drm/xe: Limit sg segment size to PAGE_SIZE on Xen PV

Fix display corruption on Xen PV dom0, where DMA buffers are not
guaranteed machine-contiguous, in which case bounce buffering kicks
in, breaking xe's memory coherency assumptions.

Apply the same workaround i915 carries in i915_sg_segment_size() since
commit 78a07fe777 ("drm/i915: stop abusing swiotlb_max_segment").

Fixes: dd08ebf6c3 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/work_items/8382
Link: https://lore.kernel.org/xen-devel/aYtznP_tT6xNPwf-@mail-itl/
Link: https://lore.kernel.org/all/20221020110308.1582518-1-hch@lst.de/ # i915 counterpart
Cc: Christoph Hellwig <hch@lst.de>
Cc: Robert Beckett <bob.beckett@collabora.com>
Cc: stable@vger.kernel.org # v6.8+
Signed-off-by: Szymon Acedański <accek@invisiblethingslab.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patch.msgid.link/20260916173030.3223833-1-accek@invisiblethingslab.com
(cherry picked from commit 77f704158f)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
This commit is contained in:
Szymon Acedański 2026-09-16 19:30:30 +02:00 • committed by Rodrigo Vivi
commit 141008dec7
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