1 /*
2 * Copyright (c) 2009, Microsoft Corporation.
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms and conditions of the GNU General Public License,
6 * version 2, as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
11 * more details.
12 *
13 * You should have received a copy of the GNU General Public License along with
14 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
15 * Place - Suite 330, Boston, MA 02111-1307 USA.
16 *
17 * Authors:
18 * Haiyang Zhang <haiyangz@microsoft.com>
19 * Hank Janssen <hjanssen@microsoft.com>
20 *
21 */
22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23
24 #include <linux/kernel.h>
25 #include <linux/mm.h>
26 #include <linux/slab.h>
27 #include <linux/vmalloc.h>
28 #include <linux/hyperv.h>
29 #include <linux/version.h>
30 #include <linux/random.h>
31 #include <linux/clockchips.h>
32 #include <asm/mshyperv.h>
33 #include "hyperv_vmbus.h"
34
35 /* The one and only */
36 struct hv_context hv_context = {
37 .synic_initialized = false,
38 };
39
40 /*
41 * If false, we're using the old mechanism for stimer0 interrupts
42 * where it sends a VMbus message when it expires. The old
43 * mechanism is used when running on older versions of Hyper-V
44 * that don't support Direct Mode. While Hyper-V provides
45 * four stimer's per CPU, Linux uses only stimer0.
46 */
47 static bool direct_mode_enabled;
48 static int stimer0_irq;
49 static int stimer0_vector;
50
51 #define HV_TIMER_FREQUENCY (10 * 1000 * 1000) /* 100ns period */
52 #define HV_MAX_MAX_DELTA_TICKS 0xffffffff
53 #define HV_MIN_DELTA_TICKS 1
54
55 /*
56 * hv_init - Main initialization routine.
57 *
58 * This routine must be called before any other routines in here are called
59 */
hv_init(void)60 int hv_init(void)
61 {
62 hv_context.cpu_context = alloc_percpu(struct hv_per_cpu_context);
63 if (!hv_context.cpu_context)
64 return -ENOMEM;
65
66 direct_mode_enabled = ms_hyperv.misc_features &
67 HV_STIMER_DIRECT_MODE_AVAILABLE;
68 return 0;
69 }
70
71 /*
72 * hv_post_message - Post a message using the hypervisor message IPC.
73 *
74 * This involves a hypercall.
75 */
hv_post_message(union hv_connection_id connection_id,enum hv_message_type message_type,void * payload,size_t payload_size)76 int hv_post_message(union hv_connection_id connection_id,
77 enum hv_message_type message_type,
78 void *payload, size_t payload_size)
79 {
80 struct hv_input_post_message *aligned_msg;
81 struct hv_per_cpu_context *hv_cpu;
82 u64 status;
83
84 if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
85 return -EMSGSIZE;
86
87 hv_cpu = get_cpu_ptr(hv_context.cpu_context);
88 aligned_msg = hv_cpu->post_msg_page;
89 aligned_msg->connectionid = connection_id;
90 aligned_msg->reserved = 0;
91 aligned_msg->message_type = message_type;
92 aligned_msg->payload_size = payload_size;
93 memcpy((void *)aligned_msg->payload, payload, payload_size);
94
95 status = hv_do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL);
96
97 /* Preemption must remain disabled until after the hypercall
98 * so some other thread can't get scheduled onto this cpu and
99 * corrupt the per-cpu post_msg_page
100 */
101 put_cpu_ptr(hv_cpu);
102
103 return status & 0xFFFF;
104 }
105
106 /*
107 * ISR for when stimer0 is operating in Direct Mode. Direct Mode
108 * does not use VMbus or any VMbus messages, so process here and not
109 * in the VMbus driver code.
