On current platforms with multiple GTs, all of the GT IDs are
consecutive; as a result we know that the GT IDs range from 0 to
gt_count-1 and can determine if a GT ID is valid by comparing against
the count. The consecutive nature of GT IDs may not hold true on future
platforms if/when we have platforms that are both multi-tile and have
multiple GTs within each tile. Once such platforms exist, it's quite
possible that we could wind up with something like a GT list composed of
IDs 0, 2, and 3 with no GT 1 (which would be a 2-tile platform with
media only on the second tile).
To future-proof the code we should stop comparing against the GT count
to determine whether a GT ID is valid or not. Instead we should do an
actual lookup of the ID to determine whether the GT exists. This also
means that our GT loop macro should not end at the GT count, but should
rather examine the entire space up to (# of tiles) * (max GT per tile)
to ensure it doesn't stop prematurely.
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Link: https://lore.kernel.org/r/20250701201320.2514369-15-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
copy_from_user() has more checks and is more safer than
__copy_from_user()
Suggested-by: Kees Cook <kees@kernel.org>
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://lore.kernel.org/r/acabf20aa8621c7bc8de09b1bffb8d14b5376484.1746126614.git.harish.chegondi@intel.com
EU stall sampling is not supported on SRIOV VF. Do not
initialize or open EU stall stream on SRIOV VF.
Fixes: 9a0b11d4cf ("drm/xe/eustall: Add support to init, enable and disable EU stall sampling")
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://lore.kernel.org/r/10db5d1c7e17aadca7078ff74575b7ffc0d5d6b8.1745215022.git.harish.chegondi@intel.com
Use a separate lock in the polling function eu_stall_data_buf_poll()
instead of eu_stall->stream_lock. This would prevent a possible
circular locking dependency leading to a deadlock as described below.
This would also require additional locking with the new lock in
the read function.
<4> [787.192986] ======================================================
<4> [787.192988] WARNING: possible circular locking dependency detected
<4> [787.192991] 6.14.0-rc7-xe+ #1 Tainted: G U
<4> [787.192993] ------------------------------------------------------
<4> [787.192994] xe_eu_stall/20093 is trying to acquire lock:
<4> [787.192996] ffff88819847e2c0 ((work_completion)
(&(&stream->buf_poll_work)->work)), at: __flush_work+0x1f8/0x5e0
<4> [787.193005] but task is already holding lock:
<4> [787.193007] ffff88814ce83ba8 (>->eu_stall->stream_lock){3:3},
at: xe_eu_stall_stream_ioctl+0x41/0x6a0 [xe]
<4> [787.193090] which lock already depends on the new lock.
<4> [787.193093] the existing dependency chain (in reverse order) is:
<4> [787.193095]
-> #1 (>->eu_stall->stream_lock){+.+.}-{3:3}:
<4> [787.193099] __mutex_lock+0xb4/0xe40
<4> [787.193104] mutex_lock_nested+0x1b/0x30
<4> [787.193106] eu_stall_data_buf_poll_work_fn+0x44/0x1d0 [xe]
<4> [787.193155] process_one_work+0x21c/0x740
<4> [787.193159] worker_thread+0x1db/0x3c0
<4> [787.193161] kthread+0x10d/0x270
<4> [787.193164] ret_from_fork+0x44/0x70
<4> [787.193168] ret_from_fork_asm+0x1a/0x30
<4> [787.193172]
-> #0 ((work_completion)(&(&stream->buf_poll_work)->work)){+.+.}-{0:0}:
<4> [787.193176] __lock_acquire+0x1637/0x2810
<4> [787.193180] lock_acquire+0xc9/0x300
<4> [787.193183] __flush_work+0x219/0x5e0
<4> [787.193186] cancel_delayed_work_sync+0x87/0x90
<4> [787.193189] xe_eu_stall_disable_locked+0x9a/0x260 [xe]
<4> [787.193237] xe_eu_stall_stream_ioctl+0x5b/0x6a0 [xe]
<4> [787.193285] __x64_sys_ioctl+0xa4/0xe0
<4> [787.193289] x64_sys_call+0x131e/0x2650
<4> [787.193292] do_syscall_64+0x91/0x180
<4> [787.193295] entry_SYSCALL_64_after_hwframe+0x76/0x7e
<4> [787.193299]
other info that might help us debug this:
<4> [787.193302] Possible unsafe locking scenario:
<4> [787.193304] CPU0 CPU1
<4> [787.193305] ---- ----
<4> [787.193306] lock(>->eu_stall->stream_lock);
<4> [787.193308] lock((work_completion)
(&(&stream->buf_poll_work)->work));
<4> [787.193311] lock(>->eu_stall->stream_lock);
<4> [787.193313] lock((work_completion)
(&(&stream->buf_poll_work)->work));
<4> [787.193315]
*** DEADLOCK ***
Fixes: 760edec939 ("drm/xe/eustall: Add support to read() and poll() EU stall data")
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/4598
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://lore.kernel.org/r/c896932fca84f79db2df5942911997ed77b2b9b6.1744934656.git.harish.chegondi@intel.com
If devm_add_action_or_reset() isn't successful, xe_eu_stall_fini()
is invoked. So, unsuccessful return from devm_add_action_or_reset()
shouldn't dereference gt->eu_stall as xe_eu_stall_fini() already
frees it. Fix this issue.
