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 */
36struct hv_context hv_context;
37
38/*
39 * If false, we're using the old mechanism for stimer0 interrupts
40 * where it sends a VMbus message when it expires. The old
41 * mechanism is used when running on older versions of Hyper-V
42 * that don't support Direct Mode. While Hyper-V provides
43 * four stimer's per CPU, Linux uses only stimer0.
44 */
45static bool direct_mode_enabled;
46static int stimer0_irq;
47static int stimer0_vector;
48
49#define HV_TIMER_FREQUENCY (10 * 1000 * 1000) /* 100ns period */
50#define HV_MAX_MAX_DELTA_TICKS 0xffffffff
51#define HV_MIN_DELTA_TICKS 1
52
53/*
54 * hv_init - Main initialization routine.
55 *
56 * This routine must be called before any other routines in here are called
57 */
58int hv_init(void)
59{
60 hv_context.cpu_context = alloc_percpu(struct hv_per_cpu_context);
61 if (!hv_context.cpu_context)
62 return -ENOMEM;
63
64 direct_mode_enabled = ms_hyperv.misc_features &
65 HV_STIMER_DIRECT_MODE_AVAILABLE;
66 return 0;
67}
68
69/*
70 * hv_post_message - Post a message using the hypervisor message IPC.
71 *
72 * This involves a hypercall.
73 */
74int hv_post_message(union hv_connection_id connection_id,
75 enum hv_message_type message_type,
76 void *payload, size_t payload_size)
77{
78 struct hv_input_post_message *aligned_msg;
79 struct hv_per_cpu_context *hv_cpu;
80 u64 status;
81
82 if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
83 return -EMSGSIZE;
84
85 hv_cpu = get_cpu_ptr(hv_context.cpu_context);
86 aligned_msg = hv_cpu->post_msg_page;
87 aligned_msg->connectionid = connection_id;
88 aligned_msg->reserved = 0;
89 aligned_msg->message_type = message_type;
90 aligned_msg->payload_size = payload_size;
91 memcpy((void *)aligned_msg->payload, payload, payload_size);
92
93 status = hv_do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL);
94
95 /* Preemption must remain disabled until after the hypercall
96 * so some other thread can't get scheduled onto this cpu and
97 * corrupt the per-cpu post_msg_page
98 */
99 put_cpu_ptr(hv_cpu);
100
101 return status & 0xFFFF;
102}
103
104/*
105 * ISR for when stimer0 is operating in Direct Mode. Direct Mode
106 * does not use VMbus or any VMbus messages, so process here and not
107 * in the VMbus driver code.
108 */
109
110static void hv_stimer0_isr(void)
111{
112 struct hv_per_cpu_context *hv_cpu;
113
114 hv_cpu = this_cpu_ptr(hv_context.cpu_context);
115 hv_cpu->clk_evt->event_handler(hv_cpu->clk_evt);
116 add_interrupt_randomness(stimer0_vector, 0);
117}
118
119static int hv_ce_set_next_event(unsigned long delta,
120 struct clock_event_device *evt)
121{
122 u64 current_tick;
123
124 WARN_ON(!clockevent_state_oneshot(evt));
125
126 current_tick = hyperv_cs->read(NULL);
127 current_tick += delta;
128 hv_init_timer(0, current_tick);
129 return 0;
130}
131
132static int hv_ce_shutdown(struct clock_event_device *evt)
133{
134 hv_init_timer(0, 0);
135 hv_init_timer_config(0, 0);
136 if (direct_mode_enabled)
137 hv_disable_stimer0_percpu_irq(stimer0_irq);
138
139 return 0;
140}
141
142static int hv_ce_set_oneshot(struct clock_event_device *evt)
143{
144 union hv_stimer_config timer_cfg;
145
146 timer_cfg.as_uint64 = 0;
147 timer_cfg.enable = 1;
148 timer_cfg.auto_enable = 1;
149 if (direct_mode_enabled) {
150 /*
151 * When it expires, the timer will directly interrupt
152 * on the specified hardware vector/IRQ.
153 */
154 timer_cfg.direct_mode = 1;
155 timer_cfg.apic_vector = stimer0_vector;
156 hv_enable_stimer0_percpu_irq(stimer0_irq);
157 } else {
158 /*
159 * When it expires, the timer will generate a VMbus message,
160 * to be handled by the normal VMbus interrupt handler.
