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/io.h>
12 #include <linux/kernel.h>
13 #include <linux/mm.h>
14 #include <linux/slab.h>
15 #include <linux/vmalloc.h>
16 #include <linux/hyperv.h>
17 #include <linux/random.h>
18 #include <linux/clockchips.h>
19 #include <linux/delay.h>
20 #include <linux/interrupt.h>
21 #include <clocksource/hyperv_timer.h>
22 #include <asm/mshyperv.h>
23 #include <linux/set_memory.h>
24 #include "hyperv_vmbus.h"
25
26 /* The one and only */
27 struct hv_context hv_context;
28
29 /*
30 * hv_init - Main initialization routine.
31 *
32 * This routine must be called before any other routines in here are called
33 */
hv_init(void)34 int hv_init(void)
35 {
36 hv_context.cpu_context = alloc_percpu(struct hv_per_cpu_context);
37 if (!hv_context.cpu_context)
38 return -ENOMEM;
39 return 0;
40 }
41
42 /*
43 * hv_post_message - Post a message using the hypervisor message IPC.
44 *
45 * This involves a hypercall.
46 */
hv_post_message(union hv_connection_id connection_id,enum hv_message_type message_type,void * payload,size_t payload_size)47 int hv_post_message(union hv_connection_id connection_id,
48 enum hv_message_type message_type,
49 void *payload, size_t payload_size)
50 {
51 struct hv_input_post_message *aligned_msg;
52 unsigned long flags;
53 u64 status;
54
55 if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
56 return -EMSGSIZE;
57
58 local_irq_save(flags);
59
60 /*
61 * A TDX VM with the paravisor must use the decrypted post_msg_page: see
62 * the comment in struct hv_per_cpu_context. A SNP VM with the paravisor
63 * can use the encrypted hyperv_pcpu_input_arg because it copies the
64 * input into the GHCB page, which has been decrypted by the paravisor.
65 */
66 if (hv_isolation_type_tdx() && ms_hyperv.paravisor_present)
67 aligned_msg = this_cpu_ptr(hv_context.cpu_context)->post_msg_page;
68 else
69 aligned_msg = *this_cpu_ptr(hyperv_pcpu_input_arg);
70
71 aligned_msg->connectionid = connection_id;
72 aligned_msg->reserved = 0;
73 aligned_msg->message_type = message_type;
74 aligned_msg->payload_size = payload_size;
75 memcpy((void *)aligned_msg->payload, payload, payload_size);
76
77 if (ms_hyperv.paravisor_present) {
78 if (hv_isolation_type_tdx())
79 status = hv_tdx_hypercall(HVCALL_POST_MESSAGE,
80 virt_to_phys(aligned_msg), 0);
81 else if (hv_isolation_type_snp())
82 status = hv_ghcb_hypercall(HVCALL_POST_MESSAGE,
83 aligned_msg, NULL,
84 sizeof(*aligned_msg));
85 else
86 status = HV_STATUS_INVALID_PARAMETER;
87 } else {
88 status = hv_do_hypercall(HVCALL_POST_MESSAGE,
89 aligned_msg, NULL);
90 }
91
92 local_irq_restore(flags);
93
94 return hv_result(status);
95 }
96
hv_synic_alloc(void)97 int hv_synic_alloc(void)
98 {
99 int cpu, ret = -ENOMEM;
100 struct hv_per_cpu_context *hv_cpu;
101
102 /*
103 * First, zero all per-cpu memory areas so hv_synic_free() can
104 * detect what memory has been allocated and cleanup properly
105 * after any failures.
106 */
107 for_each_present_cpu(cpu) {
108 hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu);
109 memset(hv_cpu, 0, sizeof(*hv_cpu));
110 }
111
112 hv_context.hv_numa_map = kcalloc(nr_node_ids, sizeof(struct cpumask),
113 GFP_KERNEL);
114 if (hv_context.hv_numa_map == NULL) {
115 pr_err("Unable to allocate NUMA map\n");
116 goto err;
117 }
118
119 for_each_present_cpu(cpu) {
120 hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu);
121
122 tasklet_init(&hv_cpu->msg_dpc,
123 vmbus_on_msg_dpc, (unsigned long) hv_cpu);
124
125 if (ms_hyperv.paravisor_present && hv_isolation_type_tdx()) {
126 hv_cpu->post_msg_page = (void *)get_zeroed_page(GFP_ATOMIC);
127 if (hv_cpu->post_msg_page == NULL) {
128 pr_err("Unable to allocate post msg page\n");
129 goto err;
130 }
131
132 ret = set_memory_decrypted((unsigned long)hv_cpu->post_msg_page, 1);
133 if (ret) {
134 pr_err("Failed to decrypt post msg page: %d\n", ret);
135 /* Just leak the page, as it's unsafe to free the page. */
136 hv_cpu->post_msg_page = NULL;
137 goto err;
138 }
139
140 memset(hv_cpu->post_msg_page, 0, PAGE_SIZE);
141 }
142
143 /*
144 * Synic message and event pages are allocated by paravisor.