110 */
111
hv_stimer0_isr(void)112 static void hv_stimer0_isr(void)
113 {
114 struct hv_per_cpu_context *hv_cpu;
115
116 hv_cpu = this_cpu_ptr(hv_context.cpu_context);
117 hv_cpu->clk_evt->event_handler(hv_cpu->clk_evt);
118 add_interrupt_randomness(stimer0_vector, 0);
119 }
120
hv_ce_set_next_event(unsigned long delta,struct clock_event_device * evt)121 static int hv_ce_set_next_event(unsigned long delta,
122 struct clock_event_device *evt)
123 {
124 u64 current_tick;
125
126 WARN_ON(!clockevent_state_oneshot(evt));
127
128 current_tick = hyperv_cs->read(NULL);
129 current_tick += delta;
130 hv_init_timer(0, current_tick);
131 return 0;
132 }
133
hv_ce_shutdown(struct clock_event_device * evt)134 static int hv_ce_shutdown(struct clock_event_device *evt)
135 {
136 hv_init_timer(0, 0);
137 hv_init_timer_config(0, 0);
138 if (direct_mode_enabled)
139 hv_disable_stimer0_percpu_irq(stimer0_irq);
140
141 return 0;
142 }
143
hv_ce_set_oneshot(struct clock_event_device * evt)144 static int hv_ce_set_oneshot(struct clock_event_device *evt)
145 {
146 union hv_timer_config timer_cfg;
147
148 timer_cfg.as_uint64 = 0;
149 timer_cfg.enable = 1;
150 timer_cfg.auto_enable = 1;
151 if (direct_mode_enabled) {
152 /*
153 * When it expires, the timer will directly interrupt
154 * on the specified hardware vector/IRQ.
155 */
156 timer_cfg.direct_mode = 1;
157 timer_cfg.apic_vector = stimer0_vector;
158 hv_enable_stimer0_percpu_irq(stimer0_irq);
159 } else {
160 /*
161 * When it expires, the timer will generate a VMbus message,
162 * to be handled by the normal VMbus interrupt handler.
163 */
164 timer_cfg.direct_mode = 0;
165 timer_cfg.sintx = VMBUS_MESSAGE_SINT;
166 }
167 hv_init_timer_config(0, timer_cfg.as_uint64);
168 return 0;
169 }
170
hv_init_clockevent_device(struct clock_event_device * dev,int cpu)171 static void hv_init_clockevent_device(struct clock_event_device *dev, int cpu)
172 {
173 dev->name = "Hyper-V clockevent";
174 dev->features = CLOCK_EVT_FEAT_ONESHOT;
175 dev->cpumask = cpumask_of(cpu);
176 dev->rating = 1000;
177 /*
178 * Avoid settint dev->owner = THIS_MODULE deliberately as doing so will
179 * result in clockevents_config_and_register() taking additional
180 * references to the hv_vmbus module making it impossible to unload.
181 */
182
183 dev->set_state_shutdown = hv_ce_shutdown;
184 dev->set_state_oneshot = hv_ce_set_oneshot;
185 dev->set_next_event = hv_ce_set_next_event;
186 }
187
188
hv_synic_alloc(void)189 int hv_synic_alloc(void)
190 {
191 int cpu;
192
193 hv_context.hv_numa_map = kcalloc(nr_node_ids, sizeof(struct cpumask),
194 GFP_KERNEL);
195 if (hv_context.hv_numa_map == NULL) {
196 pr_err("Unable to allocate NUMA map\n");
197 goto err;
198 }
199
200 for_each_present_cpu(cpu) {
201 struct hv_per_cpu_context *hv_cpu
202 = per_cpu_ptr(hv_context.cpu_context, cpu);
203
204 memset(hv_cpu, 0, sizeof(*hv_cpu));
205 tasklet_init(&hv_cpu->msg_dpc,
206 vmbus_on_msg_dpc, (unsigned long) hv_cpu);
207
208 hv_cpu->clk_evt = kzalloc(sizeof(struct clock_event_device),
209 GFP_KERNEL);
210 if (hv_cpu->clk_evt == NULL) {
211 pr_err("Unable to allocate clock event device\n");
212 goto err;
