xref: /openbmc/linux/arch/arm/xen/enlighten.c (revision ba936421) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <xen/xen.h>
3 #include <xen/events.h>
4 #include <xen/grant_table.h>
5 #include <xen/hvm.h>
6 #include <xen/interface/vcpu.h>
7 #include <xen/interface/xen.h>
8 #include <xen/interface/memory.h>
9 #include <xen/interface/hvm/params.h>
10 #include <xen/features.h>
11 #include <xen/platform_pci.h>
12 #include <xen/xenbus.h>
13 #include <xen/page.h>
14 #include <xen/interface/sched.h>
15 #include <xen/xen-ops.h>
16 #include <asm/xen/hypervisor.h>
17 #include <asm/xen/hypercall.h>
18 #include <asm/system_misc.h>
19 #include <asm/efi.h>
20 #include <linux/interrupt.h>
21 #include <linux/irqreturn.h>
22 #include <linux/module.h>
23 #include <linux/of.h>
24 #include <linux/of_fdt.h>
25 #include <linux/of_irq.h>
26 #include <linux/of_address.h>
27 #include <linux/cpuidle.h>
28 #include <linux/cpufreq.h>
29 #include <linux/cpu.h>
30 #include <linux/console.h>
31 #include <linux/pvclock_gtod.h>
32 #include <linux/reboot.h>
33 #include <linux/time64.h>
34 #include <linux/timekeeping.h>
35 #include <linux/timekeeper_internal.h>
36 #include <linux/acpi.h>
37 
38 #include <linux/mm.h>
39 
40 static struct start_info _xen_start_info;
41 struct start_info *xen_start_info = &_xen_start_info;
42 EXPORT_SYMBOL(xen_start_info);
43 
44 enum xen_domain_type xen_domain_type = XEN_NATIVE;
45 EXPORT_SYMBOL(xen_domain_type);
46 
47 struct shared_info xen_dummy_shared_info;
48 struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info;
49 
50 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
51 static struct vcpu_info __percpu *xen_vcpu_info;
52 
53 /* Linux <-> Xen vCPU id mapping */
54 DEFINE_PER_CPU(uint32_t, xen_vcpu_id);
55 EXPORT_PER_CPU_SYMBOL(xen_vcpu_id);
56 
57 /* These are unused until we support booting "pre-ballooned" */
58 unsigned long xen_released_pages;
59 struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
60 
61 static __read_mostly unsigned int xen_events_irq;
62 static __read_mostly phys_addr_t xen_grant_frames;
63 
64 #define GRANT_TABLE_INDEX   0
65 #define EXT_REGION_INDEX    1
66 
67 uint32_t xen_start_flags;
68 EXPORT_SYMBOL(xen_start_flags);
69 
70 int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
71 			       int nr, struct page **pages)
72 {
73 	return xen_xlate_unmap_gfn_range(vma, nr, pages);
74 }
75 EXPORT_SYMBOL_GPL(xen_unmap_domain_gfn_range);
76 
77 static void xen_read_wallclock(struct timespec64 *ts)
78 {
79 	u32 version;
80 	struct timespec64 now, ts_monotonic;
81 	struct shared_info *s = HYPERVISOR_shared_info;
82 	struct pvclock_wall_clock *wall_clock = &(s->wc);
83 
84 	/* get wallclock at system boot */
85 	do {
86 		version = wall_clock->version;
87 		rmb();		/* fetch version before time */
88 		now.tv_sec  = ((uint64_t)wall_clock->sec_hi << 32) | wall_clock->sec;
89 		now.tv_nsec = wall_clock->nsec;
90 		rmb();		/* fetch time before checking version */
91 	} while ((wall_clock->version & 1) || (version != wall_clock->version));
92 
93 	/* time since system boot */
94 	ktime_get_ts64(&ts_monotonic);
95 	*ts = timespec64_add(now, ts_monotonic);
96 }
97 
98 static int xen_pvclock_gtod_notify(struct notifier_block *nb,
99 				   unsigned long was_set, void *priv)
100 {
101 	/* Protected by the calling core code serialization */
102 	static struct timespec64 next_sync;
103 
104 	struct xen_platform_op op;
105 	struct timespec64 now, system_time;
106 	struct timekeeper *tk = priv;
107 
108 	now.tv_sec = tk->xtime_sec;
109 	now.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
110 	system_time = timespec64_add(now, tk->wall_to_monotonic);
111 
112 	/*
113 	 * We only take the expensive HV call when the clock was set
114 	 * or when the 11 minutes RTC synchronization time elapsed.