145 * Skip these pages allocation here.
146 */
147 if (!ms_hyperv.paravisor_present && !hv_root_partition) {
148 hv_cpu->synic_message_page =
149 (void *)get_zeroed_page(GFP_ATOMIC);
150 if (hv_cpu->synic_message_page == NULL) {
151 pr_err("Unable to allocate SYNIC message page\n");
152 goto err;
153 }
154
155 hv_cpu->synic_event_page =
156 (void *)get_zeroed_page(GFP_ATOMIC);
157 if (hv_cpu->synic_event_page == NULL) {
158 pr_err("Unable to allocate SYNIC event page\n");
159
160 free_page((unsigned long)hv_cpu->synic_message_page);
161 hv_cpu->synic_message_page = NULL;
162 goto err;
163 }
164 }
165
166 if (!ms_hyperv.paravisor_present &&
167 (hv_isolation_type_snp() || hv_isolation_type_tdx())) {
168 ret = set_memory_decrypted((unsigned long)
169 hv_cpu->synic_message_page, 1);
170 if (ret) {
171 pr_err("Failed to decrypt SYNIC msg page: %d\n", ret);
172 hv_cpu->synic_message_page = NULL;
173
174 /*
175 * Free the event page here so that hv_synic_free()
176 * won't later try to re-encrypt it.
177 */
178 free_page((unsigned long)hv_cpu->synic_event_page);
179 hv_cpu->synic_event_page = NULL;
180 goto err;
181 }
182
183 ret = set_memory_decrypted((unsigned long)
184 hv_cpu->synic_event_page, 1);
185 if (ret) {
186 pr_err("Failed to decrypt SYNIC event page: %d\n", ret);
187 hv_cpu->synic_event_page = NULL;
188 goto err;
189 }
190
191 memset(hv_cpu->synic_message_page, 0, PAGE_SIZE);
192 memset(hv_cpu->synic_event_page, 0, PAGE_SIZE);
193 }
194 }
195
196 return 0;
197
198 err:
199 /*
200 * Any memory allocations that succeeded will be freed when
201 * the caller cleans up by calling hv_synic_free()
202 */
203 return ret;
204 }
205
206
hv_synic_free(void)207 void hv_synic_free(void)
208 {
209 int cpu, ret;
210
211 for_each_present_cpu(cpu) {
212 struct hv_per_cpu_context *hv_cpu
213 = per_cpu_ptr(hv_context.cpu_context, cpu);
214
215 /* It's better to leak the page if the encryption fails. */
216 if (ms_hyperv.paravisor_present && hv_isolation_type_tdx()) {
217 if (hv_cpu->post_msg_page) {
218 ret = set_memory_encrypted((unsigned long)
219 hv_cpu->post_msg_page, 1);
220 if (ret) {
221 pr_err("Failed to encrypt post msg page: %d\n", ret);
222 hv_cpu->post_msg_page = NULL;
223 }
224 }
225 }
226
227 if (!ms_hyperv.paravisor_present &&
228 (hv_isolation_type_snp() || hv_isolation_type_tdx())) {
229 if (hv_cpu->synic_message_page) {
230 ret = set_memory_encrypted((unsigned long)
231 hv_cpu->synic_message_page, 1);
232 if (ret) {
233 pr_err("Failed to encrypt SYNIC msg page: %d\n", ret);
234 hv_cpu->synic_message_page = NULL;
235 }
236 }
237
238 if (hv_cpu->synic_event_page) {
239 ret = set_memory_encrypted((unsigned long)
240 hv_cpu->synic_event_page, 1);
241 if (ret) {
242 pr_err("Failed to encrypt SYNIC event page: %d\n", ret);
243 hv_cpu->synic_event_page = NULL;
244 }
245 }
246 }
247
248 free_page((unsigned long)hv_cpu->post_msg_page);
249 free_page((unsigned long)hv_cpu->synic_event_page);
250 free_page((unsigned long)hv_cpu->synic_message_page);
251 }
252
253 kfree(hv_context.hv_numa_map);
254 }
255
256 /*
257 * hv_synic_init - Initialize the Synthetic Interrupt Controller.
258 *
259 * If it is already initialized by another entity (ie x2v shim), we need to
260 * retrieve the initialized message and event pages. Otherwise, we create and
261 * initialize the message and event pages.
