arch/x86/xen/smp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/smp.h>
   3 #include <linux/cpu.h>
   4 #include <linux/slab.h>
   5 #include <linux/cpumask.h>
   6 #include <linux/percpu.h>
   7
   8 #include <xen/events.h>
   9
  10 #include <xen/hvc-console.h>
  11 #include "xen-ops.h"
  12 #include "smp.h"
  13
  14 static DEFINE_PER_CPU(struct xen_common_irq, xen_resched_irq) = { .irq = -1 };
  15 static DEFINE_PER_CPU(struct xen_common_irq, xen_callfunc_irq) = { .irq = -1 };
  16 static DEFINE_PER_CPU(struct xen_common_irq, xen_callfuncsingle_irq) = { .irq = -1 };
  17 static DEFINE_PER_CPU(struct xen_common_irq, xen_debug_irq) = { .irq = -1 };
  18
  19 static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id);
  20 static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id);
  21
  22 /*
  23  * Reschedule call back.
  24  */
  25 static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id)
  26 {
  27         inc_irq_stat(irq_resched_count);
  28         scheduler_ipi();
  29
  30         return IRQ_HANDLED;
  31 }
  32
  33 void xen_smp_intr_free(unsigned int cpu)
  34 {
  35         if (per_cpu(xen_resched_irq, cpu).irq >= 0) {
  36                 unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu).irq, NULL);
  37                 per_cpu(xen_resched_irq, cpu).irq = -1;
  38                 kfree(per_cpu(xen_resched_irq, cpu).name);
  39                 per_cpu(xen_resched_irq, cpu).name = NULL;
  40         }
  41         if (per_cpu(xen_callfunc_irq, cpu).irq >= 0) {
  42                 unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu).irq, NULL);
  43                 per_cpu(xen_callfunc_irq, cpu).irq = -1;
  44                 kfree(per_cpu(xen_callfunc_irq, cpu).name);
  45                 per_cpu(xen_callfunc_irq, cpu).name = NULL;
  46         }
  47         if (per_cpu(xen_debug_irq, cpu).irq >= 0) {
  48                 unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu).irq, NULL);
  49                 per_cpu(xen_debug_irq, cpu).irq = -1;
  50                 kfree(per_cpu(xen_debug_irq, cpu).name);
  51                 per_cpu(xen_debug_irq, cpu).name = NULL;
  52         }
  53         if (per_cpu(xen_callfuncsingle_irq, cpu).irq >= 0) {
  54                 unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu).irq,
  55                                        NULL);
  56                 per_cpu(xen_callfuncsingle_irq, cpu).irq = -1;
  57                 kfree(per_cpu(xen_callfuncsingle_irq, cpu).name);
  58                 per_cpu(xen_callfuncsingle_irq, cpu).name = NULL;
  59         }
  60 }
  61
  62 int xen_smp_intr_init(unsigned int cpu)
  63 {
  64         int rc;
  65         char *resched_name, *callfunc_name, *debug_name;
  66
  67         resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
  68         rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
  69                                     cpu,
  70                                     xen_reschedule_interrupt,
  71                                     IRQF_PERCPU|IRQF_NOBALANCING,
  72                                     resched_name,
  73                                     NULL);
  74         if (rc < 0)
  75                 goto fail;
  76         per_cpu(xen_resched_irq, cpu).irq = rc;
  77         per_cpu(xen_resched_irq, cpu).name = resched_name;
  78
  79         callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu);
  80         rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR,
  81                                     cpu,
  82                                     xen_call_function_interrupt,
  83                                     IRQF_PERCPU|IRQF_NOBALANCING,
  84                                     callfunc_name,
  85                                     NULL);
  86         if (rc < 0)
  87                 goto fail;
  88         per_cpu(xen_callfunc_irq, cpu).irq = rc;
  89         per_cpu(xen_callfunc_irq, cpu).name = callfunc_name;
  90
  91         debug_name = kasprintf(GFP_KERNEL, "debug%d", cpu);
  92         rc = bind_virq_to_irqhandler(VIRQ_DEBUG, cpu, xen_debug_interrupt,
  93                                      IRQF_PERCPU | IRQF_NOBALANCING,
  94                                      debug_name, NULL);
  95         if (rc < 0)
  96                 goto fail;
  97         per_cpu(xen_debug_irq, cpu).irq = rc;
  98         per_cpu(xen_debug_irq, cpu).name = debug_name;
  99
 100         callfunc_name = kasprintf(GFP_KERNEL, "callfuncsingle%d", cpu);
 101         rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR,
 102                                     cpu,
 103                                     xen_call_function_single_interrupt,
 104                                     IRQF_PERCPU|IRQF_NOBALANCING,
 105                                     callfunc_name,
 106                                     NULL);
 107         if (rc < 0)
 108                 goto fail;
 109         per_cpu(xen_callfuncsingle_irq, cpu).irq = rc;
 110         per_cpu(xen_callfuncsingle_irq, cpu).name = callfunc_name;
 111
 112         return 0;
 113
 114  fail:
 115         xen_smp_intr_free(cpu);
 116         return rc;
 117 }
 118
 119 void __init xen_smp_cpus_done(unsigned int max_cpus)
 120 {
 121         int cpu, rc, count = 0;
 122
 123         if (xen_hvm_domain())
 124                 native_smp_cpus_done(max_cpus);
 125
 126         if (xen_have_vcpu_info_placement)
 127                 return;
 128
 129         for_each_online_cpu(cpu) {
 130                 if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS)
 131                         continue;
 132
 133                 rc = cpu_down(cpu);
 134
 135                 if (rc == 0) {
 136                         /*
 137                          * Reset vcpu_info so this cpu cannot be onlined again.
