linux.git/arch/x86/kernel/cpu/resctrl/ctrlmondata.c, branch v6.14

x86/resctrl: Add write option to "mba_MBps_event" file

2024-12-12T10:27:37+00:00

The "mba_MBps" mount option provides an alternate method to control memory
bandwidth. Instead of specifying allowable bandwidth as a percentage of
maximum possible, the user provides a MiB/s limit value.

There is a file in each CTRL_MON group directory that shows the event
currently in use.

Allow writing that file to choose a different event.

A user can choose any of the memory bandwidth monitoring events listed in
/sys/fs/resctrl/info/L3_mon/mon_features independently for each CTRL_MON group
by writing to each of the "mba_MBps_event" files.

Signed-off-by: Tony Luck 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20241206163148.83828-8-tony.luck@intel.com

x86/resctrl: Add "mba_MBps_event" file to CTRL_MON directories

2024-12-12T10:27:28+00:00

The "mba_MBps" mount option provides an alternate method to control memory
bandwidth. Instead of specifying allowable bandwidth as a percentage of
maximum possible, the user provides a MiB/s limit value.

In preparation to allow the user to pick the memory bandwidth monitoring event
used as input to the feedback loop, provide a file in each CTRL_MON group
directory that shows the event currently in use. Note that this file is only
visible when the "mba_MBps" mount option is in use.

Suggested-by: Reinette Chatre 
Signed-off-by: Tony Luck 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20241206163148.83828-7-tony.luck@intel.com

x86/resctrl: Avoid overflow in MB settings in bw_validate()

2024-10-08T14:17:38+00:00

The resctrl schemata file supports specifying memory bandwidth associated with
the Memory Bandwidth Allocation (MBA) feature via a percentage (this is the
default) or bandwidth in MiBps (when resctrl is mounted with the "mba_MBps"
option).

The allowed range for the bandwidth percentage is from
/sys/fs/resctrl/info/MB/min_bandwidth to 100, using a granularity of
/sys/fs/resctrl/info/MB/bandwidth_gran. The supported range for the MiBps
bandwidth is 0 to U32_MAX.

There are two issues with parsing of MiBps memory bandwidth:

* The user provided MiBps is mistakenly rounded up to the granularity
  that is unique to percentage input.

* The user provided MiBps is parsed using unsigned long (thus accepting
  values up to ULONG_MAX), and then assigned to u32 that could result in
  overflow.

Do not round up the MiBps value and parse user provided bandwidth as the u32
it is intended to be. Use the appropriate kstrtou32() that can detect out of
range values.

Fixes: 8205a078ba78 ("x86/intel_rdt/mba_sc: Add schemata support")
Fixes: 6ce1560d35f6 ("x86/resctrl: Switch over to the resctrl mbps_val list")
Co-developed-by: Reinette Chatre 
Signed-off-by: Reinette Chatre 
Signed-off-by: Martin Kletzander 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Reviewed-by: Tony Luck

x86/resctrl: Fill out rmid_read structure for smp_call*() to read a counter

2024-07-02T17:57:19+00:00

mon_event_read() fills out most fields of the struct rmid_read that is passed
via an smp_call*() function to a CPU that is part of the correct domain to
read the monitor counters.

With Sub-NUMA Cluster (SNC) mode there are now two cases to handle:

1) Reading a file that returns a value for a single domain.
   + Choose the CPU to execute from the domain cpu_mask

2) Reading a file that must sum across domains sharing an L3 cache
   instance.
   + Indicate to called code that a sum is needed by passing a NULL
     rdt_mon_domain pointer.
   + Choose the CPU from the L3 shared_cpu_map.

Signed-off-by: Tony Luck 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20240628215619.76401-16-tony.luck@intel.com

x86/resctrl: Initialize on-stack struct rmid_read instances

2024-07-02T17:49:54+00:00

New semantics rely on some struct rmid_read members having NULL values to
distinguish between the SNC and non-SNC scenarios.  resctrl can thus no longer
rely on this struct not being initialized properly.