115 	 */
116 	if (!was_set && timespec64_compare(&now, &next_sync) < 0)
117 		return NOTIFY_OK;
118 
119 	op.cmd = XENPF_settime64;
120 	op.u.settime64.mbz = 0;
121 	op.u.settime64.secs = now.tv_sec;
122 	op.u.settime64.nsecs = now.tv_nsec;
123 	op.u.settime64.system_time = timespec64_to_ns(&system_time);
124 	(void)HYPERVISOR_platform_op(&op);
125 
126 	/*
127 	 * Move the next drift compensation time 11 minutes
128 	 * ahead. That's emulating the sync_cmos_clock() update for
129 	 * the hardware RTC.
130 	 */
131 	next_sync = now;
132 	next_sync.tv_sec += 11 * 60;
133 
134 	return NOTIFY_OK;
135 }
136 
137 static struct notifier_block xen_pvclock_gtod_notifier = {
138 	.notifier_call = xen_pvclock_gtod_notify,
139 };
140 
141 static int xen_starting_cpu(unsigned int cpu)
142 {
143 	struct vcpu_register_vcpu_info info;
144 	struct vcpu_info *vcpup;
145 	int err;
146 
147 	/*
148 	 * VCPUOP_register_vcpu_info cannot be called twice for the same
149 	 * vcpu, so if vcpu_info is already registered, just get out. This
150 	 * can happen with cpu-hotplug.
151 	 */
152 	if (per_cpu(xen_vcpu, cpu) != NULL)
153 		goto after_register_vcpu_info;
154 
155 	pr_info("Xen: initializing cpu%d\n", cpu);
156 	vcpup = per_cpu_ptr(xen_vcpu_info, cpu);
157 
158 	info.mfn = percpu_to_gfn(vcpup);
159 	info.offset = xen_offset_in_page(vcpup);
160 
161 	err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu),
162 				 &info);
163 	BUG_ON(err);
164 	per_cpu(xen_vcpu, cpu) = vcpup;
165 
166 	if (!xen_kernel_unmapped_at_usr())
167 		xen_setup_runstate_info(cpu);
168 
169 after_register_vcpu_info:
170 	enable_percpu_irq(xen_events_irq, 0);
171 	return 0;
172 }
173 
174 static int xen_dying_cpu(unsigned int cpu)
175 {
176 	disable_percpu_irq(xen_events_irq);
177 	return 0;
178 }
179 
180 void xen_reboot(int reason)
181 {
182 	struct sched_shutdown r = { .reason = reason };
183 	int rc;
184 
185 	rc = HYPERVISOR_sched_op(SCHEDOP_shutdown, &r);
186 	BUG_ON(rc);
187 }
188 
189 static int xen_restart(struct notifier_block *nb, unsigned long action,
190 		       void *data)
191 {
192 	xen_reboot(SHUTDOWN_reboot);
193 
194 	return NOTIFY_DONE;
195 }
196 
197 static struct notifier_block xen_restart_nb = {
198 	.notifier_call = xen_restart,
199 	.priority = 192,
200 };
201 
202 static void xen_power_off(void)
203 {
204 	xen_reboot(SHUTDOWN_poweroff);
205 }
206 
207 static irqreturn_t xen_arm_callback(int irq, void *arg)
208 {
209 	xen_hvm_evtchn_do_upcall();
210 	return IRQ_HANDLED;
211 }
212 
213 static __initdata struct {
214 	const char *compat;
215 	const char *prefix;
216 	const char *version;
217 	bool found;
218 } hyper_node = {"xen,xen", "xen,xen-", NULL, false};
219 
220 static int __init fdt_find_hyper_node(unsigned long node, const char *uname,
221 				      int depth, void *data)
222 {
223 	const void *s = NULL;
224 	int len;
225 
226 	if (depth != 1 || strcmp(uname, "hypervisor") != 0)
227 		return 0;
228 
229 	if (of_flat_dt_is_compatible(node, hyper_node.compat))
230 		hyper_node.found = true;
231 
232 	s = of_get_flat_dt_prop(node, "compatible", &len);
233 	if (strlen(hyper_node.prefix) + 3  < len &&
234 	    !strncmp(hyper_node.prefix, s, strlen(hyper_node.prefix)))
235 		hyper_node.version = s + strlen(hyper_node.prefix);
236 
237 	/*
238 	 * Check if Xen supports EFI by checking whether there is the
239 	 * "/hypervisor/uefi" node in DT. If so, runtime services are available
240 	 * through proxy functions (e.g. in case of Xen dom0 EFI implementation
241 	 * they call special hypercall which executes relevant EFI functions)
242 	 * and that is why they are always enabled.
