Re: [PATCH v9 5/7] vfio: Define vfio based dma-buf operations

From: Gerd Hoffmann
Date: Mon Jun 19 2017 - 02:38:30 EST


> My suggestion was to use vfio device fd for this ioctl and have
> dmabuf
> mgr fd as member in above query_plane structure, for region type it
> would be set to 0.

Region type should be DRM_PLANE_TYPE_PRIMARY

> Can't mmap that page to get surface information. There is no way to
> synchronize between QEMU reading this mmapped region and vendor
> driver
> writing it. There could be race condition in these two operations.
> Read
> on this page should be trapped and blocking, so that surface in that
> region is only updated when its asked for.

Does it make sense to have a "generation" field in the plane_info
struct (which gets increased each time the struct changes) ?