213 }
214 hv_init_clockevent_device(hv_cpu->clk_evt, cpu);
215
216 hv_cpu->synic_message_page =
217 (void *)get_zeroed_page(GFP_ATOMIC);
218 if (hv_cpu->synic_message_page == NULL) {
219 pr_err("Unable to allocate SYNIC message page\n");
220 goto err;
221 }
222
223 hv_cpu->synic_event_page = (void *)get_zeroed_page(GFP_ATOMIC);
224 if (hv_cpu->synic_event_page == NULL) {
225 pr_err("Unable to allocate SYNIC event page\n");
226 goto err;
227 }
228
229 hv_cpu->post_msg_page = (void *)get_zeroed_page(GFP_ATOMIC);
230 if (hv_cpu->post_msg_page == NULL) {
231 pr_err("Unable to allocate post msg page\n");
232 goto err;
233 }
234
235 INIT_LIST_HEAD(&hv_cpu->chan_list);
236 }
237
238 if (direct_mode_enabled &&
239 hv_setup_stimer0_irq(&stimer0_irq, &stimer0_vector,
240 hv_stimer0_isr))
241 goto err;
242
243 return 0;
244 err:
245 /*
246 * Any memory allocations that succeeded will be freed when
247 * the caller cleans up by calling hv_synic_free()
248 */
249 return -ENOMEM;
250 }
251
252
hv_synic_free(void)253 void hv_synic_free(void)
254 {
255 int cpu;
256
257 for_each_present_cpu(cpu) {
258 struct hv_per_cpu_context *hv_cpu
259 = per_cpu_ptr(hv_context.cpu_context, cpu);
260
261 kfree(hv_cpu->clk_evt);
262 free_page((unsigned long)hv_cpu->synic_event_page);
263 free_page((unsigned long)hv_cpu->synic_message_page);
264 free_page((unsigned long)hv_cpu->post_msg_page);
265 }
266
267 kfree(hv_context.hv_numa_map);
268 }
269
270 /*
271 * hv_synic_init - Initialize the Synthetic Interrupt Controller.
272 *
273 * If it is already initialized by another entity (ie x2v shim), we need to
274 * retrieve the initialized message and event pages. Otherwise, we create and
275 * initialize the message and event pages.
276 */
hv_synic_init(unsigned int cpu)277 int hv_synic_init(unsigned int cpu)
278 {
279 struct hv_per_cpu_context *hv_cpu
280 = per_cpu_ptr(hv_context.cpu_context, cpu);
281 union hv_synic_simp simp;
282 union hv_synic_siefp siefp;
283 union hv_synic_sint shared_sint;
284 union hv_synic_scontrol sctrl;
285
286 /* Setup the Synic's message page */
287 hv_get_simp(simp.as_uint64);
288 simp.simp_enabled = 1;
289 simp.base_simp_gpa = virt_to_phys(hv_cpu->synic_message_page)
290 >> PAGE_SHIFT;
291
292 hv_set_simp(simp.as_uint64);
293
294 /* Setup the Synic's event page */
295 hv_get_siefp(siefp.as_uint64);
296 siefp.siefp_enabled = 1;
297 siefp.base_siefp_gpa = virt_to_phys(hv_cpu->synic_event_page)
298 >> PAGE_SHIFT;
299
300 hv_set_siefp(siefp.as_uint64);
301
302 /* Setup the shared SINT. */
303 hv_get_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
304
305 shared_sint.vector = HYPERVISOR_CALLBACK_VECTOR;
306 shared_sint.masked = false;
307 if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED)
308 shared_sint.auto_eoi = false;
309 else
310 shared_sint.auto_eoi = true;
311
312 hv_set_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
313
314 /* Enable the global synic bit */
315 hv_get_synic_state(sctrl.as_uint64);
316 sctrl.enable = 1;
317
318 hv_set_synic_state(sctrl.as_uint64);
319
320 hv_context.synic_initialized = true;
321
322 /*
323 * Register the per-cpu clockevent source.
