdev->capsets = kcalloc(num_capsets,
                                 sizeof(struct virtio_gpu_drv_capset),
@@ -78,19 +79,34 @@ static void virtio_gpu_get_capsets(struct virtio_gpu_device *vgdev,
                virtio_gpu_notify(vgdev);
                ret = wait_event_timeout(vgdev->resp_wq,
                                         vgdev->capsets[i].id > 0, 5 * HZ);
-               if (ret == 0) {
+               /*
+                * Capability ids are defined in the virtio-gpu spec and are
+                * between 1 to 63, inclusive.
+                */
+               if (!vgdev->capsets[i].id ||
+                   vgdev->capsets[i].id > MAX_CAPSET_ID)
+                       invalid_capset_id = true;
+
+               if (ret == 0)
                        DRM_ERROR("timed out waiting for cap set %d\n", i);
+               else if (invalid_capset_id)
+                       DRM_ERROR("invalid capset id %u", vgdev->capsets[i].id);
+
+               if (ret == 0 || invalid_capset_id) {
                        spin_lock(&vgdev->display_info_lock);
                        kfree(vgdev->capsets);
                        vgdev->capsets = NULL;
                        spin_unlock(&vgdev->display_info_lock);
                        return;
                }
+
+               vgdev->capset_id_mask |= 1 << vgdev->capsets[i].id;
                DRM_INFO("cap set %d: id %d, max-version %d, max-size %d\n",
                         i, vgdev->capsets[i].id,
                         vgdev->capsets[i].max_version,
                         vgdev->capsets[i].max_size);
        }
+
        vgdev->num_capsets = num_capsets;
 }