David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Xen event channels (2-level ABI) |
| 3 | * |
| 4 | * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 |
| 5 | */ |
| 6 | |
| 7 | #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt |
| 8 | |
| 9 | #include <linux/linkage.h> |
| 10 | #include <linux/interrupt.h> |
| 11 | #include <linux/irq.h> |
| 12 | #include <linux/module.h> |
| 13 | |
| 14 | #include <asm/sync_bitops.h> |
| 15 | #include <asm/xen/hypercall.h> |
| 16 | #include <asm/xen/hypervisor.h> |
| 17 | |
| 18 | #include <xen/xen.h> |
| 19 | #include <xen/xen-ops.h> |
| 20 | #include <xen/events.h> |
| 21 | #include <xen/interface/xen.h> |
| 22 | #include <xen/interface/event_channel.h> |
| 23 | |
| 24 | #include "events_internal.h" |
| 25 | |
| 26 | /* |
| 27 | * Note sizeof(xen_ulong_t) can be more than sizeof(unsigned long). Be |
| 28 | * careful to only use bitops which allow for this (e.g |
| 29 | * test_bit/find_first_bit and friends but not __ffs) and to pass |
| 30 | * BITS_PER_EVTCHN_WORD as the bitmask length. |
| 31 | */ |
| 32 | #define BITS_PER_EVTCHN_WORD (sizeof(xen_ulong_t)*8) |
| 33 | /* |
| 34 | * Make a bitmask (i.e. unsigned long *) of a xen_ulong_t |
| 35 | * array. Primarily to avoid long lines (hence the terse name). |
| 36 | */ |
| 37 | #define BM(x) (unsigned long *)(x) |
| 38 | /* Find the first set bit in a evtchn mask */ |
| 39 | #define EVTCHN_FIRST_BIT(w) find_first_bit(BM(&(w)), BITS_PER_EVTCHN_WORD) |
| 40 | |
David Vrabel | bf2bbe0 | 2013-03-15 10:55:41 +0000 | [diff] [blame] | 41 | static DEFINE_PER_CPU(xen_ulong_t [EVTCHN_2L_NR_CHANNELS/BITS_PER_EVTCHN_WORD], |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 42 | cpu_evtchn_mask); |
| 43 | |
David Vrabel | d0b075f | 2013-10-17 15:23:15 +0100 | [diff] [blame] | 44 | static unsigned evtchn_2l_max_channels(void) |
| 45 | { |
David Vrabel | bf2bbe0 | 2013-03-15 10:55:41 +0000 | [diff] [blame] | 46 | return EVTCHN_2L_NR_CHANNELS; |
David Vrabel | d0b075f | 2013-10-17 15:23:15 +0100 | [diff] [blame] | 47 | } |
| 48 | |
David Vrabel | ab9a1cc | 2013-03-14 12:49:19 +0000 | [diff] [blame] | 49 | static void evtchn_2l_bind_to_cpu(struct irq_info *info, unsigned cpu) |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 50 | { |
| 51 | clear_bit(info->evtchn, BM(per_cpu(cpu_evtchn_mask, info->cpu))); |
| 52 | set_bit(info->evtchn, BM(per_cpu(cpu_evtchn_mask, cpu))); |
| 53 | } |
| 54 | |
David Vrabel | ab9a1cc | 2013-03-14 12:49:19 +0000 | [diff] [blame] | 55 | static void evtchn_2l_clear_pending(unsigned port) |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 56 | { |
| 57 | struct shared_info *s = HYPERVISOR_shared_info; |
| 58 | sync_clear_bit(port, BM(&s->evtchn_pending[0])); |
| 59 | } |
| 60 | |
David Vrabel | ab9a1cc | 2013-03-14 12:49:19 +0000 | [diff] [blame] | 61 | static void evtchn_2l_set_pending(unsigned port) |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 62 | { |
| 63 | struct shared_info *s = HYPERVISOR_shared_info; |
| 64 | sync_set_bit(port, BM(&s->evtchn_pending[0])); |
| 65 | } |
| 66 | |
David Vrabel | ab9a1cc | 2013-03-14 12:49:19 +0000 | [diff] [blame] | 67 | static bool evtchn_2l_is_pending(unsigned port) |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 68 | { |