262 */
hv_synic_enable_regs(unsigned int cpu)263 void hv_synic_enable_regs(unsigned int cpu)
264 {
265 struct hv_per_cpu_context *hv_cpu
266 = per_cpu_ptr(hv_context.cpu_context, cpu);
267 union hv_synic_simp simp;
268 union hv_synic_siefp siefp;
269 union hv_synic_sint shared_sint;
270 union hv_synic_scontrol sctrl;
271
272 /* Setup the Synic's message page */
273 simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP);
274 simp.simp_enabled = 1;
275
276 if (ms_hyperv.paravisor_present || hv_root_partition) {
277 /* Mask out vTOM bit. ioremap_cache() maps decrypted */
278 u64 base = (simp.base_simp_gpa << HV_HYP_PAGE_SHIFT) &
279 ~ms_hyperv.shared_gpa_boundary;
280 hv_cpu->synic_message_page
281 = (void *)ioremap_cache(base, HV_HYP_PAGE_SIZE);
282 if (!hv_cpu->synic_message_page)
283 pr_err("Fail to map synic message page.\n");
284 } else {
285 simp.base_simp_gpa = virt_to_phys(hv_cpu->synic_message_page)
286 >> HV_HYP_PAGE_SHIFT;
287 }
288
289 hv_set_register(HV_REGISTER_SIMP, simp.as_uint64);
290
291 /* Setup the Synic's event page */
292 siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
293 siefp.siefp_enabled = 1;
294
295 if (ms_hyperv.paravisor_present || hv_root_partition) {
296 /* Mask out vTOM bit. ioremap_cache() maps decrypted */
297 u64 base = (siefp.base_siefp_gpa << HV_HYP_PAGE_SHIFT) &
298 ~ms_hyperv.shared_gpa_boundary;
299 hv_cpu->synic_event_page
300 = (void *)ioremap_cache(base, HV_HYP_PAGE_SIZE);
301 if (!hv_cpu->synic_event_page)
302 pr_err("Fail to map synic event page.\n");
303 } else {
304 siefp.base_siefp_gpa = virt_to_phys(hv_cpu->synic_event_page)
305 >> HV_HYP_PAGE_SHIFT;
306 }
307
308 hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64);
309
310 /* Setup the shared SINT. */
311 if (vmbus_irq != -1)
312 enable_percpu_irq(vmbus_irq, 0);
313 shared_sint.as_uint64 = hv_get_register(HV_REGISTER_SINT0 +
314 VMBUS_MESSAGE_SINT);
315
316 shared_sint.vector = vmbus_interrupt;
317 shared_sint.masked = false;
318
319 /*
320 * On architectures where Hyper-V doesn't support AEOI (e.g., ARM64),
321 * it doesn't provide a recommendation flag and AEOI must be disabled.
322 */
323 #ifdef HV_DEPRECATING_AEOI_RECOMMENDED
324 shared_sint.auto_eoi =
325 !(ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED);
326 #else
327 shared_sint.auto_eoi = 0;
328 #endif
329 hv_set_register(HV_REGISTER_SINT0 + VMBUS_MESSAGE_SINT,
330 shared_sint.as_uint64);
331
332 /* Enable the global synic bit */
333 sctrl.as_uint64 = hv_get_register(HV_REGISTER_SCONTROL);
334 sctrl.enable = 1;
335
336 hv_set_register(HV_REGISTER_SCONTROL, sctrl.as_uint64);
337 }
338
hv_synic_init(unsigned int cpu)339 int hv_synic_init(unsigned int cpu)
340 {
341 hv_synic_enable_regs(cpu);
342
343 hv_stimer_legacy_init(cpu, VMBUS_MESSAGE_SINT);
344
345 return 0;
346 }
347
348 /*
349 * hv_synic_cleanup - Cleanup routine for hv_synic_init().
350 */
hv_synic_disable_regs(unsigned int cpu)351 void hv_synic_disable_regs(unsigned int cpu)
352 {
353 struct hv_per_cpu_context *hv_cpu
354 = per_cpu_ptr(hv_context.cpu_context, cpu);
355 union hv_synic_sint shared_sint;
356 union hv_synic_simp simp;
357 union hv_synic_siefp siefp;
358 union hv_synic_scontrol sctrl;
359
360 shared_sint.as_uint64 = hv_get_register(HV_REGISTER_SINT0 +
361 VMBUS_MESSAGE_SINT);
362
363 shared_sint.masked = 1;
364
365 /* Need to correctly cleanup in the case of SMP!!! */
366 /* Disable the interrupt */
367 hv_set_register(HV_REGISTER_SINT0 + VMBUS_MESSAGE_SINT,
368 shared_sint.as_uint64);
369
370 simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP);
371 /*
372 * In Isolation VM, sim and sief pages are allocated by
373 * paravisor. These pages also will be used by kdump
374 * kernel. So just reset enable bit here and keep page
375 * addresses.