243 	 */
244 	if (IS_ENABLED(CONFIG_XEN_EFI)) {
245 		if ((of_get_flat_dt_subnode_by_name(node, "uefi") > 0) &&
246 		    !efi_runtime_disabled())
247 			set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
248 	}
249 
250 	return 0;
251 }
252 
253 /*
254  * see Documentation/devicetree/bindings/arm/xen.txt for the
255  * documentation of the Xen Device Tree format.
256  */
257 void __init xen_early_init(void)
258 {
259 	of_scan_flat_dt(fdt_find_hyper_node, NULL);
260 	if (!hyper_node.found) {
261 		pr_debug("No Xen support\n");
262 		return;
263 	}
264 
265 	if (hyper_node.version == NULL) {
266 		pr_debug("Xen version not found\n");
267 		return;
268 	}
269 
270 	pr_info("Xen %s support found\n", hyper_node.version);
271 
272 	xen_domain_type = XEN_HVM_DOMAIN;
273 
274 	xen_setup_features();
275 
276 	if (xen_feature(XENFEAT_dom0))
277 		xen_start_flags |= SIF_INITDOMAIN|SIF_PRIVILEGED;
278 
279 	if (!console_set_on_cmdline && !xen_initial_domain())
280 		add_preferred_console("hvc", 0, NULL);
281 }
282 
283 static void __init xen_acpi_guest_init(void)
284 {
285 #ifdef CONFIG_ACPI
286 	struct xen_hvm_param a;
287 	int interrupt, trigger, polarity;
288 
289 	a.domid = DOMID_SELF;
290 	a.index = HVM_PARAM_CALLBACK_IRQ;
291 
292 	if (HYPERVISOR_hvm_op(HVMOP_get_param, &a)
293 	    || (a.value >> 56) != HVM_PARAM_CALLBACK_TYPE_PPI) {
294 		xen_events_irq = 0;
295 		return;
296 	}
297 
298 	interrupt = a.value & 0xff;
299 	trigger = ((a.value >> 8) & 0x1) ? ACPI_EDGE_SENSITIVE
300 					 : ACPI_LEVEL_SENSITIVE;
301 	polarity = ((a.value >> 8) & 0x2) ? ACPI_ACTIVE_LOW
302 					  : ACPI_ACTIVE_HIGH;
303 	xen_events_irq = acpi_register_gsi(NULL, interrupt, trigger, polarity);
304 #endif
305 }
306 
307 #ifdef CONFIG_XEN_UNPOPULATED_ALLOC
308 /*
309  * A type-less specific Xen resource which contains extended regions
310  * (unused regions of guest physical address space provided by the hypervisor).
311  */
312 static struct resource xen_resource = {
313 	.name = "Xen unused space",
314 };
315 
316 int __init arch_xen_unpopulated_init(struct resource **res)
317 {
318 	struct device_node *np;
319 	struct resource *regs, *tmp_res;
320 	uint64_t min_gpaddr = -1, max_gpaddr = 0;
321 	unsigned int i, nr_reg = 0;
322 	int rc;
323 
324 	if (!xen_domain())
325 		return -ENODEV;
326 
327 	if (!acpi_disabled)
328 		return -ENODEV;
329 
330 	np = of_find_compatible_node(NULL, NULL, "xen,xen");
331 	if (WARN_ON(!np))
332 		return -ENODEV;
333 
334 	/* Skip region 0 which is reserved for grant table space */
335 	while (of_get_address(np, nr_reg + EXT_REGION_INDEX, NULL, NULL))
336 		nr_reg++;
337 
338 	if (!nr_reg) {
339 		pr_err("No extended regions are found\n");
340 		return -EINVAL;
341 	}
342 
343 	regs = kcalloc(nr_reg, sizeof(*regs), GFP_KERNEL);
344 	if (!regs)
345 		return -ENOMEM;
346 
347 	/*
348 	 * Create resource from extended regions provided by the hypervisor to be
349 	 * used as unused address space for Xen scratch pages.
