[PATCH v3 0/6] gpu: nova-core: run unload sequence upon unbinding

[Alexandre Courbot]

Currently the GSP is left running and the WPR2 memory region untouched
when the driver is unbound. This is obviously not ideal for at least two
reasons:

- Probing requires setting up the WPR2 region, which cannot be done if
  there is already one in place. Hence the current requirement to reset
  the GPU (using e.g. `echo 1 >/sys/bus/pci/devices/.../reset`) before
  the driver can be probed again after removal.
- The running GSP may still attempt to access shared memory regions
  which the kernel might recycle.

On top of that, there is a nasty bug in the Blackwell VBIOS that
sometimes borks the GPU upon PCI reset, requiring a reboot. So relying
on the PCI reset to unload/reload Nova is really not practical here.

This series does what is needed to leave the GPU in a clean state after
unbind, for all currently supported GPUs. Blackwell support is trivial
and will be added alongside the Blackwell series [1] if this can be
merged first.

The first patch adds a `warn_on_err` utility macro to the kernel crate
as it is useful to warn on failures in the driver unbind path, but I can
remove it if it is not deemed useful.

This series applies cleanly on `master` as of today.

[1] https://lore.kernel.org/all/20260411024953.473149-1-jhubbard@xxxxxxxxxx/

Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
---
Changes in v3:
- Disambiguate doccomment for `warn_on_err`.
- Test the correct bit instead of the whole register value to determine
  that the GSP has stopped.
- Use an enum instead of a boolean to encode the power level when
  shutting down the GSP.
- Add missing newline to `dev_err`.
- Add missing doccomments for new types.
- Use values from bindings instead of magic numbers.
- Remove the redundant `get_gsp_info` function.
- Better document Booter Unloader mailbox sentinel value, and check the
  value of mbox0 upon return.
- Link to v2: https://patch.msgid.link/20260421-nova-unload-v2-0-2fe54963af8b@xxxxxxxxxx

Changes in v2:
- Rebase on top of `master` and remove unneeded/obsolete preparatory patches.
- Tidy up the imports of commands from the `fw` module in the `gsp` module.
- Link to v1: https://patch.msgid.link/20251216-nova-unload-v1-0-6a5d823be19d@xxxxxxxxxx

---
Alexandre Courbot (6):
      rust: add warn_on_err macro
      gpu: nova-core: use warn_on_err macro
      gpu: nova-core: remove unneeded get_gsp_info proxy function
      gpu: nova-core: do not import firmware commands into GSP command module
      gpu: nova-core: send UNLOADING_GUEST_DRIVER GSP command upon unloading
      gpu: nova-core: run Booter Unloader and FWSEC-SB upon unbinding

 drivers/gpu/nova-core/firmware/booter.rs          |   1 -
 drivers/gpu/nova-core/firmware/fwsec.rs           |   1 -
 drivers/gpu/nova-core/gpu.rs                      |  21 +++--
 drivers/gpu/nova-core/gsp/boot.rs                 | 100 +++++++++++++++++++++-
 drivers/gpu/nova-core/gsp/commands.rs             |  69 +++++++++++----
 drivers/gpu/nova-core/gsp/fw.rs                   |   4 +
 drivers/gpu/nova-core/gsp/fw/commands.rs          |  44 ++++++++++
 drivers/gpu/nova-core/gsp/fw/r570_144/bindings.rs |  11 +++
 drivers/gpu/nova-core/regs.rs                     |   5 ++
 rust/kernel/bug.rs                                |  10 +++
 10 files changed, 241 insertions(+), 25 deletions(-)
---
base-commit: b4e07588e743c989499ca24d49e752c074924a9a
change-id: 20251216-nova-unload-4029b3b76950

Best regards,
--  
Alexandre Courbot <acourbot@xxxxxxxxxx>