Hi, Leon,
On Sun, 2026-01-18 at 14:08 +0200, Leon Romanovsky wrote:
Changelog: v2: * Changed series to document the revoke semantics instead of implementing it. v1: https://patch.msgid.link/20260111-dmabuf-revoke-v1-0-fb4bcc8c259b@nvidia.com
This series documents a dma-buf “revoke” mechanism: to allow a dma- buf exporter to explicitly invalidate (“kill”) a shared buffer after it has been distributed to importers, so that further CPU and device access is prevented and importers reliably observe failure.
The change in this series is to properly document and use existing core “revoked” state on the dma-buf object and a corresponding exporter- triggered revoke operation. Once a dma-buf is revoked, new access paths are blocked so that attempts to DMA-map, vmap, or mmap the buffer fail in a consistent way.
This sounds like it does not match how many GPU-drivers use the move_notify() callback.
move_notify() would typically invalidate any device maps and any asynchronous part of that invalidation would be complete when the dma- buf's reservation object becomes idle WRT DMA_RESV_USAGE_BOOKKEEP fences.
However, the importer could, after obtaining the resv lock, obtain a new map using dma_buf_map_attachment(), and I'd assume the CPU maps work in the same way, I.E. move_notify() does not *permanently* revoke importer access.
/Thomas
Thanks
Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Cc: linux-kernel@vger.kernel.org Cc: amd-gfx@lists.freedesktop.org Cc: virtualization@lists.linux.dev Cc: intel-xe@lists.freedesktop.org Cc: linux-rdma@vger.kernel.org Cc: iommu@lists.linux.dev Cc: kvm@vger.kernel.org To: Sumit Semwal sumit.semwal@linaro.org To: Christian König christian.koenig@amd.com To: Alex Deucher alexander.deucher@amd.com To: David Airlie airlied@gmail.com To: Simona Vetter simona@ffwll.ch To: Gerd Hoffmann kraxel@redhat.com To: Dmitry Osipenko dmitry.osipenko@collabora.com To: Gurchetan Singh gurchetansingh@chromium.org To: Chia-I Wu olvaffe@gmail.com To: Maarten Lankhorst maarten.lankhorst@linux.intel.com To: Maxime Ripard mripard@kernel.org To: Thomas Zimmermann tzimmermann@suse.de To: Lucas De Marchi lucas.demarchi@intel.com To: Thomas Hellström thomas.hellstrom@linux.intel.com To: Rodrigo Vivi rodrigo.vivi@intel.com To: Jason Gunthorpe jgg@ziepe.ca To: Leon Romanovsky leon@kernel.org To: Kevin Tian kevin.tian@intel.com To: Joerg Roedel joro@8bytes.org To: Will Deacon will@kernel.org To: Robin Murphy robin.murphy@arm.com To: Alex Williamson alex@shazbot.org
Leon Romanovsky (4): dma-buf: Rename .move_notify() callback to a clearer identifier dma-buf: Document revoke semantics iommufd: Require DMABUF revoke semantics vfio: Add pinned interface to perform revoke semantics
drivers/dma-buf/dma-buf.c | 6 +++--- drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 4 ++-- drivers/gpu/drm/virtio/virtgpu_prime.c | 2 +- drivers/gpu/drm/xe/tests/xe_dma_buf.c | 6 +++--- drivers/gpu/drm/xe/xe_dma_buf.c | 2 +- drivers/infiniband/core/umem_dmabuf.c | 4 ++-- drivers/infiniband/hw/mlx5/mr.c | 2 +- drivers/iommu/iommufd/pages.c | 11 +++++++++-- drivers/vfio/pci/vfio_pci_dmabuf.c | 16 ++++++++++++++++ include/linux/dma-buf.h | 25 ++++++++++++++++++++++--- 10 files changed, 60 insertions(+), 18 deletions(-)
base-commit: 9ace4753a5202b02191d54e9fdf7f9e3d02b85eb change-id: 20251221-dmabuf-revoke-b90ef16e4236
Best regards, -- Leon Romanovsky leonro@nvidia.com