Re: [PATCH v4 0/5] accel/amdxdna: SYNC_BO correctness fixes

Patch 1 needs a prerequisite. It makes amdxdna_gem_vmap() answer NULL on 
an iomem exporter, and the eight amdxdna_cmd_get_payload() callers in 
aie2_message.c check neither the pointer nor the length it leaves 
unwritten there. A command BO can be an import, so patch 1 alone turns a 
silent __iomem write into a NULL deref with an uninitialised length.
https://lore.kernel.org/all/[email protected]/

fixes the callers. Happy to respin on top if you prefer them together.

Taimuraz

On 8/18/26 02:07, Taimuraz Kaitmazov wrote:
> Five fixes in and around amdxdna_drm_sync_bo_ioctl().
>
> Patch 1 refuses an I/O memory mapping the driver would otherwise store as
> if it were an ordinary kernel address. Patch 2 checks the device-BO range
> for overflow. Patch 4 refuses a flush of an imported BO, which is why
> patch 3 comes first: the ioctl answers a rejected flush with drm_WARN(),
> so without it an ordinary sync on an imported BO splats. Patch 5 stops
> the ioctl reporting failure for a flush that succeeded.
>
> v3's zero-length patch has left this series. On hardware it turns out to
> be a page fault in drm_clflush_virt_range() rather than the tidy-up its
> commit message described, so it is a -fixes patch now, sent separately as
> "accel/amdxdna: return early from a zero-length flush" with Fixes: and
> Cc: stable. Patch 4 here needs its hunk, so this series wants that one
> first.
>
> Changes in v4:
>    - patch 1: the is_iomem check moved from the .vmap callback into
>      amdxdna_gem_vmap(), per Lizhi, and it logs at debug level rather than
>      error, since an unprivileged caller can repeat it.
>    - new patch 3: an unprivileged SYNC_BO with an out-of-range offset
>      already reaches that drm_WARN() today. Sashiko's review of v3 3/3
>      flagged the same thing.
>    - new patch 4: refuses the flush for every imported BO, as asked.
>    - new patch 5: the debug-BO sync I mentioned on the v2 thread. Only a BO
>      attached with ATTACH_DEBUG_BO has an assigned hwctx, so every other
>      FROM_DEVICE sync ends in -EINVAL with its flush already done. The
>      -EINVAL reproduces on a Strix Point NPU.
>
> On patch 4, one consequence worth deciding before it lands. A heap BO is
> created through amdxdna_drm_create_share_bo(), so a device running on
> carveout memory reaches its heap through a cbuf, is_import_bo() is true of
> it, and SYNC_BO on every AMDXDNA_BO_DEV now answers -EOPNOTSUPP. Today
> that path flushes nothing anyway -- amdxdna_cbuf_map() fills in only the
> DMA address and length, so drm_clflush_sg() walks zero pages -- so the
> change is silent no-op to hard error, and XRT's dbg_buffer::sync() reaches
> it without Debug.force_driver_sync. If you would rather keep our own
> exporters working, I have the variant keyed on the exporter's ops, which
> confines the refusal to foreign buffers. Say which you prefer.
>
> v3: https://lore.kernel.org/all/[email protected]/
>
> Built on drm-misc-next, each commit on its own: x86_64 with
> DRM_ACCEL_AMDXDNA=m, clang 22.1.8, no warnings. Patch 5's reproducer was
> run against 7.1.8's in-tree driver, where that call is unchanged.
>
> Taimuraz Kaitmazov (5):
>    accel/amdxdna: refuse an I/O memory mapping of an imported BO
>    accel/amdxdna: check the sync range for overflow on a device BO
>    accel/amdxdna: do not warn when a sync request is rejected
>    accel/amdxdna: refuse to flush an imported BO
>    accel/amdxdna: do not fail a sync for a BO with no debug context
>
>   drivers/accel/amdxdna/amdxdna_ctx.c |  3 ++-
>   drivers/accel/amdxdna/amdxdna_gem.c | 27 +++++++++++++++++++--------
>   2 files changed, 21 insertions(+), 9 deletions(-)
>