From: James Morse james.morse@arm.com
commit 9fe0450785abbc04b0ed5d3cf61fcdb8ab656b4b upstream.
Resctrl assumes that all CPUs are online when the filesystem is mounted, and that CPUs remember their CDP-enabled state over CPU hotplug.
This goes wrong when resctrl's CDP-enabled state changes while all the CPUs in a domain are offline.
When a domain comes online, enable (or disable!) CDP to match resctrl's current setting.
Fixes: 5ff193fbde20 ("x86/intel_rdt: Add basic resctrl filesystem support") Suggested-by: Reinette Chatre reinette.chatre@intel.com Signed-off-by: James Morse james.morse@arm.com Signed-off-by: Borislav Petkov bp@suse.de Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20200221162105.154163-1-james.morse@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kernel/cpu/intel_rdt.c | 2 ++ arch/x86/kernel/cpu/intel_rdt.h | 1 + arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 13 +++++++++++++ 3 files changed, 16 insertions(+)
--- a/arch/x86/kernel/cpu/intel_rdt.c +++ b/arch/x86/kernel/cpu/intel_rdt.c @@ -555,6 +555,8 @@ static void domain_add_cpu(int cpu, stru d->id = id; cpumask_set_cpu(cpu, &d->cpu_mask);
+ rdt_domain_reconfigure_cdp(r); + if (r->alloc_capable && domain_setup_ctrlval(r, d)) { kfree(d); return; --- a/arch/x86/kernel/cpu/intel_rdt.h +++ b/arch/x86/kernel/cpu/intel_rdt.h @@ -567,5 +567,6 @@ void cqm_setup_limbo_handler(struct rdt_ void cqm_handle_limbo(struct work_struct *work); bool has_busy_rmid(struct rdt_resource *r, struct rdt_domain *d); void __check_limbo(struct rdt_domain *d, bool force_free); +void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
#endif /* _ASM_X86_INTEL_RDT_H */ --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c @@ -1777,6 +1777,19 @@ static int set_cache_qos_cfg(int level, return 0; }
+/* Restore the qos cfg state when a domain comes online */ +void rdt_domain_reconfigure_cdp(struct rdt_resource *r) +{ + if (!r->alloc_capable) + return; + + if (r == &rdt_resources_all[RDT_RESOURCE_L2DATA]) + l2_qos_cfg_update(&r->alloc_enabled); + + if (r == &rdt_resources_all[RDT_RESOURCE_L3DATA]) + l3_qos_cfg_update(&r->alloc_enabled); +} + /* * Enable or disable the MBA software controller * which helps user specify bandwidth in MBps.