[drm-next,0/2] Enhance drm_panic Support for Virtio-GPU

Message

Ryosuke Yasuoka March 5, 2025, 3:25 p.m. UTC

Hi

This patch series proposes enhancement for drm_panic. While virtio-gpu
currently supports drm_panic [1], it is limited to vmapped shmem BOs.
IOW, it does not work in non-VT FB environments, such as GUI desktops.
This limitation arises because shmem BOs require vmap, which cannot be
used in a panic handler since vmap is sleepable and takes locks. To
address this, drm_panic needs an atomic variant of vmap.

The first patch (1/2) introduces atomic_vmap, and the second patch (2/2)
updates the existing virtio drm_panic implementation to use the
atomic_vmap. I've tested these changes in both Gnome and VT
environments, and they work correctly.

Best regards,
Ryosuke

[1] https://patchwork.freedesktop.org/patch/635658/ 

Ryosuke Yasuoka (2):
  vmalloc: Add atomic_vmap
  drm/virtio: Use atomic_vmap to work drm_panic in GUI

 drivers/gpu/drm/drm_gem.c              |  51 ++++++++++++
 drivers/gpu/drm/drm_gem_shmem_helper.c |  51 ++++++++++++
 drivers/gpu/drm/virtio/virtgpu_plane.c |  14 +++-
 include/drm/drm_gem.h                  |   1 +
 include/drm/drm_gem_shmem_helper.h     |   2 +
 include/linux/vmalloc.h                |   2 +
 mm/internal.h                          |   5 ++
 mm/vmalloc.c                           | 105 +++++++++++++++++++++++++
 8 files changed, 228 insertions(+), 3 deletions(-)


base-commit: e21cba704714c301d04c5fd37a693734b623872a