CKI KWF Bot 13a5607816 Merge: drm/xe: gate observation streams properly
MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-10/-/merge_requests/3204

JIRA: https://redhat.atlassian.net/browse/RHEL-212122

xe OA and EU-stall paths open-code a partial copy of the system-wide
perf CPU-event permission check:

    if (xe_observation_paranoid && !perfmon_capable())
            return -EACCES;

This open-coded check skips two things perf_allow_cpu() handles: the
graduated kernel.perf_event_paranoid policy that an administrator
may have tuned, and the security_perf_event_open() LSM hook.

Introduce xe_observation_paranoid_check() to wrap perf_allow_cpu(),
and convert the open-coded sites in xe_oa.c and xe_eu_stall.c. The
dev.xe.observation_paranoid sysctl still acts as an escape hatch
when cleared.

xe observation now consults kernel.perf_event_paranoid and the LSM
perf hook on every open. Sites that have already configured an LSM
perf policy or tuned the paranoid sysctl will see those settings
extend to xe.

Signed-off-by: Michael Petlan <mpetlan@redhat.com>

Approved-by: ashelat <ashelat@redhat.com>
Approved-by: tallison1 <tallison@redhat.com>
Approved-by: Gary Guo <gguo@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: CKI GitLab Kmaint Pipeline Bot <26919896-cki-kmaint-pipeline-bot@users.noreply.gitlab.com>
2026-08-20 09:14:55 +00:00
2026-08-18 06:06:11 -04:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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