161 */
162 timer_cfg.direct_mode = 0;
163 timer_cfg.sintx = VMBUS_MESSAGE_SINT;
164 }
165 hv_init_timer_config(0, timer_cfg.as_uint64);
166 return 0;
167}
168
169static void hv_init_clockevent_device(struct clock_event_device *dev, int cpu)
170{
171 dev->name = "Hyper-V clockevent";
172 dev->features = CLOCK_EVT_FEAT_ONESHOT;
173 dev->cpumask = cpumask_of(cpu);
174 dev->rating = 1000;
175 /*
176 * Avoid settint dev->owner = THIS_MODULE deliberately as doing so will
177 * result in clockevents_config_and_register() taking additional
178 * references to the hv_vmbus module making it impossible to unload.
179 */
180
181 dev->set_state_shutdown = hv_ce_shutdown;
182 dev->set_state_oneshot = hv_ce_set_oneshot;
183 dev->set_next_event = hv_ce_set_next_event;
184}
185
186
187int hv_synic_alloc(void)
188{
189 int cpu;
190 struct hv_per_cpu_context *hv_cpu;
191
192 /*
193 * First, zero all per-cpu memory areas so hv_synic_free() can
194 * detect what memory has been allocated and cleanup properly
195 * after any failures.
196 */
197 for_each_present_cpu(cpu) {
198 hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu);
199 memset(hv_cpu, 0, sizeof(*hv_cpu));
200 }
201
202 hv_context.hv_numa_map = kcalloc(nr_node_ids, sizeof(struct cpumask),
203 GFP_KERNEL);
204 if (hv_context.hv_numa_map == NULL) {
205 pr_err("Unable to allocate NUMA map\n");
206 goto err;
207 }
208
209 for_each_present_cpu(cpu) {
210 hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu);
211
212 tasklet_init(&hv_cpu->msg_dpc,
213 vmbus_on_msg_dpc, (unsigned long) hv_cpu);
214
215 hv_cpu->clk_evt = kzalloc(sizeof(struct clock_event_device),
216 GFP_KERNEL);
217 if (hv_cpu->clk_evt == NULL) {
218 pr_err("Unable to allocate clock event device\n");
219 goto err;
220 }
221 hv_init_clockevent_device(hv_cpu->clk_evt, cpu);
222
223 hv_cpu->synic_message_page =
224 (void *)get_zeroed_page(GFP_ATOMIC);
225 if (hv_cpu->synic_message_page == NULL) {
226 pr_err("Unable to allocate SYNIC message page\n");
227 goto err;
228 }
229
230 hv_cpu->synic_event_page = (void *)get_zeroed_page(GFP_ATOMIC);
231 if (hv_cpu->synic_event_page == NULL) {
232 pr_err("Unable to allocate SYNIC event page\n");
233 goto err;
234 }
235
236 hv_cpu->post_msg_page = (void *)get_zeroed_page(GFP_ATOMIC);
237 if (hv_cpu->post_msg_page == NULL) {
238 pr_err("Unable to allocate post msg page\n");
239 goto err;
240 }
241
242 INIT_LIST_HEAD(&hv_cpu->chan_list);
243 }
244
245 if (direct_mode_enabled &&
246 hv_setup_stimer0_irq(&stimer0_irq, &stimer0_vector,
247 hv_stimer0_isr))
248 goto err;
249
250 return 0;
251err:
252 /*
253 * Any memory allocations that succeeded will be freed when
254 * the caller cleans up by calling hv_synic_free()
255 */
256 return -ENOMEM;
257}
258
259
260void hv_synic_free(void)
261{
262 int cpu;
263
264 for_each_present_cpu(cpu) {
265 struct hv_per_cpu_context *hv_cpu
266 = per_cpu_ptr(hv_context.cpu_context, cpu);
267
268 kfree(hv_cpu->clk_evt);
269 free_page((unsigned long)hv_cpu->synic_event_page);
270 free_page((unsigned long)hv_cpu->synic_message_page);
271 free_page((unsigned long)hv_cpu->post_msg_page);
272 }
273
274 kfree(hv_context.hv_numa_map);
275}
276
277/*
278 * hv_synic_init - Initialize the Synthetic Interrupt Controller.
279 *
280 * If it is already initialized by another entity (ie x2v shim), we need to
281 * retrieve the initialized message and event pages. Otherwise, we create and
282 * initialize the message and event pages.