350 	 */
351 	for (i = 0; i < nr_reg; i++) {
352 		rc = of_address_to_resource(np, i + EXT_REGION_INDEX, &regs[i]);
353 		if (rc)
354 			goto err;
355 
356 		if (max_gpaddr < regs[i].end)
357 			max_gpaddr = regs[i].end;
358 		if (min_gpaddr > regs[i].start)
359 			min_gpaddr = regs[i].start;
360 	}
361 
362 	xen_resource.start = min_gpaddr;
363 	xen_resource.end = max_gpaddr;
364 
365 	/*
366 	 * Mark holes between extended regions as unavailable. The rest of that
367 	 * address space will be available for the allocation.
368 	 */
369 	for (i = 1; i < nr_reg; i++) {
370 		resource_size_t start, end;
371 
372 		/* There is an overlap between regions */
373 		if (regs[i - 1].end + 1 > regs[i].start) {
374 			rc = -EINVAL;
375 			goto err;
376 		}
377 
378 		/* There is no hole between regions */
379 		if (regs[i - 1].end + 1 == regs[i].start)
380 			continue;
381 
382 		start = regs[i - 1].end + 1;
383 		end = regs[i].start - 1;
384 
385 		tmp_res = kzalloc(sizeof(*tmp_res), GFP_KERNEL);
386 		if (!tmp_res) {
387 			rc = -ENOMEM;
388 			goto err;
389 		}
390 
391 		tmp_res->name = "Unavailable space";
392 		tmp_res->start = start;
393 		tmp_res->end = end;
394 
395 		rc = insert_resource(&xen_resource, tmp_res);
396 		if (rc) {
397 			pr_err("Cannot insert resource %pR (%d)\n", tmp_res, rc);
398 			kfree(tmp_res);
399 			goto err;
400 		}
401 	}
402 
403 	*res = &xen_resource;
404 
405 err:
406 	kfree(regs);
407 
408 	return rc;
409 }
410 #endif
411 
412 static void __init xen_dt_guest_init(void)
413 {
414 	struct device_node *xen_node;
415 	struct resource res;
416 
417 	xen_node = of_find_compatible_node(NULL, NULL, "xen,xen");
418 	if (!xen_node) {
419 		pr_err("Xen support was detected before, but it has disappeared\n");
420 		return;
421 	}
422 
423 	xen_events_irq = irq_of_parse_and_map(xen_node, 0);
424 
425 	if (of_address_to_resource(xen_node, GRANT_TABLE_INDEX, &res)) {
426 		pr_err("Xen grant table region is not found\n");
427 		return;
428 	}
429 	xen_grant_frames = res.start;
430 }
431 
432 static int __init xen_guest_init(void)
433 {
434 	struct xen_add_to_physmap xatp;
435 	struct shared_info *shared_info_page = NULL;
436 	int rc, cpu;
437 
438 	if (!xen_domain())
439 		return 0;
440 
441 	if (!acpi_disabled)
442 		xen_acpi_guest_init();
443 	else
444 		xen_dt_guest_init();
445 
446 	if (!xen_events_irq) {
447 		pr_err("Xen event channel interrupt not found\n");
448 		return -ENODEV;
449 	}
450 
451 	/*
452 	 * The fdt parsing codes have set EFI_RUNTIME_SERVICES if Xen EFI
453 	 * parameters are found. Force enable runtime services.
454 	 */
455 	if (efi_enabled(EFI_RUNTIME_SERVICES))
456 		xen_efi_runtime_setup();
457 
458 	shared_info_page = (struct shared_info *)get_zeroed_page(GFP_KERNEL);
459 
460 	if (!shared_info_page) {
461 		pr_err("not enough memory\n");
462 		return -ENOMEM;
463 	}
464 	xatp.domid = DOMID_SELF;
465 	xatp.idx = 0;
466 	xatp.space = XENMAPSPACE_shared_info;
467 	xatp.gpfn = virt_to_gfn(shared_info_page);
468 	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
469 		BUG();
470 
471 	HYPERVISOR_shared_info = (struct shared_info *)shared_info_page;
472 
473 	/* xen_vcpu is a pointer to the vcpu_info struct in the shared_info
474 	 * page, we use it in the event channel upcall and in some pvclock
475 	 * related functions.
