1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2009, Microsoft Corporation.
4 *
5 * Authors:
6 * Haiyang Zhang <haiyangz@microsoft.com>
7 * Hank Janssen <hjanssen@microsoft.com>
8 */
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11 #include <linux/kernel.h>
12 #include <linux/mm.h>
13 #include <linux/slab.h>
14 #include <linux/vmalloc.h>
15 #include <linux/hyperv.h>
16 #include <linux/random.h>
17 #include <linux/clockchips.h>
18 #include <linux/delay.h>
19 #include <linux/interrupt.h>
20 #include <clocksource/hyperv_timer.h>
21 #include <asm/mshyperv.h>
22 #include "hyperv_vmbus.h"
23
24 /* The one and only */
25 struct hv_context hv_context;
26
27 /*
28 * hv_init - Main initialization routine.
29 *
30 * This routine must be called before any other routines in here are called
31 */
hv_init(void)32 int hv_init(void)
33 {
34 hv_context.cpu_context = alloc_percpu(struct hv_per_cpu_context);
35 if (!hv_context.cpu_context)
36 return -ENOMEM;
37 return 0;
38 }
39
40 /*
41 * Functions for allocating and freeing memory with size and
42 * alignment HV_HYP_PAGE_SIZE. These functions are needed because
43 * the guest page size may not be the same as the Hyper-V page
44 * size. We depend upon kmalloc() aligning power-of-two size
45 * allocations to the allocation size boundary, so that the
46 * allocated memory appears to Hyper-V as a page of the size
47 * it expects.
48 */
49
hv_alloc_hyperv_page(void)50 void *hv_alloc_hyperv_page(void)
51 {
52 BUILD_BUG_ON(PAGE_SIZE < HV_HYP_PAGE_SIZE);
53
54 if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
55 return (void *)__get_free_page(GFP_KERNEL);
56 else
57 return kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
58 }
59
hv_alloc_hyperv_zeroed_page(void)60 void *hv_alloc_hyperv_zeroed_page(void)
61 {
62 if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
63 return (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
64 else
65 return kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
66 }
67
hv_free_hyperv_page(unsigned long addr)68 void hv_free_hyperv_page(unsigned long addr)
69 {
70 if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
71 free_page(addr);
72 else
73 kfree((void *)addr);
74 }
75
76 /*
77 * hv_post_message - Post a message using the hypervisor message IPC.
78 *
79 * This involves a hypercall.
80 */
hv_post_message(union hv_connection_id connection_id,enum hv_message_type message_type,void * payload,size_t payload_size)81 int hv_post_message(union hv_connection_id connection_id,
82 enum hv_message_type message_type,
83 void *payload, size_t payload_size)
84 {
85 struct hv_input_post_message *aligned_msg;
86 struct hv_per_cpu_context *hv_cpu;
87 u64 status;
88
89 if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
90 return -EMSGSIZE;
91
92 hv_cpu = get_cpu_ptr(hv_context.cpu_context);
93 aligned_msg = hv_cpu->post_msg_page;
94 aligned_msg->connectionid = connection_id;
95 aligned_msg->reserved = 0;
96 aligned_msg->message_type = message_type;
97 aligned_msg->payload_size = payload_size;
98 memcpy((void *)aligned_msg->payload, payload, payload_size);
99
100 status = hv_do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL);
101
102 /* Preemption must remain disabled until after the hypercall
103 * so some other thread can't get scheduled onto this cpu and
104 * corrupt the per-cpu post_msg_page
105 */
106 put_cpu_ptr(hv_cpu);
107
108 return hv_result(status);
109 }
110
hv_synic_alloc(void)111 int hv_synic_alloc(void)
112 {
113 int cpu;
114 struct hv_per_cpu_context *hv_cpu;
115
116 /*
117 * First, zero all per-cpu memory areas so hv_synic_free() can
118 * detect what memory has been allocated and cleanup properly
119 * after any failures.