283 */
284int hv_synic_init(unsigned int cpu)
285{
286 struct hv_per_cpu_context *hv_cpu
287 = per_cpu_ptr(hv_context.cpu_context, cpu);
288 union hv_synic_simp simp;
289 union hv_synic_siefp siefp;
290 union hv_synic_sint shared_sint;
291 union hv_synic_scontrol sctrl;
292
293 /* Setup the Synic's message page */
294 hv_get_simp(simp.as_uint64);
295 simp.simp_enabled = 1;
296 simp.base_simp_gpa = virt_to_phys(hv_cpu->synic_message_page)
297 >> PAGE_SHIFT;
298
299 hv_set_simp(simp.as_uint64);
300
301 /* Setup the Synic's event page */
302 hv_get_siefp(siefp.as_uint64);
303 siefp.siefp_enabled = 1;
304 siefp.base_siefp_gpa = virt_to_phys(hv_cpu->synic_event_page)
305 >> PAGE_SHIFT;
306
307 hv_set_siefp(siefp.as_uint64);
308
309 /* Setup the shared SINT. */
310 hv_get_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
311
312 shared_sint.vector = HYPERVISOR_CALLBACK_VECTOR;
313 shared_sint.masked = false;
314 if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED)
315 shared_sint.auto_eoi = false;
316 else
317 shared_sint.auto_eoi = true;
318
319 hv_set_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
320
321 /* Enable the global synic bit */
322 hv_get_synic_state(sctrl.as_uint64);
323 sctrl.enable = 1;
324
325 hv_set_synic_state(sctrl.as_uint64);
326
327 /*
328 * Register the per-cpu clockevent source.
329 */
330 if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE)
331 clockevents_config_and_register(hv_cpu->clk_evt,
332 HV_TIMER_FREQUENCY,
333 HV_MIN_DELTA_TICKS,
334 HV_MAX_MAX_DELTA_TICKS);
335 return 0;
336}
337
338/*
339 * hv_synic_clockevents_cleanup - Cleanup clockevent devices
340 */
341void hv_synic_clockevents_cleanup(void)
342{
343 int cpu;
344
345 if (!(ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE))
346 return;
347
348 if (direct_mode_enabled)
349 hv_remove_stimer0_irq(stimer0_irq);
350
351 for_each_present_cpu(cpu) {
352 struct hv_per_cpu_context *hv_cpu
353 = per_cpu_ptr(hv_context.cpu_context, cpu);
354
355 clockevents_unbind_device(hv_cpu->clk_evt, cpu);
356 }
357}
358
359/*
360 * hv_synic_cleanup - Cleanup routine for hv_synic_init().
361 */
362int hv_synic_cleanup(unsigned int cpu)
363{
364 union hv_synic_sint shared_sint;
365 union hv_synic_simp simp;
366 union hv_synic_siefp siefp;
367 union hv_synic_scontrol sctrl;
368 struct vmbus_channel *channel, *sc;
369 bool channel_found = false;
370 unsigned long flags;
371
372 hv_get_synic_state(sctrl.as_uint64);
373 if (sctrl.enable != 1)
374 return -EFAULT;
375
376 /*
377 * Search for channels which are bound to the CPU we're about to
378 * cleanup. In case we find one and vmbus is still connected we need to
379 * fail, this will effectively prevent CPU offlining. There is no way
380 * we can re-bind channels to different CPUs for now.
381 */
382 mutex_lock(&vmbus_connection.channel_mutex);
383 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
384 if (channel->target_cpu == cpu) {
385 channel_found = true;
386 break;
387 }
388 spin_lock_irqsave(&channel->lock, flags);
389 list_for_each_entry(sc, &channel->sc_list, sc_list) {
390 if (sc->target_cpu == cpu) {
391 channel_found = true;
392 break;
393 }
394 }
395 spin_unlock_irqrestore(&channel->lock, flags);
396 if (channel_found)
397 break;
398 }
399 mutex_unlock(&vmbus_connection.channel_mutex);
400
401 if (channel_found && vmbus_connection.conn_state == CONNECTED)
402 return -EBUSY;
403
404 /* Turn off clockevent device */
405 if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) {
406 struct hv_per_cpu_context *hv_cpu
407 = this_cpu_ptr(hv_context.cpu_context);
408
409 clockevents_unbind_device(hv_cpu->clk_evt, cpu);
410 hv_ce_shutdown(hv_cpu->clk_evt);
411 put_cpu_ptr(hv_cpu);
412 }
413
414 hv_get_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
415
416 shared_sint.masked = 1;
417
418 /* Need to correctly cleanup in the case of SMP!!! */
419 /* Disable the interrupt */
420 hv_set_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
421
422 hv_get_simp(simp.as_uint64);
423 simp.simp_enabled = 0;
424 simp.base_simp_gpa = 0;
425
426 hv_set_simp(simp.as_uint64);
427
428 hv_get_siefp(siefp.as_uint64);
429 siefp.siefp_enabled = 0;
430 siefp.base_siefp_gpa = 0;
431
432 hv_set_siefp(siefp.as_uint64);
433
434 /* Disable the global synic bit */
435 sctrl.enable = 0;
436 hv_set_synic_state(sctrl.as_uint64);
437
438 return 0;
439}
440