Fixes: 9a0b11d4cf ("drm/xe/eustall: Add support to init, enable and disable EU stall sampling")
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/eae49a414a7314921108e0388810aaee6261ad92.1741800396.git.harish.chegondi@intel.com
User space can get the EU stall data record size, EU stall capabilities,
EU stall sampling rates, and per XeCore buffer size with query IOCTL
DRM_IOCTL_XE_DEVICE_QUERY with .query set to DRM_XE_DEVICE_QUERY_EU_STALL.
A struct drm_xe_query_eu_stall will be returned to the user space along
with an array of supported sampling rates sorted in the fastest sampling
rate first order. sampling_rates in struct drm_xe_query_eu_stall will
point to the array of sampling rates.
Any capabilities in EU stall sampling as of this patch are considered
as base capabilities. New capability bits will be added for any new
functionality added later.
v12: Rename has_eu_stall_sampling_support() to
xe_eu_stall_supported_on_platform() and move it to header file.
v11: Check if EU stall sampling is supported on the platform.
v10: Change comments and variable names as per feedback
v9: Move reserved fields above num_sampling_rates in
struct drm_xe_query_eu_stall.
v7: Change sampling_rates from a pointer to flexible array.
v6: Include EU stall sampling rates information and
per XeCore buffer size in the query information.
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/67ba42796a5a99d648239c315694cd222812a49b.1740533885.git.harish.chegondi@intel.com
Add EU stall sampling support for Xe2 architecture GPUs - LNL and BMG.
EU stall data format for LNL and BMG is different from that of PVC.
v10: Update comments as per review feedback
v9: Use GRAPHICS_VER() check instead of platform
v8: Renamed struct drm_xe_eu_stall_data_xe2 to struct xe_eu_stall_data_xe2
since it is a local structure.
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/d85093e9ab1204d14d2cc783f304a4bc8688951c.1740533885.git.harish.chegondi@intel.com
If the user space doesn't read the EU stall data fast enough,
it is possible that the EU stall data buffer can get filled,
and if the hardware wants to write more data, it simply drops
data due to unavailable buffer space. In that case, hardware
sets a bit in a register. If the driver detects data drop,
the driver read() returns -EIO error to let the user space
know that HW has dropped data. The -EIO error is returned
even if there is EU stall data in the buffer. A subsequent
read by the user space returns the remaining EU stall data.
v12: Move 'goto exit_drop;' to the next
'if (read_data_size == 0)' statement.
v11: Clear drop bit even for empty data buffer as the data
was read from the buffer in the previous read.
v10: Reverted the changes back to v8:
Clear the drop bits only after reading the data.
v9: Move all data drop handling code to this patch
Clear all drop data bits before returning -EIO.
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/6fbfd7cfa42cb3ef5515b6412573d74c7cd3d27a.1740533885.git.harish.chegondi@intel.com
Implement the EU stall sampling APIs to read() and poll() EU stall data.
A work function periodically polls the EU stall data buffer write pointer
registers to look for any new data and caches the write pointer. The read
function compares the cached read and write pointers and copies any new
data to the user space.
v11: Used gt->eu_stall->stream_lock instead of stream->buf_lock.
