The kernel-doc comments for vmapping_counter and vmap_ptr in struct
dma_buf reference "@lock" as the protecting lock, but struct dma_buf
no longer has a "lock" member. The mutex was removed in favor of using
the dma_resv lock exclusively. The implementation correctly uses
dma_resv_assert_held(dmabuf->resv) in dma_buf_vmap() and
dma_buf_vunmap(), so update the documentation to reference @resv
instead.
Signed-off-by: gaoxiang17 <gaoxiang17@xiaomi.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20260415054101.535520-1-gxxa03070307@gmail.com
Some exporters need a flow to synchronously revoke access to the DMA-buf
by importers. Once revoke is completed the importer is not permitted to
touch the memory otherwise they may get IOMMU faults, AERs, or worse.
DMA-buf today defines a revoke flow, for both pinned and dynamic
importers, which is broadly:
dma_resv_lock(dmabuf->resv, NULL);
// Prevent new mappings from being established
priv->revoked = true;
// Tell all importers to eventually unmap
dma_buf_invalidate_mappings(dmabuf);
// Wait for any inprogress fences on the old mapping
dma_resv_wait_timeout(dmabuf->resv,
DMA_RESV_USAGE_BOOKKEEP, false,
MAX_SCHEDULE_TIMEOUT);
dma_resv_unlock(dmabuf->resv, NULL);
// Wait for all importers to complete unmap
wait_for_completion(&priv->unmapped_comp);
This works well, and an importer that continues to access the DMA-buf
after unmapping it is very buggy.
However, the final wait for unmap is effectively unbounded. Several
importers do not support invalidate_mappings() at all and won't unmap
until userspace triggers it.
This unbounded wait is not suitable for exporters like VFIO and RDMA tha
need to issue revoke as part of their normal operations.
Add dma_buf_attach_revocable() to allow exporters to determine the
difference between importers that can complete the above in bounded time,
and those that can't. It can be called inside the exporter's attach op to
reject incompatible importers.
Document these details about how dma_buf_invalidate_mappings() works and
what the required sequence is to achieve a full revocation.
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20260131-dmabuf-revoke-v7-6-463d956bd527@nvidia.com
Pull VFIO updates from Alex Williamson:
"A small cycle with the bulk in selftests and reintroducing poison
handling in the nvgrace-gpu driver. The rest are fixes, cleanups, and
some dmabuf structure consolidation.
- Update outdated mdev comment referencing the renamed
mdev_type_add() function (Julia Lawall)
- Introduce selftest support for IOMMU mapping of PCI MMIO BARs (Alex
Mastro)
- Relax selftest assertion relative to differences in huge page
handling between legacy (v1) TYPE1 IOMMU mapping behavior and the
compatibility mode supported by IOMMUFD (David Matlack)
- Reintroduce memory poison handling support for non-struct-page-
backed memory in the nvgrace-gpu variant driver (Ankit Agrawal)
- Replace dma_buf_phys_vec with phys_vec to avoid duplicate structure
and semantics (Leon Romanovsky)
- Add missing upstream bridge locking across PCI function reset,
resolving an assertion failure when secondary bus reset is used to
provide that reset (Anthony Pighin)
- Fixes to hisi_acc vfio-pci variant driver to resolve corner case
issues related to resets, repeated migration, and error injection
scenarios (Longfang Liu, Weili Qian)
- Restrict vfio selftest builds to arm64 and x86_64, resolving
compiler warnings on 32-bit archs (Ted Logan)
- Un-deprecate the fsl-mc vfio bus driver as a new maintainer has
stepped up (Ioana Ciornei)"
* tag 'vfio-v7.0-rc1' of https://github.com/awilliam/linux-vfio:
vfio/fsl-mc: add myself as maintainer
vfio: selftests: only build tests on arm64 and x86_64
hisi_acc_vfio_pci: fix the queue parameter anomaly issue
hisi_acc_vfio_pci: resolve duplicate migration states
hisi_acc_vfio_pci: update status after RAS error
hisi_acc_vfio_pci: fix VF reset timeout issue
vfio/pci: Lock upstream bridge for vfio_pci_core_disable()
types: reuse common phys_vec type instead of DMABUF open‑coded variant
vfio/nvgrace-gpu: register device memory for poison handling
mm: add stubs for PFNMAP memory failure registration functions
vfio: selftests: Drop IOMMU mapping size assertions for VFIO_TYPE1_IOMMU
vfio: selftests: Add vfio_dma_mapping_mmio_test
vfio: selftests: Align BAR mmaps for efficient IOMMU mapping
vfio: selftests: Centralize IOMMU mode name definitions
vfio/mdev: update outdated comment
Add dma_buf_phys_vec_to_sgt() and dma_buf_free_sgt() helpers to convert
an array of MMIO physical address ranges into scatter-gather tables with
proper DMA mapping.
These common functions are a starting point and support any PCI
drivers creating mappings from their BAR's MMIO addresses. VFIO is one
case, as shortly will be RDMA. We can review existing DRM drivers to
refactor them separately. We hope this will evolve into routines to
help common DRM that include mixed CPU and MMIO mappings.
Compared to the dma_map_resource() abuse this implementation handles
the complicated PCI P2P scenarios properly, especially when an IOMMU
is enabled:
- Direct bus address mapping without IOVA allocation for
PCI_P2PDMA_MAP_BUS_ADDR, using pci_p2pdma_bus_addr_map(). This
happens if the IOMMU is enabled but the PCIe switch ACS flags allow
transactions to avoid the host bridge.
Further, this handles the slightly obscure, case of MMIO with a
phys_addr_t that is different from the physical BAR programming
(bus offset). The phys_addr_t is converted to a dma_addr_t and
accommodates this effect. This enables certain real systems to
work, especially on ARM platforms.
