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

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 83e40341583e6fa655e0531f0e8a8480d8567ba8..acf52aa185e091d62e26bc81a01dd65cc5e276db 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -362,6 +362,8 @@ struct rdt_domain *get_domain_from_cpu(int cpu, struct rdt_resource *r)
 {
        struct rdt_domain *d;
 
+       lockdep_assert_cpus_held();
+
        list_for_each_entry(d, &r->domains, list) {
                /* Find the domain that contains this CPU */
                if (cpumask_test_cpu(cpu, &d->cpu_mask))
@@ -378,19 +380,11 @@ u32 resctrl_arch_get_num_closid(struct rdt_resource *r)
 
 void rdt_ctrl_update(void *arg)
 {
+       struct rdt_hw_resource *hw_res;
        struct msr_param *m = arg;
-       struct rdt_hw_resource *hw_res = resctrl_to_arch_res(m->res);
-       struct rdt_resource *r = m->res;
-       int cpu = smp_processor_id();
-       struct rdt_domain *d;
 
-       d = get_domain_from_cpu(cpu, r);
-       if (d) {
-               hw_res->msr_update(d, m, r);
-               return;
-       }
-       pr_warn_once("cpu %d not found in any domain for resource %s\n",
-                    cpu, r->name);
+       hw_res = resctrl_to_arch_res(m->res);
+       hw_res->msr_update(m->dom, m, m->res);
 }
 
 /*
@@ -463,6 +457,7 @@ static int domain_setup_ctrlval(struct rdt_resource *r, struct rdt_domain *d)
        hw_dom->ctrl_val = dc;
        setup_default_ctrlval(r, dc);
 
+       m.dom = d;
        m.low = 0;
        m.high = hw_res->num_closid;
        hw_res->msr_update(d, &m, r);

diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 7997b47743a210d6d437976bb53d667d0df92f21..165d8d453c04189a1d975080bc451e514756663b 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -272,22 +272,6 @@ static u32 get_config_index(u32 closid, enum resctrl_conf_type type)
        }
 }
 
-static bool apply_config(struct rdt_hw_domain *hw_dom,
-                        struct resctrl_staged_config *cfg, u32 idx,
-                        cpumask_var_t cpu_mask)
-{
-       struct rdt_domain *dom = &hw_dom->d_resctrl;
-
-       if (cfg->new_ctrl != hw_dom->ctrl_val[idx]) {
-               cpumask_set_cpu(cpumask_any(&dom->cpu_mask), cpu_mask);
-               hw_dom->ctrl_val[idx] = cfg->new_ctrl;
-
-               return true;
-       }
-
-       return false;
-}
-
 int resctrl_arch_update_one(struct rdt_resource *r, struct rdt_domain *d,
                            u32 closid, enum resctrl_conf_type t, u32 cfg_val)
 {
@@ -302,6 +286,7 @@ int resctrl_arch_update_one(struct rdt_resource *r, struct rdt_domain *d,
        hw_dom->ctrl_val[idx] = cfg_val;
 
        msr_param.res = r;
+       msr_param.dom = d;
        msr_param.low = idx;
        msr_param.high = idx + 1;
        hw_res->msr_update(d, &msr_param, r);
@@ -315,48 +300,39 @@ int resctrl_arch_update_domains(struct rdt_resource *r, u32 closid)
        struct rdt_hw_domain *hw_dom;
        struct msr_param msr_param;
        enum resctrl_conf_type t;
-       cpumask_var_t cpu_mask;
        struct rdt_domain *d;
        u32 idx;
 
        /* Walking r->domains, ensure it can't race with cpuhp */
        lockdep_assert_cpus_held();
 
-       if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
-               return -ENOMEM;
-
-       msr_param.res = NULL;
        list_for_each_entry(d, &r->domains, list) {
                hw_dom = resctrl_to_arch_dom(d);
+               msr_param.res = NULL;
                for (t = 0; t < CDP_NUM_TYPES; t++) {
                        cfg = &hw_dom->d_resctrl.staged_config[t];
                        if (!cfg->have_new_ctrl)
                                continue;
 
                        idx = get_config_index(closid, t);
-                       if (!apply_config(hw_dom, cfg, idx, cpu_mask))
+                       if (cfg->new_ctrl == hw_dom->ctrl_val[idx])
                                continue;
+                       hw_dom->ctrl_val[idx] = cfg->new_ctrl;
 
                        if (!msr_param.res) {
                                msr_param.low = idx;
                                msr_param.high = msr_param.low + 1;
                                msr_param.res = r;
+                               msr_param.dom = d;
                        } else {
                                msr_param.low = min(msr_param.low, idx);
                                msr_param.high = max(msr_param.high, idx + 1);
                        }
                }
+               if (msr_param.res)
+                       smp_call_function_any(&d->cpu_mask, rdt_ctrl_update, &msr_param, 1);
        }
 
-       if (cpumask_empty(cpu_mask))
-               goto done;
-
-       /* Update resource control msr on all the CPUs. */
-       on_each_cpu_mask(cpu_mask, rdt_ctrl_update, &msr_param, 1);
-
-done:
-       free_cpumask_var(cpu_mask);
-
        return 0;
 }
 

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 1a8687f8073a89f3335038c8b3ba7e2ee45aa6d4..ab2d315f7a2e8117bc5f7af4f11fe8009f4c9a76 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -379,11 +379,13 @@ static inline struct rdt_hw_domain *resctrl_to_arch_dom(struct rdt_domain *r)
 /**
  * struct msr_param - set a range of MSRs from a domain
  * @res:       The resource to use
+ * @dom:       The domain to update
  * @low:       Beginning index from base MSR
  * @high:      End index
  */
 struct msr_param {
        struct rdt_resource     *res;
+       struct rdt_domain       *dom;
        u32                     low;
        u32                     high;
 };

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 011e17efb1a66e5b003fee07b53c13633f9f0f58..02f213f1c51c5158c6c2cf540ab7e0e351b0bf49 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2813,16 +2813,12 @@ static int reset_all_ctrls(struct rdt_resource *r)
        struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
        struct rdt_hw_domain *hw_dom;
        struct msr_param msr_param;
-       cpumask_var_t cpu_mask;
        struct rdt_domain *d;
        int i;
 
        /* Walking r->domains, ensure it can't race with cpuhp */
        lockdep_assert_cpus_held();
 
-       if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
-               return -ENOMEM;
-
        msr_param.res = r;
        msr_param.low = 0;
        msr_param.high = hw_res->num_closid;
@@ -2834,17 +2830,13 @@ static int reset_all_ctrls(struct rdt_resource *r)
         */
        list_for_each_entry(d, &r->domains, list) {
                hw_dom = resctrl_to_arch_dom(d);
-               cpumask_set_cpu(cpumask_any(&d->cpu_mask), cpu_mask);
 
                for (i = 0; i < hw_res->num_closid; i++)
                        hw_dom->ctrl_val[i] = r->default_ctrl;
+               msr_param.dom = d;
+               smp_call_function_any(&d->cpu_mask, rdt_ctrl_update, &msr_param, 1);
        }
 
-       /* Update CBM on all the CPUs in cpu_mask */
-       on_each_cpu_mask(cpu_mask, rdt_ctrl_update, &msr_param, 1);
-
-       free_cpumask_var(cpu_mask);
-
        return 0;
 }