| 69 | struct shared_info *s = HYPERVISOR_shared_info; |
| 70 | return sync_test_bit(port, BM(&s->evtchn_pending[0])); |
| 71 | } |
| 72 | |
David Vrabel | ab9a1cc | 2013-03-14 12:49:19 +0000 | [diff] [blame] | 73 | static bool evtchn_2l_test_and_set_mask(unsigned port) |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 74 | { |
| 75 | struct shared_info *s = HYPERVISOR_shared_info; |
| 76 | return sync_test_and_set_bit(port, BM(&s->evtchn_mask[0])); |
| 77 | } |
| 78 | |
David Vrabel | ab9a1cc | 2013-03-14 12:49:19 +0000 | [diff] [blame] | 79 | static void evtchn_2l_mask(unsigned port) |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 80 | { |
| 81 | struct shared_info *s = HYPERVISOR_shared_info; |
| 82 | sync_set_bit(port, BM(&s->evtchn_mask[0])); |
| 83 | } |
| 84 | |
David Vrabel | ab9a1cc | 2013-03-14 12:49:19 +0000 | [diff] [blame] | 85 | static void evtchn_2l_unmask(unsigned port) |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 86 | { |
| 87 | struct shared_info *s = HYPERVISOR_shared_info; |
| 88 | unsigned int cpu = get_cpu(); |
| 89 | int do_hypercall = 0, evtchn_pending = 0; |
| 90 | |
| 91 | BUG_ON(!irqs_disabled()); |
| 92 | |
| 93 | if (unlikely((cpu != cpu_from_evtchn(port)))) |
| 94 | do_hypercall = 1; |
| 95 | else { |
| 96 | /* |
| 97 | * Need to clear the mask before checking pending to |
| 98 | * avoid a race with an event becoming pending. |
| 99 | * |
| 100 | * EVTCHNOP_unmask will only trigger an upcall if the |
| 101 | * mask bit was set, so if a hypercall is needed |
| 102 | * remask the event. |
| 103 | */ |
| 104 | sync_clear_bit(port, BM(&s->evtchn_mask[0])); |
| 105 | evtchn_pending = sync_test_bit(port, BM(&s->evtchn_pending[0])); |
| 106 | |
| 107 | if (unlikely(evtchn_pending && xen_hvm_domain())) { |
| 108 | sync_set_bit(port, BM(&s->evtchn_mask[0])); |
| 109 | do_hypercall = 1; |
| 110 | } |
| 111 | } |
| 112 | |
| 113 | /* Slow path (hypercall) if this is a non-local port or if this is |
| 114 | * an hvm domain and an event is pending (hvm domains don't have |
| 115 | * their own implementation of irq_enable). */ |
| 116 | if (do_hypercall) { |
| 117 | struct evtchn_unmask unmask = { .port = port }; |
| 118 | (void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask); |
| 119 | } else { |
| 120 | struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu); |
| 121 | |
| 122 | /* |
| 123 | * The following is basically the equivalent of |
| 124 | * 'hw_resend_irq'. Just like a real IO-APIC we 'lose |
| 125 | * the interrupt edge' if the channel is masked. |
| 126 | */ |
| 127 | if (evtchn_pending && |
| 128 | !sync_test_and_set_bit(port / BITS_PER_EVTCHN_WORD, |
| 129 | BM(&vcpu_info->evtchn_pending_sel))) |
| 130 | vcpu_info->evtchn_upcall_pending = 1; |
| 131 | } |
| 132 | |
| 133 | put_cpu(); |
| 134 | } |
| 135 | |
| 136 | static DEFINE_PER_CPU(unsigned int, current_word_idx); |
| 137 | static DEFINE_PER_CPU(unsigned int, current_bit_idx); |
| 138 | |
| 139 | /* |
| 140 | * Mask out the i least significant bits of w |
| 141 | */ |
| 142 | #define MASK_LSBS(w, i) (w & ((~((xen_ulong_t)0UL)) << i)) |
| 143 | |
| 144 | static inline xen_ulong_t active_evtchns(unsigned int cpu, |