 138                          */
 139                         xen_vcpu_info_reset(cpu);
 140                         count++;
 141                 } else {
 142                         pr_warn("%s: failed to bring CPU %d down, error %d\n",
 143                                 __func__, cpu, rc);
 144                 }
 145         }
 146         WARN(count, "%s: brought %d CPUs offline\n", __func__, count);
 147 }
 148
 149 void xen_smp_send_reschedule(int cpu)
 150 {
 151         xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
 152 }
 153
 154 static void __xen_send_IPI_mask(const struct cpumask *mask,
 155                               int vector)
 156 {
 157         unsigned cpu;
 158
 159         for_each_cpu_and(cpu, mask, cpu_online_mask)
 160                 xen_send_IPI_one(cpu, vector);
 161 }
 162
 163 void xen_smp_send_call_function_ipi(const struct cpumask *mask)
 164 {
 165         int cpu;
 166
 167         __xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);
 168
 169         /* Make sure other vcpus get a chance to run if they need to. */
 170         for_each_cpu(cpu, mask) {
 171                 if (xen_vcpu_stolen(cpu)) {
 172                         HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
 173                         break;
 174                 }
 175         }
 176 }
 177
 178 void xen_smp_send_call_function_single_ipi(int cpu)
 179 {
 180         __xen_send_IPI_mask(cpumask_of(cpu),
 181                           XEN_CALL_FUNCTION_SINGLE_VECTOR);
 182 }
 183
 184 static inline int xen_map_vector(int vector)
 185 {
 186         int xen_vector;
 187
 188         switch (vector) {
 189         case RESCHEDULE_VECTOR:
 190                 xen_vector = XEN_RESCHEDULE_VECTOR;
 191                 break;
 192         case CALL_FUNCTION_VECTOR:
 193                 xen_vector = XEN_CALL_FUNCTION_VECTOR;
 194                 break;
 195         case CALL_FUNCTION_SINGLE_VECTOR:
 196                 xen_vector = XEN_CALL_FUNCTION_SINGLE_VECTOR;
 197                 break;
 198         case IRQ_WORK_VECTOR:
 199                 xen_vector = XEN_IRQ_WORK_VECTOR;
 200                 break;
 201 #ifdef CONFIG_X86_64
 202         case NMI_VECTOR:
 203         case APIC_DM_NMI: /* Some use that instead of NMI_VECTOR */
 204                 xen_vector = XEN_NMI_VECTOR;
 205                 break;
 206 #endif
 207         default:
 208                 xen_vector = -1;
 209                 printk(KERN_ERR "xen: vector 0x%x is not implemented\n",
 210                         vector);
 211         }
 212
 213         return xen_vector;
 214 }
 215
 216 void xen_send_IPI_mask(const struct cpumask *mask,
 217                               int vector)
 218 {
 219         int xen_vector = xen_map_vector(vector);
 220
 221         if (xen_vector >= 0)
 222                 __xen_send_IPI_mask(mask, xen_vector);
 223 }
 224
 225 void xen_send_IPI_all(int vector)
 226 {
 227         int xen_vector = xen_map_vector(vector);
 228
 229         if (xen_vector >= 0)
 230                 __xen_send_IPI_mask(cpu_online_mask, xen_vector);
 231 }
 232
 233 void xen_send_IPI_self(int vector)
 234 {
 235         int xen_vector = xen_map_vector(vector);
 236
 237         if (xen_vector >= 0)
 238                 xen_send_IPI_one(smp_processor_id(), xen_vector);
 239 }
 240
 241 void xen_send_IPI_mask_allbutself(const struct cpumask *mask,
 242                                 int vector)
 243 {
 244         unsigned cpu;
 245         unsigned int this_cpu = smp_processor_id();
 246         int xen_vector = xen_map_vector(vector);
 247
 248         if (!(num_online_cpus() > 1) || (xen_vector < 0))
 249                 return;
 250
 251         for_each_cpu_and(cpu, mask, cpu_online_mask) {
 252                 if (this_cpu == cpu)
 253                         continue;
 254
 255                 xen_send_IPI_one(cpu, xen_vector);
 256         }
 257 }
 258
 259 void xen_send_IPI_allbutself(int vector)
 260 {
 261         xen_send_IPI_mask_allbutself(cpu_online_mask, vector);
 262 }
 263
 264 static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id)
 265 {
 266         irq_enter();
 267         generic_smp_call_function_interrupt();
 268         inc_irq_stat(irq_call_count);
 269         irq_exit();
 270
 271         return IRQ_HANDLED;
 272 }
 273
 274 static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id)
 275 {
 276         irq_enter();
 277         generic_smp_call_function_single_interrupt();
 278         inc_irq_stat(irq_call_count);
 279         irq_exit();
 280
 281         return IRQ_HANDLED;
 282 }