On 13/06/2022 16:39, Ceraolo Spurio, Daniele wrote:
On 6/13/2022 1:16 AM, Tvrtko Ursulin wrote:
On 10/06/2022 00:19, Daniele Ceraolo Spurio wrote:
On DG2, HuC loading is performed by the GSC, via a PXP command. The load
operation itself is relatively simple (just send a message to the GSC
with the physical address of the HuC in LMEM), but there are timing
changes that requires special attention. In particular, to send a PXP
command we need to first export the GSC driver and then wait for the
mei-gsc and mei-pxp modules to start, which means that HuC load will
complete after i915 load is complete. This means that there is a small
window of time after i915 is registered and before HuC is loaded
during which userspace could submit and/or checking the HuC load status,
although this is quite unlikely to happen (HuC is usually loaded before
kernel init/resume completes).
We've consulted with the media team in regards to how to handle this and
they've asked us to do the following:
1) Report HuC as loaded in the getparam IOCTL even if load is still in
progress. The media driver uses the IOCTL as a way to check if HuC is
enabled and then includes a secondary check in the batches to get the
actual status, so doing it this way allows userspace to keep working
without changes.
2) Stall all userspace VCS submission until HuC is loaded. Stalls are
expected to be very rare (if any), due to the fact that HuC is usually
loaded before kernel init/resume is completed.
Motivation to add these complications into i915 are not clear to me
here. I mean there is no HuC on DG2 _yet_ is the premise of the
series, right? So no backwards compatibility concerns. In this case
why jump through the hoops and not let userspace handle all of this by
just leaving the getparam return the true status?
The main areas impacted by the fact that we can't guarantee that HuC
load is complete when i915 starts accepting submissions are boot and
suspend/resume, with the latter being the main problem; GT reset is not
a concern because HuC now survives it. A suspend/resume can be
transparent to userspace and therefore the HuC status can temporarily
flip from loaded to not without userspace knowledge, especially if we
start going into deeper suspend states and start causing HuC resets when
we go into runtime suspend. Note that this is different from what
happens during GT reset for older platforms, because in that scenario we
guarantee that HuC reload is complete before we restart the submission
back-end, so userspace doesn't notice that the HuC status change. We had
an internal discussion about this problem with both media and i915 archs
and the conclusion was that the best option is for i915 to stall media
submission while HuC (re-)load is in progress.
Resume is potentialy a good reason - I did not pick up on that from the
cover letter. I read the statement about the unlikely and small window
where HuC is not loaded during kernel init/resume and I guess did not
pick up on the resume part.
Waiting for GSC to load HuC from i915 resume is not an option?
Will there be runtime suspend happening on the GSC device behind i915's
back, or i915 and GSC will always be able to transition the states in
tandem?
Regards,
Tvrtko
Implementation-wise, this turned out a bit more complicated than
expected due to the required tracking of the mei-gsc status to enforce
the timeouts. When I discussed this with the mei team they suggested
using the notifier for that, which is what I went with. Another option I
considered was to start a timer when the first media submission comes in
while HuC load is in progress and stall for the maximum expected HuC
load time; this would be more error prone, hence why I preferred the
notifier option, but would be simpler. I'm open to other options here if
you have any better ideas.
Thanks,
Daniele
Regards,
Tvrtko
Timeouts are in place to ensure all submissions are unlocked in case
something goes wrong. Since we need to monitor the status of the mei
driver to know what's happening and when to time out, a notifier has
been added so we get a callback when the status of the mei driver
changes.
Note that this series depends on the GSC support for DG2 [1], which has
been included squashed in a single patch.