376 */
377 simp.simp_enabled = 0;
378 if (ms_hyperv.paravisor_present || hv_root_partition) {
379 iounmap(hv_cpu->synic_message_page);
380 hv_cpu->synic_message_page = NULL;
381 } else {
382 simp.base_simp_gpa = 0;
383 }
384
385 hv_set_register(HV_REGISTER_SIMP, simp.as_uint64);
386
387 siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
388 siefp.siefp_enabled = 0;
389
390 if (ms_hyperv.paravisor_present || hv_root_partition) {
391 iounmap(hv_cpu->synic_event_page);
392 hv_cpu->synic_event_page = NULL;
393 } else {
394 siefp.base_siefp_gpa = 0;
395 }
396
397 hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64);
398
399 /* Disable the global synic bit */
400 sctrl.as_uint64 = hv_get_register(HV_REGISTER_SCONTROL);
401 sctrl.enable = 0;
402 hv_set_register(HV_REGISTER_SCONTROL, sctrl.as_uint64);
403
404 if (vmbus_irq != -1)
405 disable_percpu_irq(vmbus_irq);
406 }
407
408 #define HV_MAX_TRIES 3
409 /*
410 * Scan the event flags page of 'this' CPU looking for any bit that is set. If we find one
411 * bit set, then wait for a few milliseconds. Repeat these steps for a maximum of 3 times.
412 * Return 'true', if there is still any set bit after this operation; 'false', otherwise.
413 *
414 * If a bit is set, that means there is a pending channel interrupt. The expectation is
415 * that the normal interrupt handling mechanism will find and process the channel interrupt
416 * "very soon", and in the process clear the bit.
417 */
hv_synic_event_pending(void)418 static bool hv_synic_event_pending(void)
419 {
420 struct hv_per_cpu_context *hv_cpu = this_cpu_ptr(hv_context.cpu_context);
421 union hv_synic_event_flags *event =
422 (union hv_synic_event_flags *)hv_cpu->synic_event_page + VMBUS_MESSAGE_SINT;
423 unsigned long *recv_int_page = event->flags; /* assumes VMBus version >= VERSION_WIN8 */
424 bool pending;
425 u32 relid;
426 int tries = 0;
427
428 retry:
429 pending = false;
430 for_each_set_bit(relid, recv_int_page, HV_EVENT_FLAGS_COUNT) {
431 /* Special case - VMBus channel protocol messages */
432 if (relid == 0)
433 continue;
434 pending = true;
435 break;
436 }
437 if (pending && tries++ < HV_MAX_TRIES) {
438 usleep_range(10000, 20000);
439 goto retry;
440 }
441 return pending;
442 }
443
hv_synic_cleanup(unsigned int cpu)444 int hv_synic_cleanup(unsigned int cpu)
445 {
446 struct vmbus_channel *channel, *sc;
447 bool channel_found = false;
448
449 if (vmbus_connection.conn_state != CONNECTED)
450 goto always_cleanup;
451
452 /*
453 * Hyper-V does not provide a way to change the connect CPU once
454 * it is set; we must prevent the connect CPU from going offline
455 * while the VM is running normally. But in the panic or kexec()
456 * path where the vmbus is already disconnected, the CPU must be
457 * allowed to shut down.
458 */
459 if (cpu == VMBUS_CONNECT_CPU)
460 return -EBUSY;
461
462 /*
463 * Search for channels which are bound to the CPU we're about to
464 * cleanup. In case we find one and vmbus is still connected, we
465 * fail; this will effectively prevent CPU offlining.
466 *
467 * TODO: Re-bind the channels to different CPUs.
468 */
469 mutex_lock(&vmbus_connection.channel_mutex);
470 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
471 if (channel->target_cpu == cpu) {
472 channel_found = true;
473 break;
474 }
475 list_for_each_entry(sc, &channel->sc_list, sc_list) {
476 if (sc->target_cpu == cpu) {
477 channel_found = true;
478 break;
479 }
480 }
481 if (channel_found)
482 break;
483 }
484 mutex_unlock(&vmbus_connection.channel_mutex);
485
486 if (channel_found)
487 return -EBUSY;
488
489 /*
490 * channel_found == false means that any channels that were previously
491 * assigned to the CPU have been reassigned elsewhere with a call of
492 * vmbus_send_modifychannel(). Scan the event flags page looking for
493 * bits that are set and waiting with a timeout for vmbus_chan_sched()
494 * to process such bits. If bits are still set after this operation
495 * and VMBus is connected, fail the CPU offlining operation.
496 */
497 if (vmbus_proto_version >= VERSION_WIN10_V4_1 && hv_synic_event_pending())
498 return -EBUSY;
499
500 always_cleanup:
501 hv_stimer_legacy_cleanup(cpu);
502
503 hv_synic_disable_regs(cpu);
504
505 return 0;
506 }
507