324 */
325 if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE)
326 clockevents_config_and_register(hv_cpu->clk_evt,
327 HV_TIMER_FREQUENCY,
328 HV_MIN_DELTA_TICKS,
329 HV_MAX_MAX_DELTA_TICKS);
330 return 0;
331 }
332
333 /*
334 * hv_synic_clockevents_cleanup - Cleanup clockevent devices
335 */
hv_synic_clockevents_cleanup(void)336 void hv_synic_clockevents_cleanup(void)
337 {
338 int cpu;
339
340 if (!(ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE))
341 return;
342
343 if (direct_mode_enabled)
344 hv_remove_stimer0_irq(stimer0_irq);
345
346 for_each_present_cpu(cpu) {
347 struct hv_per_cpu_context *hv_cpu
348 = per_cpu_ptr(hv_context.cpu_context, cpu);
349
350 clockevents_unbind_device(hv_cpu->clk_evt, cpu);
351 }
352 }
353
354 /*
355 * hv_synic_cleanup - Cleanup routine for hv_synic_init().
356 */
hv_synic_cleanup(unsigned int cpu)357 int hv_synic_cleanup(unsigned int cpu)
358 {
359 union hv_synic_sint shared_sint;
360 union hv_synic_simp simp;
361 union hv_synic_siefp siefp;
362 union hv_synic_scontrol sctrl;
363 struct vmbus_channel *channel, *sc;
364 bool channel_found = false;
365 unsigned long flags;
366
367 if (!hv_context.synic_initialized)
368 return -EFAULT;
369
370 /*
371 * Search for channels which are bound to the CPU we're about to
372 * cleanup. In case we find one and vmbus is still connected we need to
373 * fail, this will effectively prevent CPU offlining. There is no way
374 * we can re-bind channels to different CPUs for now.
375 */
376 mutex_lock(&vmbus_connection.channel_mutex);
377 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
378 if (channel->target_cpu == cpu) {
379 channel_found = true;
380 break;
381 }
382 spin_lock_irqsave(&channel->lock, flags);
383 list_for_each_entry(sc, &channel->sc_list, sc_list) {
384 if (sc->target_cpu == cpu) {
385 channel_found = true;
386 break;
387 }
388 }
389 spin_unlock_irqrestore(&channel->lock, flags);
390 if (channel_found)
391 break;
392 }
393 mutex_unlock(&vmbus_connection.channel_mutex);
394
395 if (channel_found && vmbus_connection.conn_state == CONNECTED)
396 return -EBUSY;
397
398 /* Turn off clockevent device */
399 if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) {
400 struct hv_per_cpu_context *hv_cpu
401 = this_cpu_ptr(hv_context.cpu_context);
402
403 clockevents_unbind_device(hv_cpu->clk_evt, cpu);
404 hv_ce_shutdown(hv_cpu->clk_evt);
405 put_cpu_ptr(hv_cpu);
406 }
407
408 hv_get_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
409
410 shared_sint.masked = 1;
411
412 /* Need to correctly cleanup in the case of SMP!!! */
413 /* Disable the interrupt */
414 hv_set_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
415
416 hv_get_simp(simp.as_uint64);
417 simp.simp_enabled = 0;
418 simp.base_simp_gpa = 0;
419
420 hv_set_simp(simp.as_uint64);
421
422 hv_get_siefp(siefp.as_uint64);
423 siefp.siefp_enabled = 0;
424 siefp.base_siefp_gpa = 0;
425
426 hv_set_siefp(siefp.as_uint64);
427
428 /* Disable the global synic bit */
429 hv_get_synic_state(sctrl.as_uint64);
430 sctrl.enable = 0;
431 hv_set_synic_state(sctrl.as_uint64);
432
433 return 0;
434 }
435
