]> git.ipfire.org Git - thirdparty/linux.git/commit
x86/resctrl: Pass domain to target CPU
authorTony Luck <tony.luck@intel.com>
Fri, 8 Mar 2024 21:38:45 +0000 (13:38 -0800)
committerBorislav Petkov (AMD) <bp@alien8.de>
Wed, 24 Apr 2024 11:41:41 +0000 (13:41 +0200)
commite3ca96e479c91d6ee657d3caa5092a6a3a620f9f
tree078017617249dc7548fb9c1cc64136c4cddbb11e
parented30a4a51bb196781c8058073ea720133a65596f
x86/resctrl: Pass domain to target CPU

reset_all_ctrls() and resctrl_arch_update_domains() use on_each_cpu_mask()
to call rdt_ctrl_update() on potentially one CPU from each domain.

But this means rdt_ctrl_update() needs to figure out which domain to
apply changes to. Doing so requires a search of all domains in a resource,
which can only be done safely if cpus_lock is held. Both callers do hold
this lock, but there isn't a way for a function called on another CPU
via IPI to verify this.

Commit

  c0d848fcb09d ("x86/resctrl: Remove lockdep annotation that triggers
  false positive")

removed the incorrect assertions.

Add the target domain to the msr_param structure and call
rdt_ctrl_update() for each domain separately using
smp_call_function_single(). This means that rdt_ctrl_update() doesn't
need to search for the domain and get_domain_from_cpu() can safely
assert that the cpus_lock is held since the remaining callers do not use
IPI.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: James Morse <james.morse@arm.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Tested-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Link: https://lore.kernel.org/r/20240308213846.77075-2-tony.luck@intel.com
arch/x86/kernel/cpu/resctrl/core.c
arch/x86/kernel/cpu/resctrl/ctrlmondata.c
arch/x86/kernel/cpu/resctrl/internal.h
arch/x86/kernel/cpu/resctrl/rdtgroup.c