| 145 | struct shared_info *sh, |
| 146 | unsigned int idx) |
| 147 | { |
| 148 | return sh->evtchn_pending[idx] & |
| 149 | per_cpu(cpu_evtchn_mask, cpu)[idx] & |
| 150 | ~sh->evtchn_mask[idx]; |
| 151 | } |
| 152 | |
| 153 | /* |
| 154 | * Search the CPU's pending events bitmasks. For each one found, map |
| 155 | * the event number to an irq, and feed it into do_IRQ() for handling. |
| 156 | * |
| 157 | * Xen uses a two-level bitmap to speed searching. The first level is |
| 158 | * a bitset of words which contain pending event bits. The second |
| 159 | * level is a bitset of pending events themselves. |
| 160 | */ |
David Vrabel | ab9a1cc | 2013-03-14 12:49:19 +0000 | [diff] [blame] | 161 | static void evtchn_2l_handle_events(unsigned cpu) |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 162 | { |
| 163 | int irq; |
| 164 | xen_ulong_t pending_words; |
| 165 | xen_ulong_t pending_bits; |
| 166 | int start_word_idx, start_bit_idx; |
| 167 | int word_idx, bit_idx; |
| 168 | int i; |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 169 | struct shared_info *s = HYPERVISOR_shared_info; |
| 170 | struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu); |
| 171 | |
| 172 | /* Timer interrupt has highest priority. */ |
| 173 | irq = irq_from_virq(cpu, VIRQ_TIMER); |
| 174 | if (irq != -1) { |
| 175 | unsigned int evtchn = evtchn_from_irq(irq); |
| 176 | word_idx = evtchn / BITS_PER_LONG; |
| 177 | bit_idx = evtchn % BITS_PER_LONG; |
Thomas Gleixner | 589d03e | 2014-02-23 21:40:18 +0000 | [diff] [blame] | 178 | if (active_evtchns(cpu, s, word_idx) & (1ULL << bit_idx)) |
| 179 | generic_handle_irq(irq); |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 180 | } |
| 181 | |
| 182 | /* |
| 183 | * Master flag must be cleared /before/ clearing |
| 184 | * selector flag. xchg_xen_ulong must contain an |
| 185 | * appropriate barrier. |
| 186 | */ |
| 187 | pending_words = xchg_xen_ulong(&vcpu_info->evtchn_pending_sel, 0); |
| 188 | |
| 189 | start_word_idx = __this_cpu_read(current_word_idx); |
| 190 | start_bit_idx = __this_cpu_read(current_bit_idx); |
| 191 | |
| 192 | word_idx = start_word_idx; |
| 193 | |
| 194 | for (i = 0; pending_words != 0; i++) { |
| 195 | xen_ulong_t words; |
| 196 | |
| 197 | words = MASK_LSBS(pending_words, word_idx); |
| 198 | |
| 199 | /* |
| 200 | * If we masked out all events, wrap to beginning. |
| 201 | */ |
| 202 | if (words == 0) { |
| 203 | word_idx = 0; |
| 204 | bit_idx = 0; |
| 205 | continue; |
| 206 | } |
| 207 | word_idx = EVTCHN_FIRST_BIT(words); |
| 208 | |
| 209 | pending_bits = active_evtchns(cpu, s, word_idx); |
| 210 | bit_idx = 0; /* usually scan entire word from start */ |
| 211 | /* |
| 212 | * We scan the starting word in two parts. |
| 213 | * |
| 214 | * 1st time: start in the middle, scanning the |
| 215 | * upper bits. |
| 216 | * |
| 217 | * 2nd time: scan the whole word (not just the |
| 218 | * parts skipped in the first pass) -- if an |
| 219 | * event in the previously scanned bits is |
| 220 | * pending again it would just be scanned on |
| 221 | * the next loop anyway. |
| 222 | */ |
| 223 | if (word_idx == start_word_idx) { |
| 224 | if (i == 0) |
| 225 | bit_idx = start_bit_idx; |
| 226 | } |
