queue-5.0/drm-virtio-do-not-reuse-resource-ids.patch

   1 From 16065fcdd19ddb9e093192914ac863884f308766 Mon Sep 17 00:00:00 2001
   2 From: Gerd Hoffmann <kraxel@redhat.com>
   3 Date: Fri, 8 Feb 2019 15:04:09 +0100
   4 Subject: drm/virtio: do NOT reuse resource ids
   5
   6 From: Gerd Hoffmann <kraxel@redhat.com>
   7
   8 commit 16065fcdd19ddb9e093192914ac863884f308766 upstream.
   9
  10 Bisected guest kernel changes crashing qemu.  Landed at
  11 "6c1cd97bda drm/virtio: fix resource id handling".  Looked again, and
  12 noticed we where not only leaking *some* ids, but *all* ids.  The old
  13 code never ever called virtio_gpu_resource_id_put().
  14
  15 So, commit 6c1cd97bda effectively makes the linux kernel starting
  16 re-using IDs after releasing them, and apparently virglrenderer can't
  17 deal with that.  Oops.
  18
  19 This patch puts a temporary stopgap into place for the 5.0 release.
  20
  21 Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
  22 Reviewed-by: Dave Airlie <airlied@redhat.com>
  23 Signed-off-by: Dave Airlie <airlied@redhat.com>
  24 Link: https://patchwork.freedesktop.org/patch/msgid/20190208140409.15280-1-kraxel@redhat.com
  25 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  26
  27 ---
  28  drivers/gpu/drm/virtio/virtgpu_object.c |   13 +++++++++++++
  29  1 file changed, 13 insertions(+)
  30
  31 --- a/drivers/gpu/drm/virtio/virtgpu_object.c
  32 +++ b/drivers/gpu/drm/virtio/virtgpu_object.c
  33 @@ -28,10 +28,21 @@
  34  static int virtio_gpu_resource_id_get(struct virtio_gpu_device *vgdev,
  35                                        uint32_t *resid)
  36  {
  37 +#if 0
  38         int handle = ida_alloc(&vgdev->resource_ida, GFP_KERNEL);
  39
  40         if (handle < 0)
  41                 return handle;
  42 +#else
  43 +       static int handle;
  44 +
  45 +       /*
  46 +        * FIXME: dirty hack to avoid re-using IDs, virglrenderer
  47 +        * can't deal with that.  Needs fixing in virglrenderer, also
  48 +        * should figure a better way to handle that in the guest.
  49 +        */
  50 +       handle++;
  51 +#endif
  52
  53         *resid = handle + 1;
  54         return 0;
  55 @@ -39,7 +50,9 @@ static int virtio_gpu_resource_id_get(st
  56
  57  static void virtio_gpu_resource_id_put(struct virtio_gpu_device *vgdev, uint32_t id)
  58  {
  59 +#if 0
  60         ida_free(&vgdev->resource_ida, id - 1);
  61 +#endif
  62  }
  63
  64  static void virtio_gpu_ttm_bo_destroy(struct ttm_buffer_object *tbo)