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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Jan 2026 21:14:28.6021 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: e26cb46b-441c-4e79-ea59-08de5932101d X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: SJ1PEPF00001CE4.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA3PR12MB7879 Content-Type: text/plain; charset="utf-8" Add a new resctrl info file, plza_capable, to report whether a resource supports the PLZA capability. Allows user to query PLZA support directly through resctrl without having to infer it from other resource attributes. Signed-off-by: Babu Moger --- Documentation/filesystems/resctrl.rst | 17 +++++++++++++++++ fs/resctrl/rdtgroup.c | 17 +++++++++++++++++ 2 files changed, 34 insertions(+) diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesyst= ems/resctrl.rst index 3d66814a1d7f..1de55b5cb0e3 100644 --- a/Documentation/filesystems/resctrl.rst +++ b/Documentation/filesystems/resctrl.rst @@ -30,6 +30,7 @@ ABMC (Assignable Bandwidth Monitoring Counters) "" SDCIAE (Smart Data Cache Injection Allocation Enforcement) "" GMBA (Global Memory Bandwidth Allocation) "" GSMBA (Global Slow Memory Bandwidth Allocation) "" +PLZA (Privilege Level Zero association) "" =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 Historically, new features were made visible by default in /proc/cpuinfo. = This @@ -151,6 +152,22 @@ related to allocation: "1": Non-contiguous 1s value in CBM is supported. =20 +"plza_capable": + Indicates the availability of Privilege Level Zero Associa= tion (PLZA). + PLZA is a hardware feature that enables automatic associat= ion of execution + at Privilege Level Zero (CPL=3D0) with a designated Class = of Service + Identifier (CLOSID) and/or Resource Monitoring Identifier = (RMID). + This mechanism allows the system to override the default p= er-thread + association for threads operating at CPL=3D0 when necessar= y. Additionally, + PLZA provides configuration capabilities for defining a de= dicated resource + control group and assigning CPUs and tasks to operate unde= r CLOSID + constraints reserved exclusively for PLZA. + + "1": + Resource supports the feature. + "0": + Support not available for this resource. + "io_alloc": "io_alloc" enables system software to configure the portion of the cache allocated for I/O traffic. File may only exist if the diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c index fc034f4481e3..d773bf77bcc6 100644 --- a/fs/resctrl/rdtgroup.c +++ b/fs/resctrl/rdtgroup.c @@ -1260,6 +1260,16 @@ static ssize_t max_threshold_occ_write(struct kernfs= _open_file *of, return nbytes; } =20 +static int rdt_plza_show(struct kernfs_open_file *of, struct seq_file *seq= , void *v) +{ + struct resctrl_schema *s =3D rdt_kn_parent_priv(of->kn); + struct rdt_resource *r =3D s->res; + + seq_printf(seq, "%d\n", r->plza_capable); + + return 0; +} + /* * rdtgroup_mode_show - Display mode of this resource group */ @@ -1991,6 +2001,13 @@ static struct rftype res_common_files[] =3D { .seq_show =3D rdt_delay_linear_show, .fflags =3D RFTYPE_CTRL_INFO | RFTYPE_RES_MB, }, + { + .name =3D "plza_capable", + .mode =3D 0444, + .kf_ops =3D &rdtgroup_kf_single_ops, + .seq_show =3D rdt_plza_show, + .fflags =3D RFTYPE_CTRL_INFO, + }, /* * Platform specific which (if any) capabilities are provided by * thread_throttle_mode. Defer "fflags" initialization to platform --=20 2.34.1