- Mapping through host bridge with IOVA allocation and DMA_ATTR_MMIO
attribute for MMIO memory regions (PCI_P2PDMA_MAP_THRU_HOST_BRIDGE).
This happens when the IOMMU is enabled and the ACS flags are forcing
all traffic to the IOMMU - ie for virtualization systems.
- Cases where P2P is not supported through the host bridge/CPU. The
P2P subsystem is the proper place to detect this and block it.
Helper functions fill_sg_entry() and calc_sg_nents() handle the
scatter-gather table construction, splitting large regions into
UINT_MAX-sized chunks to fit within sg->length field limits.
Since the physical address based DMA API forbids use of the CPU list
of the scatterlist this will produce a mangled scatterlist that has
a fully zero-length and NULL'd CPU list. The list is 0 length,
all the struct page pointers are NULL and zero sized. This is stronger
and more robust than the existing mangle_sg_table() technique. It is
a future project to migrate DMABUF as a subsystem away from using
scatterlist for this data structure.
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Alex Mastro <amastro@fb.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Ankit Agrawal <ankita@nvidia.com>
Link: https://lore.kernel.org/r/20251120-dmabuf-vfio-v9-6-d7f71607f371@nvidia.com
Signed-off-by: Alex Williamson <alex@shazbot.org>
Pull bpf updates from Alexei Starovoitov:
- Fix and improve BTF deduplication of identical BTF types (Alan
Maguire and Andrii Nakryiko)
- Support up to 12 arguments in BPF trampoline on arm64 (Xu Kuohai and
Alexis Lothoré)
- Support load-acquire and store-release instructions in BPF JIT on
riscv64 (Andrea Parri)
- Fix uninitialized values in BPF_{CORE,PROBE}_READ macros (Anton
Protopopov)
- Streamline allowed helpers across program types (Feng Yang)
- Support atomic update for hashtab of BPF maps (Hou Tao)
- Implement json output for BPF helpers (Ihor Solodrai)
- Several s390 JIT fixes (Ilya Leoshkevich)
- Various sockmap fixes (Jiayuan Chen)
- Support mmap of vmlinux BTF data (Lorenz Bauer)
- Support BPF rbtree traversal and list peeking (Martin KaFai Lau)
- Tests for sockmap/sockhash redirection (Michal Luczaj)
- Introduce kfuncs for memory reads into dynptrs (Mykyta Yatsenko)
- Add support for dma-buf iterators in BPF (T.J. Mercier)
- The verifier support for __bpf_trap() (Yonghong Song)
* tag 'bpf-next-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (135 commits)
bpf, arm64: Remove unused-but-set function and variable.
selftests/bpf: Add tests with stack ptr register in conditional jmp
bpf: Do not include stack ptr register in precision backtracking bookkeeping
selftests/bpf: enable many-args tests for arm64
bpf, arm64: Support up to 12 function arguments
bpf: Check rcu_read_lock_trace_held() in bpf_map_lookup_percpu_elem()
bpf: Avoid __bpf_prog_ret0_warn when jit fails
bpftool: Add support for custom BTF path in prog load/loadall
selftests/bpf: Add unit tests with __bpf_trap() kfunc
bpf: Warn with __bpf_trap() kfunc maybe due to uninitialized variable
bpf: Remove special_kfunc_set from verifier
selftests/bpf: Add test for open coded dmabuf_iter
selftests/bpf: Add test for dmabuf_iter
bpf: Add open coded dmabuf iterator
bpf: Add dmabuf iterator
dma-buf: Rename debugfs symbols
bpf: Fix error return value in bpf_copy_from_user_dynptr
libbpf: Use mmap to parse vmlinux BTF from sysfs
selftests: bpf: Add a test for mmapable vmlinux BTF
btf: Allow mmap of vmlinux btf
...
Instead of distingting between shared and exclusive fences specify
the fence usage while adding fences.
Rework all drivers to use this interface instead and deprecate the old one.
v2: some kerneldoc comments suggested by Daniel
v3: fix a missing case in radeon
v4: rebase on nouveau changes, fix lockdep and temporary disable warning
v5: more documentation updates
v6: separate internal dma_resv changes from this patch, avoids to
disable warning temporary, rebase on upstream changes
v7: fix missed case in lima driver, minimize changes to i915_gem_busy_ioctl
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-3-christian.koenig@amd.com
This change adds the dma_resv_usage enum and allows us to specify why a
dma_resv object is queried for its containing fences.
Additional to that a dma_resv_usage_rw() helper function is added to aid
retrieving the fences for a read or write userspace submission.
This is then deployed to the different query functions of the dma_resv
object and all of their users. When the write paratermer was previously
true we now use DMA_RESV_USAGE_WRITE and DMA_RESV_USAGE_READ otherwise.
v2: add KERNEL/OTHER in separate patch
v3: some kerneldoc suggestions by Daniel
v4: some more kerneldoc suggestions by Daniel, fix missing cases lost in
the rebase pointed out by Bas.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-2-christian.koenig@amd.com
So far we had the approach of using a directed acyclic
graph with the dma_resv obj.
This turned out to have many downsides, especially it means
that every single driver and user of this interface needs
to be aware of this restriction when adding fences. If the
rules for the DAG are not followed then we end up with
potential hard to debug memory corruption, information
leaks or even elephant big security holes because we allow
userspace to access freed up memory.
Since we already took a step back from that by always
looking at all fences we now go a step further and stop
dropping the shared fences when a new exclusive one is
added.
v2: Drop some now superflous documentation
v3: Add some more documentation for the new handling.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220321135856.1331-11-christian.koenig@amd.com