120 */
121 for_each_present_cpu(cpu) {
122 hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu);
123 memset(hv_cpu, 0, sizeof(*hv_cpu));
124 }
125
126 hv_context.hv_numa_map = kcalloc(nr_node_ids, sizeof(struct cpumask),
127 GFP_KERNEL);
128 if (hv_context.hv_numa_map == NULL) {
129 pr_err("Unable to allocate NUMA map\n");
130 goto err;
131 }
132
133 for_each_present_cpu(cpu) {
134 hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu);
135
136 tasklet_init(&hv_cpu->msg_dpc,
137 vmbus_on_msg_dpc, (unsigned long) hv_cpu);
138
139 hv_cpu->synic_message_page =
140 (void *)get_zeroed_page(GFP_ATOMIC);
141 if (hv_cpu->synic_message_page == NULL) {
142 pr_err("Unable to allocate SYNIC message page\n");
143 goto err;
144 }
145
146 hv_cpu->synic_event_page = (void *)get_zeroed_page(GFP_ATOMIC);
147 if (hv_cpu->synic_event_page == NULL) {
148 pr_err("Unable to allocate SYNIC event page\n");
149 goto err;
150 }
151
152 hv_cpu->post_msg_page = (void *)get_zeroed_page(GFP_ATOMIC);
153 if (hv_cpu->post_msg_page == NULL) {
154 pr_err("Unable to allocate post msg page\n");
155 goto err;
156 }
157 }
158
159 return 0;
160 err:
161 /*
162 * Any memory allocations that succeeded will be freed when
163 * the caller cleans up by calling hv_synic_free()
164 */
165 return -ENOMEM;
166 }
167
168
hv_synic_free(void)169 void hv_synic_free(void)
170 {
171 int cpu;
172
173 for_each_present_cpu(cpu) {
174 struct hv_per_cpu_context *hv_cpu
175 = per_cpu_ptr(hv_context.cpu_context, cpu);
176
177 free_page((unsigned long)hv_cpu->synic_event_page);
178 free_page((unsigned long)hv_cpu->synic_message_page);
179 free_page((unsigned long)hv_cpu->post_msg_page);
180 }
181
182 kfree(hv_context.hv_numa_map);
183 }
184
185 /*
186 * hv_synic_init - Initialize the Synthetic Interrupt Controller.
187 *
188 * If it is already initialized by another entity (ie x2v shim), we need to
189 * retrieve the initialized message and event pages. Otherwise, we create and
190 * initialize the message and event pages.
191 */
hv_synic_enable_regs(unsigned int cpu)192 void hv_synic_enable_regs(unsigned int cpu)
193 {
194 struct hv_per_cpu_context *hv_cpu
195 = per_cpu_ptr(hv_context.cpu_context, cpu);
196 union hv_synic_simp simp;
197 union hv_synic_siefp siefp;
198 union hv_synic_sint shared_sint;
199 union hv_synic_scontrol sctrl;
200
201 /* Setup the Synic's message page */
202 simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP);
203 simp.simp_enabled = 1;
204 simp.base_simp_gpa = virt_to_phys(hv_cpu->synic_message_page)
205 >> HV_HYP_PAGE_SHIFT;
206
207 hv_set_register(HV_REGISTER_SIMP, simp.as_uint64);
208
209 /* Setup the Synic's event page */
210 siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
211 siefp.siefp_enabled = 1;
212 siefp.base_siefp_gpa = virt_to_phys(hv_cpu->synic_event_page)
213 >> HV_HYP_PAGE_SHIFT;
214
215 hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64);
216
217 /* Setup the shared SINT. */
218 if (vmbus_irq != -1)
219 enable_percpu_irq(vmbus_irq, 0);
220 shared_sint.as_uint64 = hv_get_register(HV_REGISTER_SINT0 +
221 VMBUS_MESSAGE_SINT);
222
223 shared_sint.vector = vmbus_interrupt;
224 shared_sint.masked = false;
225
226 /*
227 * On architectures where Hyper-V doesn't support AEOI (e.g., ARM64),
228 * it doesn't provide a recommendation flag and AEOI must be disabled.
229 */
230 #ifdef HV_DEPRECATING_AEOI_RECOMMENDED
231 shared_sint.auto_eoi =
232 !(ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED);
233 #else
234 shared_sint.auto_eoi = 0;
235 #endif
236 hv_set_register(HV_REGISTER_SINT0 + VMBUS_MESSAGE_SINT,
237 shared_sint.as_uint64);
238
239 /* Enable the global synic bit */
240 sctrl.as_uint64 = hv_get_register(HV_REGISTER_SCONTROL);
241 sctrl.enable = 1;
242
243 hv_set_register(HV_REGISTER_SCONTROL, sctrl.as_uint64);
244 }
245
hv_synic_init(unsigned int cpu)246 int hv_synic_init(unsigned int cpu)
247 {
248 hv_synic_enable_regs(cpu);
249
250 hv_stimer_legacy_init(cpu, VMBUS_MESSAGE_SINT);
251
252 return 0;
253 }
254
255 /*
256 * hv_synic_cleanup - Cleanup routine for hv_synic_init().
