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