linux.git/arch/x86/kernel/cpu/resctrl/core.c, branch v6.15

x86/resctrl: Move get_{mon,ctrl}_domain_from_cpu() to live with their callers

2025-03-12T11:24:58+00:00

Each of get_{mon,ctrl}_domain_from_cpu() only has one caller.

Once the filesystem code is moved to /fs/, there is no equivalent to
core.c.

Move these functions to each live next to their caller. This allows
them to be made static and the header file entries to be removed.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
Reviewed-by: Babu Moger 
Reviewed-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Shaopeng Tan 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-31-james.morse@arm.com

x86/resctrl: Move RFTYPE flags to be managed by resctrl

2025-03-12T11:24:37+00:00

resctrl_file_fflags_init() is called from the architecture specific code to
make the 'thread_throttle_mode' file visible. The architecture specific code
has already set the membw.throttle_mode in the rdt_resource.

This forces the RFTYPE flags used by resctrl to be exposed to the architecture
specific code.

This doesn't need to be specific to the architecture, the throttle_mode can be
used by resctrl to determine if the 'thread_throttle_mode' file should be
visible. This allows the RFTYPE flags to be private to resctrl.

Add thread_throttle_mode_init(), and use it to call resctrl_file_fflags_init()
from resctrl_init(). This avoids publishing an extra function between the
architecture and filesystem code.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Reviewed-by: Babu Moger 
Reviewed-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Shaopeng Tan 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-28-james.morse@arm.com

x86/resctrl: Move mba_mbps_default_event init to filesystem code

2025-03-12T11:23:52+00:00

mba_mbps_default_event is initialised based on whether mbm_local or mbm_total
is supported. In the case of both, it is initialised to mbm_local.
mba_mbps_default_event is initialised in core.c's get_rdt_mon_resources(),
while all the readers are in rdtgroup.c.

After this code is split into architecture-specific and filesystem code,
get_rdt_mon_resources() remains part of the architecture code, which would
mean mba_mbps_default_event has to be exposed by the filesystem code.

Move the initialisation to the filesystem's resctrl_mon_resource_init().

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Reviewed-by: Babu Moger 
Reviewed-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Shaopeng Tan 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-22-james.morse@arm.com

x86/resctrl: Add resctrl_arch_is_evt_configurable() to abstract BMEC

2025-03-12T11:23:45+00:00

When BMEC is supported the resctrl event can be configured in a number of
ways. This depends on architecture support. rdt_get_mon_l3_config() modifies
the struct mon_evt and calls resctrl_file_fflags_init() to create the files
that allow the configuration.

Splitting this into separate architecture and filesystem parts would require
the struct mon_evt and resctrl_file_fflags_init() to be exposed.

Instead, add resctrl_arch_is_evt_configurable(), and use this from
resctrl_mon_resource_init() to initialise struct mon_evt and call
resctrl_file_fflags_init().

resctrl_arch_is_evt_configurable() calls rdt_cpu_has() so it doesn't obviously
benefit from being inlined. Putting it in core.c will allow rdt_cpu_has() to
eventually become static.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
Reviewed-by: Babu Moger 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-20-james.morse@arm.com

x86/resctrl: Move the is_mbm_*_enabled() helpers to asm/resctrl.h

2025-03-12T11:23:33+00:00

The architecture specific parts of resctrl provide helpers like
is_mbm_total_enabled() and is_mbm_local_enabled() to hide accesses to the
rdt_mon_features bitmap.

Exposing a group of helpers between the architecture and filesystem code is
preferable to a single unsigned-long like rdt_mon_features. Helpers can be more
readable and have a well defined behaviour, while allowing architectures to hide
more complex behaviour.

Once the filesystem parts of resctrl are moved, these existing helpers can no
longer live in internal.h. Move them to include/linux/resctrl.h Once these are
exposed to the wider kernel, they should have a 'resctrl_arch_' prefix, to fit
the rest of the arch<->fs interface.