Initialize all on-stack declarations of struct rmid_read:

  rdtgroup_mondata_show()
  mbm_update()
  mkdir_mondata_subdir()

to ensure that garbage values from the stack are not passed down to other
functions.

  [ bp: Massage commit message. ]

Signed-off-by: Tony Luck 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20240628215619.76401-11-tony.luck@intel.com

x86/resctrl: Split the rdt_domain and rdt_hw_domain structures

2024-07-02T17:49:54+00:00

The same rdt_domain structure is used for both control and monitor
functions. But this results in wasted memory as some of the fields are
only used by control functions, while most are only used for monitor
functions.

Split into separate rdt_ctrl_domain and rdt_mon_domain structures with
just the fields required for control and monitoring respectively.

Similar split of the rdt_hw_domain structure into rdt_hw_ctrl_domain
and rdt_hw_mon_domain.

Signed-off-by: Tony Luck 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20240628215619.76401-5-tony.luck@intel.com

x86/resctrl: Prepare for different scope for control/monitor operations

2024-07-02T17:49:53+00:00

Resctrl assumes that control and monitor operations on a resource are
performed at the same scope.

Prepare for systems that use different scope (specifically Intel needs
to split the RDT_RESOURCE_L3 resource to use L3 scope for cache control
and NODE scope for cache occupancy and memory bandwidth monitoring).

Create separate domain lists for control and monitor operations.

Note that errors during initialization of either control or monitor
functions on a domain would previously result in that domain being
excluded from both control and monitor operations. Now the domains are
allocated independently it is no longer required to disable both control
and monitor operations if either fail.

Signed-off-by: Tony Luck 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20240628215619.76401-4-tony.luck@intel.com

x86/resctrl: Prepare to split rdt_domain structure

2024-07-02T17:49:53+00:00

The rdt_domain structure is used for both control and monitor features.
It is about to be split into separate structures for these two usages
because the scope for control and monitoring features for a resource
will be different for future resources.

To allow for common code that scans a list of domains looking for a
specific domain id, move all the common fields ("list", "id", "cpu_mask")
into their own structure within the rdt_domain structure.

Signed-off-by: Tony Luck 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20240628215619.76401-3-tony.luck@intel.com

x86/resctrl: Prepare for new domain scope

2024-07-02T17:49:53+00:00

Resctrl resources operate on subsets of CPUs in the system with the
defining attribute of each subset being an instance of a particular
level of cache. E.g. all CPUs sharing an L3 cache would be part of the
same domain.

In preparation for features that are scoped at the NUMA node level,
change the code from explicit references to "cache_level" to a more
generic scope. At this point the only options for this scope are groups
of CPUs that share an L2 cache or L3 cache.

Clean up the error handling when looking up domains. Report invalid ids
before calling rdt_find_domain() in preparation for better messages when
scope can be other than cache scope. This means that rdt_find_domain()
will never return an error. So remove checks for error from the call sites.

Signed-off-by: Tony Luck 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20240628215619.76401-2-tony.luck@intel.com

x86/resctrl: Simplify call convention for MSR update functions

2024-04-24T11:47:00+00:00

The per-resource MSR update functions cat_wrmsr(), mba_wrmsr_intel(),
and mba_wrmsr_amd() all take three arguments:

  (struct rdt_domain *d, struct msr_param *m, struct rdt_resource *r)

struct msr_param contains pointers to both struct rdt_resource and struct
rdt_domain, thus only struct msr_param is necessary.

Pass struct msr_param as a single parameter. Clean up formatting and
fix some fir tree declaration ordering.

No functional change.

Suggested-by: Reinette Chatre 
Signed-off-by: Tony Luck 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Reviewed-by: Babu Moger 
Tested-by: Maciej Wieczor-Retman 
Link: https://lore.kernel.org/r/20240308213846.77075-3-tony.luck@intel.com