| 227 | |
| 228 | do { |
| 229 | xen_ulong_t bits; |
| 230 | int port; |
| 231 | |
| 232 | bits = MASK_LSBS(pending_bits, bit_idx); |
| 233 | |
| 234 | /* If we masked out all events, move on. */ |
| 235 | if (bits == 0) |
| 236 | break; |
| 237 | |
| 238 | bit_idx = EVTCHN_FIRST_BIT(bits); |
| 239 | |
| 240 | /* Process port. */ |
| 241 | port = (word_idx * BITS_PER_EVTCHN_WORD) + bit_idx; |
David Vrabel | d0b075f | 2013-10-17 15:23:15 +0100 | [diff] [blame] | 242 | irq = get_evtchn_to_irq(port); |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 243 | |
Thomas Gleixner | 589d03e | 2014-02-23 21:40:18 +0000 | [diff] [blame] | 244 | if (irq != -1) |
| 245 | generic_handle_irq(irq); |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 246 | |
| 247 | bit_idx = (bit_idx + 1) % BITS_PER_EVTCHN_WORD; |
| 248 | |
| 249 | /* Next caller starts at last processed + 1 */ |
| 250 | __this_cpu_write(current_word_idx, |
| 251 | bit_idx ? word_idx : |
| 252 | (word_idx+1) % BITS_PER_EVTCHN_WORD); |
| 253 | __this_cpu_write(current_bit_idx, bit_idx); |
| 254 | } while (bit_idx != 0); |
| 255 | |
| 256 | /* Scan start_l1i twice; all others once. */ |
| 257 | if ((word_idx != start_word_idx) || (i != 0)) |
| 258 | pending_words &= ~(1UL << word_idx); |
| 259 | |
| 260 | word_idx = (word_idx + 1) % BITS_PER_EVTCHN_WORD; |
| 261 | } |
| 262 | } |
| 263 | |
| 264 | irqreturn_t xen_debug_interrupt(int irq, void *dev_id) |
| 265 | { |
| 266 | struct shared_info *sh = HYPERVISOR_shared_info; |
| 267 | int cpu = smp_processor_id(); |
| 268 | xen_ulong_t *cpu_evtchn = per_cpu(cpu_evtchn_mask, cpu); |
| 269 | int i; |
| 270 | unsigned long flags; |
| 271 | static DEFINE_SPINLOCK(debug_lock); |
| 272 | struct vcpu_info *v; |
| 273 | |
| 274 | spin_lock_irqsave(&debug_lock, flags); |
| 275 | |
| 276 | printk("\nvcpu %d\n ", cpu); |
| 277 | |
| 278 | for_each_online_cpu(i) { |
| 279 | int pending; |
| 280 | v = per_cpu(xen_vcpu, i); |
| 281 | pending = (get_irq_regs() && i == cpu) |
| 282 | ? xen_irqs_disabled(get_irq_regs()) |
| 283 | : v->evtchn_upcall_mask; |
| 284 | printk("%d: masked=%d pending=%d event_sel %0*"PRI_xen_ulong"\n ", i, |
| 285 | pending, v->evtchn_upcall_pending, |
| 286 | (int)(sizeof(v->evtchn_pending_sel)*2), |
| 287 | v->evtchn_pending_sel); |
| 288 | } |
| 289 | v = per_cpu(xen_vcpu, cpu); |
| 290 | |
| 291 | printk("\npending:\n "); |
| 292 | for (i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--) |
| 293 | printk("%0*"PRI_xen_ulong"%s", |
| 294 | (int)sizeof(sh->evtchn_pending[0])*2, |
| 295 | sh->evtchn_pending[i], |
| 296 | i % 8 == 0 ? "\n " : " "); |
| 297 | printk("\nglobal mask:\n "); |
| 298 | for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--) |
| 299 | printk("%0*"PRI_xen_ulong"%s", |
| 300 | (int)(sizeof(sh->evtchn_mask[0])*2), |
| 301 | sh->evtchn_mask[i], |
| 302 | i % 8 == 0 ? "\n " : " "); |
| 303 | |
| 304 | printk("\nglobally unmasked:\n "); |
| 305 | for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--) |
| 306 | printk("%0*"PRI_xen_ulong"%s", |
| 307 | (int)(sizeof(sh->evtchn_mask[0])*2), |
| 308 | sh->evtchn_pending[i] & ~sh->evtchn_mask[i], |
| 309 | i % 8 == 0 ? "\n " : " "); |
| 310 | |
| 311 | printk("\nlocal cpu%d mask:\n ", cpu); |