Move and rename the helpers that touch rdt_mon_features directly. is_mbm_event()
and is_mbm_enabled() are only called from rdtgroup.c, so can be moved into that
file.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Tony Luck 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
Reviewed-by: Babu Moger 
Reviewed-by: Shaopeng Tan 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-19-james.morse@arm.com

x86/resctrl: Move monitor exit work to a resctrl exit call

2025-03-12T11:23:13+00:00

rdt_put_mon_l3_config() is called via the architecture's resctrl_arch_exit()
call, and appears to free the rmid_ptrs[] and closid_num_dirty_rmid[] arrays.
In reality this code is marked __exit, and is removed by the linker as resctrl
can't be built as a module.

To separate the filesystem and architecture parts of resctrl, this free()ing
work needs to be triggered by the filesystem, as these structures belong to
the filesystem code.

Rename rdt_put_mon_l3_config() to resctrl_mon_resource_exit() and call it from
resctrl_exit(). The kfree() is currently dependent on r->mon_capable.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Reviewed-by: Babu Moger 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-16-james.morse@arm.com

x86/resctrl: Move rdt_find_domain() to be visible to arch and fs code

2025-03-12T11:22:56+00:00

rdt_find_domain() finds a domain given a resource and a cache-id.  This is
used by both the architecture code and the filesystem code.

After the filesystem code moves to live in /fs/, this helper is either
duplicated by all architectures, or needs exposing by the filesystem code.

Add the declaration to the global header file. As it's now globally visible,
and has only a handful of callers, swap the 'rdt' for 'resctrl'. Move the
function to live with its caller in ctrlmondata.c as the filesystem code will
not have anything corresponding to core.c.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
Reviewed-by: Babu Moger 
Reviewed-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Shaopeng Tan 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-13-james.morse@arm.com

x86/resctrl: Expose resctrl fs's init function to the rest of the kernel

2025-03-12T11:22:54+00:00

rdtgroup_init() needs exposing to the rest of the kernel so that arch code can
call it once it lives in core code. As this is one of the few functions
exposed, rename it to have "resctrl" in the name. The same goes for the exit
call.

Rename x86's arch code init functions for RDT to have an arch prefix to make
it clear these are part of the architecture code.

Co-developed-by: Dave Martin 
Signed-off-by: Dave Martin 
Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Reviewed-by: Babu Moger 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-12-james.morse@arm.com

x86/resctrl: Generate default_ctrl instead of sharing it

2025-03-12T11:22:44+00:00

The struct rdt_resource default_ctrl is used by both the architecture code for
resetting the hardware controls, and sometimes by the filesystem code as the
default value for the schema, unless the bandwidth software controller is in
use.

Having the default exposed by the architecture code causes unnecessary
duplication for each architecture as the default value must be specified, but
can be derived from other schema properties. Now that the maximum bandwidth is
explicitly described, resctrl can derive the default value from the schema
format and the other resource properties.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
Reviewed-by: Babu Moger 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-9-james.morse@arm.com

x86/resctrl: Add max_bw to struct resctrl_membw

2025-03-12T11:22:41+00:00

__rdt_get_mem_config_amd() and __get_mem_config_intel() both use the
default_ctrl property as a maximum value. This is because the MBA schema works
differently between these platforms. Doing this complicates determining
whether the default_ctrl property belongs to the arch code, or can be derived
from the schema format.

Deriving the maximum or default value from the schema format would avoid the
architecture code having to tell resctrl such obvious things as the maximum
percentage is 100, and the maximum bitmap is all ones.

Maximum bandwidth is always going to vary per platform. Add max_bw as
a special case. This is currently used for the maximum MBA percentage on Intel
platforms, but can be removed from the architecture code if 'percentage'
becomes a schema format resctrl supports directly.

This value isn't needed for other schema formats.

This will allow the default_ctrl to be generated from the schema properties
when it is needed.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Reviewed-by: Babu Moger 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-8-james.morse@arm.com