The checks to cpu_smt_control outside of kernel/cpu.c can be converted to use cpu_smt_enabled key to run SMT specific code.
Save the export of cpu_smt_control and convert usage of cpu_smt_control to cpu_smt_enabled outside of kernel/cpu.c.
Signed-off-by: Tim Chen tim.c.chen@linux.intel.com --- arch/x86/kernel/cpu/bugs.c | 13 +++++++------ arch/x86/kvm/vmx.c | 2 +- include/linux/cpu.h | 12 +++--------- kernel/cpu.c | 11 +++++++++-- 4 files changed, 20 insertions(+), 18 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index a63456a..3e5ae2c 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -353,15 +353,16 @@ void arch_smt_update(void)
mutex_lock(&spec_ctrl_mutex); mask = x86_spec_ctrl_base; - if (cpu_smt_control == CPU_SMT_ENABLED) + if (cpu_use_smt_and_hotplug) mask |= SPEC_CTRL_STIBP; else mask &= ~SPEC_CTRL_STIBP;
if (mask != x86_spec_ctrl_base) { - pr_info("Spectre v2 cross-process SMT mitigation: %s STIBP\n", - cpu_smt_control == CPU_SMT_ENABLED ? - "Enabling" : "Disabling"); + if (cpu_use_smt_and_hotplug) + pr_info("Spectre v2 cross-process SMT mitigation: Enabling STIBP\n"); + else + pr_info("Spectre v2 cross-process SMT mitigation: Disabling STIBP\n"); x86_spec_ctrl_base = mask; on_each_cpu(update_stibp_msr, NULL, 1); } @@ -844,13 +845,13 @@ static ssize_t l1tf_show_state(char *buf)
if (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_EPT_DISABLED || (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_NEVER && - cpu_smt_control == CPU_SMT_ENABLED)) + cpu_use_smt_and_hotplug)) return sprintf(buf, "%s; VMX: %s\n", L1TF_DEFAULT_MSG, l1tf_vmx_states[l1tf_vmx_mitigation]);
return sprintf(buf, "%s; VMX: %s, SMT %s\n", L1TF_DEFAULT_MSG, l1tf_vmx_states[l1tf_vmx_mitigation], - cpu_smt_control == CPU_SMT_ENABLED ? "vulnerable" : "disabled"); + cpu_use_smt_and_hotplug ? "vulnerable" : "disabled"); } #else static ssize_t l1tf_show_state(char *buf) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 4555077..6c71d4c 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -11607,7 +11607,7 @@ static int vmx_vm_init(struct kvm *kvm) * Warn upon starting the first VM in a potentially * insecure environment. */ - if (cpu_smt_control == CPU_SMT_ENABLED) + if (cpu_use_smt_and_hotplug) pr_warn_once(L1TF_MSG_SMT); if (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_NEVER) pr_warn_once(L1TF_MSG_L1D); diff --git a/include/linux/cpu.h b/include/linux/cpu.h index ce8267e..6f43024 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -170,20 +170,14 @@ void cpuhp_report_idle_dead(void); static inline void cpuhp_report_idle_dead(void) { } #endif /* #ifdef CONFIG_HOTPLUG_CPU */
-enum cpuhp_smt_control { - CPU_SMT_ENABLED, - CPU_SMT_DISABLED, - CPU_SMT_FORCE_DISABLED, - CPU_SMT_NOT_SUPPORTED, -}; - #if defined(CONFIG_SMP) && defined(CONFIG_HOTPLUG_SMT) -extern enum cpuhp_smt_control cpu_smt_control; +DECLARE_STATIC_KEY_TRUE(cpu_smt_enabled); +#define cpu_use_smt_and_hotplug (static_branch_likely(&cpu_smt_enabled)) extern void cpu_smt_disable(bool force); extern void cpu_smt_check_topology_early(void); extern void cpu_smt_check_topology(void); #else -# define cpu_smt_control (CPU_SMT_ENABLED) +#define cpu_use_smt_and_hotplug false static inline void cpu_smt_disable(bool force) { } static inline void cpu_smt_check_topology_early(void) { } static inline void cpu_smt_check_topology(void) { } diff --git a/kernel/cpu.c b/kernel/cpu.c index e216154..f846416 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -368,8 +368,15 @@ static void lockdep_release_cpus_lock(void) #endif /* CONFIG_HOTPLUG_CPU */
#ifdef CONFIG_HOTPLUG_SMT -enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; -EXPORT_SYMBOL_GPL(cpu_smt_control); + +enum cpuhp_smt_control { + CPU_SMT_ENABLED, + CPU_SMT_DISABLED, + CPU_SMT_FORCE_DISABLED, + CPU_SMT_NOT_SUPPORTED, +}; + +static enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; DEFINE_STATIC_KEY_TRUE(cpu_smt_enabled); EXPORT_SYMBOL_GPL(cpu_smt_enabled);