[1]: https://patchwork.freedesktop.org/series/102339/
Cc: Alan Previn <alan.previn.teres.alexis@xxxxxxxxx>
Cc: Tony Ye <tony.ye@xxxxxxxxx>
Cc: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
Daniele Ceraolo Spurio (8):
HAX: mei: GSC support for XeHP SDV and DG2 platform
drm/i915/pxp: load the pxp module when we have a gsc-loaded huc
drm/i915/dg2: setup HuC loading via GSC
drm/i915/huc: track delayed HuC load with a fence
drm/i915/huc: stall media submission until HuC is loaded
drm/i915/huc: report HuC as loaded even if load still in progress
drm/i915/huc: define gsc-compatible HuC fw for DG2
HAX: drm/i915: force INTEL_MEI_GSC and INTEL_MEI_PXP on for CI
Tomas Winkler (4):
mei: add support to GSC extended header
mei: bus: enable sending gsc commands
mei: pxp: support matching with a gfx discrete card
drm/i915/pxp: add huc authentication and loading command
Vitaly Lubart (3):
mei: bus: extend bus API to support command streamer API
mei: pxp: add command streamer API to the PXP driver
drm/i915/pxp: implement function for sending tee stream command
drivers/gpu/drm/i915/Kconfig.debug | 2 +
drivers/gpu/drm/i915/Makefile | 11 +-
drivers/gpu/drm/i915/gt/intel_gsc.c | 141 +++++++++-
drivers/gpu/drm/i915/gt/intel_gsc.h | 3 +
drivers/gpu/drm/i915/gt/uc/intel_huc.c | 244 ++++++++++++++++--
drivers/gpu/drm/i915/gt/uc/intel_huc.h | 27 ++
drivers/gpu/drm/i915/gt/uc/intel_huc_fw.c | 34 +++
drivers/gpu/drm/i915/gt/uc/intel_huc_fw.h | 1 +
drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c | 64 +++--
drivers/gpu/drm/i915/i915_request.c | 24 ++
drivers/gpu/drm/i915/pxp/intel_pxp.c | 32 ++-
drivers/gpu/drm/i915/pxp/intel_pxp.h | 32 ---
drivers/gpu/drm/i915/pxp/intel_pxp_huc.c | 69 +++++
drivers/gpu/drm/i915/pxp/intel_pxp_huc.h | 15 ++
drivers/gpu/drm/i915/pxp/intel_pxp_irq.h | 8 +
drivers/gpu/drm/i915/pxp/intel_pxp_session.c | 8 +-
drivers/gpu/drm/i915/pxp/intel_pxp_session.h | 11 +-
drivers/gpu/drm/i915/pxp/intel_pxp_tee.c | 138 +++++++++-
drivers/gpu/drm/i915/pxp/intel_pxp_tee.h | 5 +
.../drm/i915/pxp/intel_pxp_tee_interface.h | 21 ++
drivers/gpu/drm/i915/pxp/intel_pxp_types.h | 6 +
drivers/misc/mei/bus-fixup.c | 105 +++++---
drivers/misc/mei/bus.c | 145 ++++++++++-
drivers/misc/mei/client.c | 69 +++--
drivers/misc/mei/debugfs.c | 17 ++
drivers/misc/mei/gsc-me.c | 77 +++++-
drivers/misc/mei/hbm.c | 25 +-
drivers/misc/mei/hw-me-regs.h | 7 +
drivers/misc/mei/hw-me.c | 123 +++++++--
drivers/misc/mei/hw-me.h | 14 +-
drivers/misc/mei/hw-txe.c | 2 +-
drivers/misc/mei/hw.h | 62 +++++
drivers/misc/mei/init.c | 21 +-
drivers/misc/mei/interrupt.c | 47 +++-
drivers/misc/mei/main.c | 2 +-
drivers/misc/mei/mei_dev.h | 33 +++
drivers/misc/mei/mkhi.h | 57 ++++
drivers/misc/mei/pci-me.c | 2 +-
drivers/misc/mei/pxp/mei_pxp.c | 40 ++-
include/drm/i915_pxp_tee_interface.h | 5 +
include/linux/mei_aux.h | 2 +
include/linux/mei_cl_bus.h | 6 +
42 files changed, 1537 insertions(+), 220 deletions(-)
create mode 100644 drivers/gpu/drm/i915/pxp/intel_pxp_huc.c
create mode 100644 drivers/gpu/drm/i915/pxp/intel_pxp_huc.h
create mode 100644 drivers/misc/mei/mkhi.h
