linux-stable.git/arch/x86/include/asm/resctrl.h, branch v6.2

x86/resctrl: Move MSR defines into msr-index.h

2022-11-27T22:00:45+00:00

msr-index.h should contain all MSRs for easier grepping for MSR numbers
when dealing with unchecked MSR access warnings, for example.

Move the resctrl ones. Prefix IA32_PQR_ASSOC with "MSR_" while at it.

No functional changes.

Signed-off-by: Borislav Petkov 
Link: https://lore.kernel.org/r/20221106212923.20699-1-bp@alien8.de

x86/resctrl: Rename and change the units of resctrl_cqm_threshold

2022-09-23T12:23:41+00:00

resctrl_cqm_threshold is stored in a hardware specific chunk size,
but exposed to user-space as bytes.

This means the filesystem parts of resctrl need to know how the hardware
counts, to convert the user provided byte value to chunks. The interface
between the architecture's resctrl code and the filesystem ought to
treat everything as bytes.

Change the unit of resctrl_cqm_threshold to bytes. resctrl_arch_rmid_read()
still returns its value in chunks, so this needs converting to bytes.
As all the users have been touched, rename the variable to
resctrl_rmid_realloc_threshold, which describes what the value is for.

Neither r->num_rmid nor hw_res->mon_scale are guaranteed to be a power
of 2, so the existing code introduces a rounding error from resctrl's
theoretical fraction of the cache usage. This behaviour is kept as it
ensures the user visible value matches the value read from hardware
when the rmid will be reallocated.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov 
Reviewed-by: Jamie Iles 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Reinette Chatre 
Tested-by: Xin Hao 
Tested-by: Shaopeng Tan 
Tested-by: Cristian Marussi 
Link: https://lore.kernel.org/r/20220902154829.30399-20-james.morse@arm.com

x86/resctrl: Apply READ_ONCE/WRITE_ONCE to task_struct.{rmid,closid}

2021-01-11T10:43:23+00:00

A CPU's current task can have its {closid, rmid} fields read locally
while they are being concurrently written to from another CPU.
This can happen anytime __resctrl_sched_in() races with either
__rdtgroup_move_task() or rdt_move_group_tasks().

Prevent load / store tearing for those accesses by giving them the
READ_ONCE() / WRITE_ONCE() treatment.

Signed-off-by: Valentin Schneider 
Signed-off-by: Reinette Chatre 
Signed-off-by: Borislav Petkov 
Link: https://lkml.kernel.org/r/9921fda88ad81afb9885b517fbe864a2bc7c35a9.1608243147.git.reinette.chatre@intel.com

x86/cpu: Move resctrl CPUID code to resctrl/

2020-05-06T15:51:21+00:00

The function determining a platform's support and properties of cache
occupancy and memory bandwidth monitoring (properties of
X86_FEATURE_CQM_LLC) can be found among the common CPU code. After
the feature's properties is populated in the per-CPU data the resctrl
subsystem is the only consumer (via boot_cpu_data).

Move the function that obtains the CPU information used by resctrl to
the resctrl subsystem and rename it from init_cqm() to
resctrl_cpu_detect(). The function continues to be called from the
common CPU code. This move is done in preparation of the addition of some
vendor specific code.

No functional change.

Suggested-by: Borislav Petkov 
Signed-off-by: Reinette Chatre 
Signed-off-by: Borislav Petkov 
Link: https://lkml.kernel.org/r/38433b99f9d16c8f4ee796f8cc42b871531fa203.1588715690.git.reinette.chatre@intel.com

x86/resctrl: Rename asm/resctrl_sched.h to asm/resctrl.h

2020-05-06T15:45:22+00:00

asm/resctrl_sched.h is dedicated to the code used for configuration
of the CPU resource control state when a task is scheduled.

Rename resctrl_sched.h to resctrl.h in preparation of additions that
will no longer make this file dedicated to work done during scheduling.

No functional change.

Suggested-by: Borislav Petkov 
Signed-off-by: Reinette Chatre 
Signed-off-by: Borislav Petkov 
Link: https://lkml.kernel.org/r/6914e0ef880b539a82a6d889f9423496d471ad1d.1588715690.git.reinette.chatre@intel.com