On Tue, Feb 15, 2022 at 5:15 PM Rob Clark robdclark@gmail.com wrote:

From: Rob Clark robdclark@chromium.org

The UABI was already defined for pointer to 64b value, and all the userspace users of this ioctl that I could find are already using a uint64_t (but zeroing it out to work around kernel only copying 32b). Unfortunately this ioctl doesn't have a length field, so out of paranoia I restricted the change to copy 64b to the single 64b param that can be queried.

Fixes: 78aa20fa4381 ("drm/virtio: implement context init: advertise feature to userspace") Signed-off-by: Rob Clark robdclark@chromium.org

Reviewed-by: Gurchetan Singh gurchetansingh@chromium.org

---

drivers/gpu/drm/virtio/virtgpu_ioctl.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c index 0f2f3f54dbf9..0158d27d5645 100644 --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c @@ -269,7 +269,8 @@ static int virtio_gpu_getparam_ioctl(struct drm_device *dev, void *data, { struct virtio_gpu_device *vgdev = dev->dev_private; struct drm_virtgpu_getparam *param = data;

•   int value;
  

•   int value, ret, sz = sizeof(int);
  

•   uint64_t value64;
  
    switch (param->param) {
    case VIRTGPU_PARAM_3D_FEATURES:
  

@@ -291,13 +292,20 @@ static int virtio_gpu_getparam_ioctl(struct drm_device *dev, void *data, value = vgdev->has_context_init ? 1 : 0; break; case VIRTGPU_PARAM_SUPPORTED_CAPSET_IDs:

•           value = vgdev->capset_id_mask;
  

•           value64 = vgdev->capset_id_mask;
  

•           sz = sizeof(value64);
            break;
    default:
            return -EINVAL;
    }
  

•   if (copy_to_user(u64_to_user_ptr(param->value), &value,
  

sizeof(int)))

•           return -EFAULT;
  

•   if (sz == sizeof(int)) {
  

•           if (copy_to_user(u64_to_user_ptr(param->value), &value,
  

sz))

•                   return -EFAULT;
  

•   } else {
  

•           if (copy_to_user(u64_to_user_ptr(param->value), &value64,
  

sz))

•                   return -EFAULT;
  

•   }
  
    return 0;
  

}

2.34.1