257 */
hv_synic_disable_regs(unsigned int cpu)258 void hv_synic_disable_regs(unsigned int cpu)
259 {
260 union hv_synic_sint shared_sint;
261 union hv_synic_simp simp;
262 union hv_synic_siefp siefp;
263 union hv_synic_scontrol sctrl;
264
265 shared_sint.as_uint64 = hv_get_register(HV_REGISTER_SINT0 +
266 VMBUS_MESSAGE_SINT);
267
268 shared_sint.masked = 1;
269
270 /* Need to correctly cleanup in the case of SMP!!! */
271 /* Disable the interrupt */
272 hv_set_register(HV_REGISTER_SINT0 + VMBUS_MESSAGE_SINT,
273 shared_sint.as_uint64);
274
275 simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP);
276 simp.simp_enabled = 0;
277 simp.base_simp_gpa = 0;
278
279 hv_set_register(HV_REGISTER_SIMP, simp.as_uint64);
280
281 siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
282 siefp.siefp_enabled = 0;
283 siefp.base_siefp_gpa = 0;
284
285 hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64);
286
287 /* Disable the global synic bit */
288 sctrl.as_uint64 = hv_get_register(HV_REGISTER_SCONTROL);
289 sctrl.enable = 0;
290 hv_set_register(HV_REGISTER_SCONTROL, sctrl.as_uint64);
291
292 if (vmbus_irq != -1)
293 disable_percpu_irq(vmbus_irq);
294 }
295
296 #define HV_MAX_TRIES 3
297 /*
298 * Scan the event flags page of 'this' CPU looking for any bit that is set. If we find one
299 * bit set, then wait for a few milliseconds. Repeat these steps for a maximum of 3 times.
300 * Return 'true', if there is still any set bit after this operation; 'false', otherwise.
301 *
302 * If a bit is set, that means there is a pending channel interrupt. The expectation is
303 * that the normal interrupt handling mechanism will find and process the channel interrupt
304 * "very soon", and in the process clear the bit.
305 */
hv_synic_event_pending(void)306 static bool hv_synic_event_pending(void)
307 {
308 struct hv_per_cpu_context *hv_cpu = this_cpu_ptr(hv_context.cpu_context);
309 union hv_synic_event_flags *event =
310 (union hv_synic_event_flags *)hv_cpu->synic_event_page + VMBUS_MESSAGE_SINT;
311 unsigned long *recv_int_page = event->flags; /* assumes VMBus version >= VERSION_WIN8 */
312 bool pending;
313 u32 relid;
314 int tries = 0;
315
316 retry:
317 pending = false;
318 for_each_set_bit(relid, recv_int_page, HV_EVENT_FLAGS_COUNT) {
319 /* Special case - VMBus channel protocol messages */
320 if (relid == 0)
321 continue;
322 pending = true;
323 break;
324 }
325 if (pending && tries++ < HV_MAX_TRIES) {
326 usleep_range(10000, 20000);
327 goto retry;
328 }
329 return pending;
330 }
331
hv_synic_cleanup(unsigned int cpu)332 int hv_synic_cleanup(unsigned int cpu)
333 {
334 struct vmbus_channel *channel, *sc;
335 bool channel_found = false;
336
337 if (vmbus_connection.conn_state != CONNECTED)
338 goto always_cleanup;
339
340 /*
341 * Hyper-V does not provide a way to change the connect CPU once
342 * it is set; we must prevent the connect CPU from going offline
343 * while the VM is running normally. But in the panic or kexec()
344 * path where the vmbus is already disconnected, the CPU must be
345 * allowed to shut down.
346 */
347 if (cpu == VMBUS_CONNECT_CPU)
348 return -EBUSY;
349
350 /*
351 * Search for channels which are bound to the CPU we're about to
352 * cleanup. In case we find one and vmbus is still connected, we
353 * fail; this will effectively prevent CPU offlining.
354 *
355 * TODO: Re-bind the channels to different CPUs.
356 */
357 mutex_lock(&vmbus_connection.channel_mutex);
358 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
359 if (channel->target_cpu == cpu) {
360 channel_found = true;
361 break;
362 }
363 list_for_each_entry(sc, &channel->sc_list, sc_list) {
364 if (sc->target_cpu == cpu) {
365 channel_found = true;
366 break;
367 }
368 }
369 if (channel_found)
370 break;
371 }
372 mutex_unlock(&vmbus_connection.channel_mutex);
373
374 if (channel_found)
375 return -EBUSY;
376
377 /*
378 * channel_found == false means that any channels that were previously
379 * assigned to the CPU have been reassigned elsewhere with a call of
380 * vmbus_send_modifychannel(). Scan the event flags page looking for
381 * bits that are set and waiting with a timeout for vmbus_chan_sched()
382 * to process such bits. If bits are still set after this operation
383 * and VMBus is connected, fail the CPU offlining operation.
384 */
385 if (vmbus_proto_version >= VERSION_WIN10_V4_1 && hv_synic_event_pending())
386 return -EBUSY;
387
388 always_cleanup:
389 hv_stimer_legacy_cleanup(cpu);
390
391 hv_synic_disable_regs(cpu);
392
393 return 0;
394 }
395