diff options
Diffstat (limited to 'arch/powerpc/platforms/pseries/smp.c')
| -rw-r--r-- | arch/powerpc/platforms/pseries/smp.c | 90 |
1 files changed, 45 insertions, 45 deletions
diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c index 6891710833be..92922491a81c 100644 --- a/arch/powerpc/platforms/pseries/smp.c +++ b/arch/powerpc/platforms/pseries/smp.c @@ -44,8 +44,6 @@ #include <asm/svm.h> #include "pseries.h" -#include "offline_states.h" - /* * The Primary thread of each non-boot processor was started from the OF client @@ -108,10 +106,7 @@ static inline int smp_startup_cpu(unsigned int lcpu) /* Fixup atomic count: it exited inside IRQ handler. */ task_thread_info(paca_ptrs[lcpu]->__current)->preempt_count = 0; -#ifdef CONFIG_HOTPLUG_CPU - if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE) - goto out; -#endif + /* * If the RTAS start-cpu token does not exist then presume the * cpu is already spinning. @@ -126,9 +121,6 @@ static inline int smp_startup_cpu(unsigned int lcpu) return 0; } -#ifdef CONFIG_HOTPLUG_CPU -out: -#endif return 1; } @@ -143,10 +135,6 @@ static void smp_setup_cpu(int cpu) vpa_init(cpu); cpumask_clear_cpu(cpu, of_spin_mask); -#ifdef CONFIG_HOTPLUG_CPU - set_cpu_current_state(cpu, CPU_STATE_ONLINE); - set_default_offline_state(cpu); -#endif } static int smp_pSeries_kick_cpu(int nr) @@ -163,20 +151,6 @@ static int smp_pSeries_kick_cpu(int nr) * the processor will continue on to secondary_start */ paca_ptrs[nr]->cpu_start = 1; -#ifdef CONFIG_HOTPLUG_CPU - set_preferred_offline_state(nr, CPU_STATE_ONLINE); - - if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) { - long rc; - unsigned long hcpuid; - - hcpuid = get_hard_smp_processor_id(nr); - rc = plpar_hcall_norets(H_PROD, hcpuid); - if (rc != H_SUCCESS) - printk(KERN_ERR "Error: Prod to wake up processor %d " - "Ret= %ld\n", nr, rc); - } -#endif return 0; } @@ -188,13 +162,16 @@ static int pseries_smp_prepare_cpu(int cpu) return 0; } -static void smp_pseries_cause_ipi(int cpu) +/* Cause IPI as setup by the interrupt controller (xics or xive) */ +static void (*ic_cause_ipi)(int cpu) __ro_after_init; + +/* Use msgsndp doorbells target is a sibling, else use interrupt controller */ +static void dbell_or_ic_cause_ipi(int cpu) { - /* POWER9 should not use this handler */ if (doorbell_try_core_ipi(cpu)) return; - icp_ops->cause_ipi(cpu); + ic_cause_ipi(cpu); } static int pseries_cause_nmi_ipi(int cpu) @@ -218,26 +195,49 @@ static int pseries_cause_nmi_ipi(int cpu) return 0; } -static __init void pSeries_smp_probe_xics(void) -{ - xics_smp_probe(); - - if (cpu_has_feature(CPU_FTR_DBELL) && !is_secure_guest()) - smp_ops->cause_ipi = smp_pseries_cause_ipi; - else - smp_ops->cause_ipi = icp_ops->cause_ipi; -} - static __init void pSeries_smp_probe(void) { if (xive_enabled()) - /* - * Don't use P9 doorbells when XIVE is enabled. IPIs - * using MMIOs should be faster - */ xive_smp_probe(); else - pSeries_smp_probe_xics(); + xics_smp_probe(); + + /* No doorbell facility, must use the interrupt controller for IPIs */ + if (!cpu_has_feature(CPU_FTR_DBELL)) + return; + + /* Doorbells can only be used for IPIs between SMT siblings */ + if (!cpu_has_feature(CPU_FTR_SMT)) + return; + + if (is_kvm_guest()) { + /* + * KVM emulates doorbells by disabling FSCR[MSGP] so msgsndp + * faults to the hypervisor which then reads the instruction + * from guest memory, which tends to be slower than using XIVE. + */ + if (xive_enabled()) + return; + + /* + * XICS hcalls aren't as fast, so we can use msgsndp (which + * also helps exercise KVM emulation), however KVM can't + * emulate secure guests because it can't read the instruction + * out of their memory. + */ + if (is_secure_guest()) + return; + } + + /* + * Under PowerVM, FSCR[MSGP] is enabled as guest vCPU siblings are + * gang scheduled on the same physical core, so doorbells are always + * faster than the interrupt controller, and they can be used by + * secure guests. + */ + + ic_cause_ipi = smp_ops->cause_ipi; + smp_ops->cause_ipi = dbell_or_ic_cause_ipi; } static struct smp_ops_t pseries_smp_ops = { |