David Vrabel | bf2bbe0 | 2013-03-15 10:55:41 +0000 | [diff] [blame] | 312 | for (i = (EVTCHN_2L_NR_CHANNELS/BITS_PER_EVTCHN_WORD)-1; i >= 0; i--) |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 313 | printk("%0*"PRI_xen_ulong"%s", (int)(sizeof(cpu_evtchn[0])*2), |
| 314 | cpu_evtchn[i], |
| 315 | i % 8 == 0 ? "\n " : " "); |
| 316 | |
| 317 | printk("\nlocally unmasked:\n "); |
| 318 | for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--) { |
| 319 | xen_ulong_t pending = sh->evtchn_pending[i] |
| 320 | & ~sh->evtchn_mask[i] |
| 321 | & cpu_evtchn[i]; |
| 322 | printk("%0*"PRI_xen_ulong"%s", |
| 323 | (int)(sizeof(sh->evtchn_mask[0])*2), |
| 324 | pending, i % 8 == 0 ? "\n " : " "); |
| 325 | } |
| 326 | |
| 327 | printk("\npending list:\n"); |
David Vrabel | bf2bbe0 | 2013-03-15 10:55:41 +0000 | [diff] [blame] | 328 | for (i = 0; i < EVTCHN_2L_NR_CHANNELS; i++) { |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 329 | if (sync_test_bit(i, BM(sh->evtchn_pending))) { |
| 330 | int word_idx = i / BITS_PER_EVTCHN_WORD; |
| 331 | printk(" %d: event %d -> irq %d%s%s%s\n", |
| 332 | cpu_from_evtchn(i), i, |
David Vrabel | d0b075f | 2013-10-17 15:23:15 +0100 | [diff] [blame] | 333 | get_evtchn_to_irq(i), |
David Vrabel | 9a489f4 | 2013-03-13 15:29:25 +0000 | [diff] [blame] | 334 | sync_test_bit(word_idx, BM(&v->evtchn_pending_sel)) |
| 335 | ? "" : " l2-clear", |
| 336 | !sync_test_bit(i, BM(sh->evtchn_mask)) |
| 337 | ? "" : " globally-masked", |
| 338 | sync_test_bit(i, BM(cpu_evtchn)) |
| 339 | ? "" : " locally-masked"); |
| 340 | } |
| 341 | } |
| 342 | |
| 343 | spin_unlock_irqrestore(&debug_lock, flags); |
| 344 | |
| 345 | return IRQ_HANDLED; |
| 346 | } |
David Vrabel | ab9a1cc | 2013-03-14 12:49:19 +0000 | [diff] [blame] | 347 | |
Boris Ostrovsky | 5cec988 | 2015-04-29 17:10:12 -0400 | [diff] [blame] | 348 | static void evtchn_2l_resume(void) |
| 349 | { |
| 350 | int i; |
| 351 | |
| 352 | for_each_online_cpu(i) |
| 353 | memset(per_cpu(cpu_evtchn_mask, i), 0, sizeof(xen_ulong_t) * |
| 354 | EVTCHN_2L_NR_CHANNELS/BITS_PER_EVTCHN_WORD); |
| 355 | } |
| 356 | |
David Vrabel | ab9a1cc | 2013-03-14 12:49:19 +0000 | [diff] [blame] | 357 | static const struct evtchn_ops evtchn_ops_2l = { |
David Vrabel | d0b075f | 2013-10-17 15:23:15 +0100 | [diff] [blame] | 358 | .max_channels = evtchn_2l_max_channels, |
| 359 | .nr_channels = evtchn_2l_max_channels, |
David Vrabel | ab9a1cc | 2013-03-14 12:49:19 +0000 | [diff] [blame] | 360 | .bind_to_cpu = evtchn_2l_bind_to_cpu, |
| 361 | .clear_pending = evtchn_2l_clear_pending, |
| 362 | .set_pending = evtchn_2l_set_pending, |
| 363 | .is_pending = evtchn_2l_is_pending, |
| 364 | .test_and_set_mask = evtchn_2l_test_and_set_mask, |
| 365 | .mask = evtchn_2l_mask, |
| 366 | .unmask = evtchn_2l_unmask, |
| 367 | .handle_events = evtchn_2l_handle_events, |
Boris Ostrovsky | 5cec988 | 2015-04-29 17:10:12 -0400 | [diff] [blame] | 368 | .resume = evtchn_2l_resume, |
David Vrabel | ab9a1cc | 2013-03-14 12:49:19 +0000 | [diff] [blame] | 369 | }; |
| 370 | |
| 371 | void __init xen_evtchn_2l_init(void) |
| 372 | { |
| 373 | pr_info("Using 2-level ABI\n"); |
| 374 | evtchn_ops = &evtchn_ops_2l; |
| 375 | } |