xref: /openbmc/linux/arch/arm/xen/enlighten.c (revision faffb083) 
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 #include <linux/virtio_anchor.h>
38 
39 #include <linux/mm.h>
40 
41 static struct start_info _xen_start_info;
42 struct start_info *xen_start_info = &_xen_start_info;
43 EXPORT_SYMBOL(xen_start_info);
44 
45 enum xen_domain_type xen_domain_type = XEN_NATIVE;
46 EXPORT_SYMBOL(xen_domain_type);
47 
48 struct shared_info xen_dummy_shared_info;
49 struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info;
50 
51 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
52 static struct vcpu_info __percpu *xen_vcpu_info;
53 
54 /* Linux <-> Xen vCPU id mapping */
55 DEFINE_PER_CPU(uint32_t, xen_vcpu_id);
56 EXPORT_PER_CPU_SYMBOL(xen_vcpu_id);
57 
58 /* These are unused until we support booting "pre-ballooned" */
59 unsigned long xen_released_pages;
60 struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
61 
62 static __read_mostly unsigned int xen_events_irq;
63 static __read_mostly phys_addr_t xen_grant_frames;
64 
65 #define GRANT_TABLE_INDEX   0
66 #define EXT_REGION_INDEX    1
67 
68 uint32_t xen_start_flags;
69 EXPORT_SYMBOL(xen_start_flags);
70 
71 int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
72 			       int nr, struct page **pages)
73 {
74 	return xen_xlate_unmap_gfn_range(vma, nr, pages);
75 }
76 EXPORT_SYMBOL_GPL(xen_unmap_domain_gfn_range);
77 
78 static void xen_read_wallclock(struct timespec64 *ts)
79 {
80 	u32 version;
81 	struct timespec64 now, ts_monotonic;
82 	struct shared_info *s = HYPERVISOR_shared_info;
83 	struct pvclock_wall_clock *wall_clock = &(s->wc);
84 
85 	/* get wallclock at system boot */
86 	do {
87 		version = wall_clock->version;
88 		rmb();		/* fetch version before time */
89 		now.tv_sec  = ((uint64_t)wall_clock->sec_hi << 32) | wall_clock->sec;
90 		now.tv_nsec = wall_clock->nsec;
91 		rmb();		/* fetch time before checking version */
92 	} while ((wall_clock->version & 1) || (version != wall_clock->version));
93 
94 	/* time since system boot */
95 	ktime_get_ts64(&ts_monotonic);
96 	*ts = timespec64_add(now, ts_monotonic);
97 }
98 
99 static int xen_pvclock_gtod_notify(struct notifier_block *nb,
100 				   unsigned long was_set, void *priv)
101 {
102 	/* Protected by the calling core code serialization */
103 	static struct timespec64 next_sync;
104 
105 	struct xen_platform_op op;
106 	struct timespec64 now, system_time;
107 	struct timekeeper *tk = priv;
108 
109 	now.tv_sec = tk->xtime_sec;
110 	now.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
111 	system_time = timespec64_add(now, tk->wall_to_monotonic);
112 
113 	/*
114 	 * We only take the expensive HV call when the clock was set
115 	 * or when the 11 minutes RTC synchronization time elapsed.
116 	 */
117 	if (!was_set && timespec64_compare(&now, &next_sync) < 0)
118 		return NOTIFY_OK;
119 
120 	op.cmd = XENPF_settime64;
121 	op.u.settime64.mbz = 0;
122 	op.u.settime64.secs = now.tv_sec;
123 	op.u.settime64.nsecs = now.tv_nsec;
124 	op.u.settime64.system_time = timespec64_to_ns(&system_time);
125 	(void)HYPERVISOR_platform_op(&op);
126 
127 	/*
128 	 * Move the next drift compensation time 11 minutes
129 	 * ahead. That's emulating the sync_cmos_clock() update for
130 	 * the hardware RTC.