Removed read and write offsets from trace and added read size.
Moved workqueue from struct xe_eu_stall_data_stream to
struct xe_eu_stall_gt.
v10: Used cancel_delayed_work_sync() instead of flush_delayed_work()
Replaced per xecore lock with a lock for all the xecore buffers
Code movement and optimizations as per review feedback
v9: New patch split from the previous patch.
Used *_delayed_work functions instead of hrtimer
Addressed the review feedback in read and poll functions
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/369dee85a3b6bd2c08aeae89ca55e66a9a0242d2.1740533885.git.harish.chegondi@intel.com
Implement EU stall sampling APIs introduced in the previous patch for
Xe_HPC (PVC). Add register definitions and the code that accesses these
registers to the APIs.
Add initialization and clean up functions and their implementations,
EU stall enable and disable functions.
v11: Move stream->xecore_buf alloc to xe_eu_stall_data_buf_alloc().
Register xe_eu_stall_fini() with devm_add_action_or_reset()
instead of calling it from xe_gt_fini().
Changed a couple of variables in struct xe_eu_stall_data_stream
from unsigned int to int.
v10: Fixed error rewinding code
Moved code around as per review feedback
v9: Moved structure definitions from xe_eu_stall.h to xe_eu_stall.c
Moved read and poll implementations to the next patch
Used xe_bo_create_pin_map_at_aligned instead of xe_bo_create_pin_map
Changed lock names as per review feedback
Moved drop data handling into a subsequent patch
Moved code around as per review feedback
v8: Updated copyright year in xe_eu_stall_regs.h to 2025.
Renamed struct drm_xe_eu_stall_data_pvc to struct xe_eu_stall_data_pvc
since it is a local structure.
v6: Fix buffer wrap around over write bug (Matt Olson)
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/b6aeca593d521828a0b4fbf6cfd2844716c4fc66.1740533885.git.harish.chegondi@intel.com
A new hardware feature first introduced in PVC gives capability to
periodically sample EU stall state and record counts for different stall
reasons, on a per IP basis, aggregate across all EUs in a subslice and
record the samples in a buffer in each subslice. Eventually, the aggregated
data is written out to a buffer in the memory. This feature is also
supported in XE2 and later architecture GPUs.
Use an existing IOCTL - DRM_IOCTL_XE_OBSERVATION as the interface into the
driver from the user space to do initial setup and obtain a file descriptor
for the EU stall data stream. Input parameter to the IOCTL is a struct
drm_xe_observation_param in which observation_type should be set to
DRM_XE_OBSERVATION_TYPE_EU_STALL, observation_op should be
DRM_XE_OBSERVATION_OP_STREAM_OPEN and param should point to a chain of
drm_xe_ext_set_property structures in which each structure has a pair of
property and value. The EU stall sampling input properties are defined in
drm_xe_eu_stall_property_id enum.
With the file descriptor obtained from DRM_IOCTL_XE_OBSERVATION, user space
can enable and disable EU stall sampling with the IOCTLs:
DRM_XE_OBSERVATION_IOCTL_ENABLE and DRM_XE_OBSERVATION_IOCTL_DISABLE.
User space can also call poll() to check for availability of data in the
buffer. The data can be read with read(). Finally, the file descriptor
can be closed with close().
v11: Changed a couple of variables in struct eu_stall_open_properties
from unsigned int to int.
v10: Use extension number while parsing chain of extensions.
Remove function description for static functions.
Move code around as per review feedback.
v9: Changed some u32 to unsigned int.
Moved some code around as per review feedback from v8.
v8: Used div_u64 instead of / to fix 32-bit build issue.
Changed copyright year in xe_eu_stall.c/h to 2025.
v7: Renamed input property DRM_XE_EU_STALL_PROP_EVENT_REPORT_COUNT
to DRM_XE_EU_STALL_PROP_WAIT_NUM_REPORTS to be consistent with
OA. Renamed the corresponding internal variables.
Fixed some commit messages based on review feedback.
v6: Change the input sampling rate to GPU cycles instead of
GPU cycles multiplier.
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/bb707a27975c33e4a912b9839b023acb7a1f9c90.1740533885.git.harish.chegondi@intel.com