476 	 * The shared info contains exactly 1 CPU (the boot CPU). The guest
477 	 * is required to use VCPUOP_register_vcpu_info to place vcpu info
478 	 * for secondary CPUs as they are brought up.
479 	 * For uniformity we use VCPUOP_register_vcpu_info even on cpu0.
480 	 */
481 	xen_vcpu_info = alloc_percpu(struct vcpu_info);
482 	if (xen_vcpu_info == NULL)
483 		return -ENOMEM;
484 
485 	/* Direct vCPU id mapping for ARM guests. */
486 	for_each_possible_cpu(cpu)
487 		per_cpu(xen_vcpu_id, cpu) = cpu;
488 
489 	if (!xen_grant_frames) {
490 		xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames();
491 		rc = xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn,
492 										   &xen_auto_xlat_grant_frames.vaddr,
493 										   xen_auto_xlat_grant_frames.count);
494 	} else
495 		rc = gnttab_setup_auto_xlat_frames(xen_grant_frames);
496 	if (rc) {
497 		free_percpu(xen_vcpu_info);
498 		return rc;
499 	}
500 	gnttab_init();
501 
502 	/*
503 	 * Making sure board specific code will not set up ops for
504 	 * cpu idle and cpu freq.
505 	 */
506 	disable_cpuidle();
507 	disable_cpufreq();
508 
509 	xen_init_IRQ();
510 
511 	if (request_percpu_irq(xen_events_irq, xen_arm_callback,
512 			       "events", &xen_vcpu)) {
513 		pr_err("Error request IRQ %d\n", xen_events_irq);
514 		return -EINVAL;
515 	}
516 
517 	if (!xen_kernel_unmapped_at_usr())
518 		xen_time_setup_guest();
519 
520 	if (xen_initial_domain())
521 		pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier);
522 
523 	return cpuhp_setup_state(CPUHP_AP_ARM_XEN_STARTING,
524 				 "arm/xen:starting", xen_starting_cpu,
525 				 xen_dying_cpu);
526 }
527 early_initcall(xen_guest_init);
528 
529 static int __init xen_pm_init(void)
530 {
531 	if (!xen_domain())
532 		return -ENODEV;
533 
534 	pm_power_off = xen_power_off;
535 	register_restart_handler(&xen_restart_nb);
536 	if (!xen_initial_domain()) {
537 		struct timespec64 ts;
538 		xen_read_wallclock(&ts);
539 		do_settimeofday64(&ts);
540 	}
541 
542 	return 0;
543 }
544 late_initcall(xen_pm_init);
545 
546 
547 /* empty stubs */
548 void xen_arch_pre_suspend(void) { }
549 void xen_arch_post_suspend(int suspend_cancelled) { }
550 void xen_timer_resume(void) { }
551 void xen_arch_resume(void) { }
552 void xen_arch_suspend(void) { }
553 
554 
555 /* In the hypercall.S file. */
556 EXPORT_SYMBOL_GPL(HYPERVISOR_event_channel_op);
557 EXPORT_SYMBOL_GPL(HYPERVISOR_grant_table_op);
558 EXPORT_SYMBOL_GPL(HYPERVISOR_xen_version);
559 EXPORT_SYMBOL_GPL(HYPERVISOR_console_io);
560 EXPORT_SYMBOL_GPL(HYPERVISOR_sched_op);
561 EXPORT_SYMBOL_GPL(HYPERVISOR_hvm_op);
562 EXPORT_SYMBOL_GPL(HYPERVISOR_memory_op);
563 EXPORT_SYMBOL_GPL(HYPERVISOR_physdev_op);
564 EXPORT_SYMBOL_GPL(HYPERVISOR_vcpu_op);
565 EXPORT_SYMBOL_GPL(HYPERVISOR_platform_op_raw);
566 EXPORT_SYMBOL_GPL(HYPERVISOR_multicall);
567 EXPORT_SYMBOL_GPL(HYPERVISOR_vm_assist);
568 EXPORT_SYMBOL_GPL(HYPERVISOR_dm_op);
569 EXPORT_SYMBOL_GPL(privcmd_call);
570