131 	 */
132 	next_sync = now;
133 	next_sync.tv_sec += 11 * 60;
134 
135 	return NOTIFY_OK;
136 }
137 
138 static struct notifier_block xen_pvclock_gtod_notifier = {
139 	.notifier_call = xen_pvclock_gtod_notify,
140 };
141 
142 static int xen_starting_cpu(unsigned int cpu)
143 {
144 	struct vcpu_register_vcpu_info info;
145 	struct vcpu_info *vcpup;
146 	int err;
147 
148 	/*
149 	 * VCPUOP_register_vcpu_info cannot be called twice for the same
150 	 * vcpu, so if vcpu_info is already registered, just get out. This
151 	 * can happen with cpu-hotplug.
152 	 */
153 	if (per_cpu(xen_vcpu, cpu) != NULL)
154 		goto after_register_vcpu_info;
155 
156 	pr_info("Xen: initializing cpu%d\n", cpu);
157 	vcpup = per_cpu_ptr(xen_vcpu_info, cpu);
158 
159 	info.mfn = percpu_to_gfn(vcpup);
160 	info.offset = xen_offset_in_page(vcpup);
161 
162 	err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu),
163 				 &info);
164 	BUG_ON(err);
165 	per_cpu(xen_vcpu, cpu) = vcpup;
166 
167 	if (!xen_kernel_unmapped_at_usr())
168 		xen_setup_runstate_info(cpu);
169 
170 after_register_vcpu_info:
171 	enable_percpu_irq(xen_events_irq, 0);
172 	return 0;
173 }
174 
175 static int xen_dying_cpu(unsigned int cpu)
176 {
177 	disable_percpu_irq(xen_events_irq);
178 	return 0;
179 }
180 
181 void xen_reboot(int reason)
182 {
183 	struct sched_shutdown r = { .reason = reason };
184 	int rc;
185 
186 	rc = HYPERVISOR_sched_op(SCHEDOP_shutdown, &r);
187 	BUG_ON(rc);
188 }
189 
190 static int xen_restart(struct notifier_block *nb, unsigned long action,
191 		       void *data)
192 {
193 	xen_reboot(SHUTDOWN_reboot);
194 
195 	return NOTIFY_DONE;
196 }
197 
198 static struct notifier_block xen_restart_nb = {
199 	.notifier_call = xen_restart,
200 	.priority = 192,
201 };
202 
203 static void xen_power_off(void)
204 {
205 	xen_reboot(SHUTDOWN_poweroff);
206 }
207 
208 static irqreturn_t xen_arm_callback(int irq, void *arg)
209 {
210 	xen_hvm_evtchn_do_upcall();
211 	return IRQ_HANDLED;
212 }
213 
214 static __initdata struct {
215 	const char *compat;
216 	const char *prefix;
217 	const char *version;
218 	bool found;
219 } hyper_node = {"xen,xen", "xen,xen-", NULL, false};
220 
221 static int __init fdt_find_hyper_node(unsigned long node, const char *uname,
222 				      int depth, void *data)
223 {
224 	const void *s = NULL;
225 	int len;
226 
227 	if (depth != 1 || strcmp(uname, "hypervisor") != 0)
228 		return 0;
229 
230 	if (of_flat_dt_is_compatible(node, hyper_node.compat))
231 		hyper_node.found = true;
232 
233 	s = of_get_flat_dt_prop(node, "compatible", &len);
234 	if (strlen(hyper_node.prefix) + 3  < len &&
235 	    !strncmp(hyper_node.prefix, s, strlen(hyper_node.prefix)))
236 		hyper_node.version = s + strlen(hyper_node.prefix);
237 
238 	/*
239 	 * Check if Xen supports EFI by checking whether there is the
240 	 * "/hypervisor/uefi" node in DT. If so, runtime services are available
241 	 * through proxy functions (e.g. in case of Xen dom0 EFI implementation
242 	 * they call special hypercall which executes relevant EFI functions)
243 	 * and that is why they are always enabled.
244 	 */
245 	if (IS_ENABLED(CONFIG_XEN_EFI)) {
246 		if ((of_get_flat_dt_subnode_by_name(node, "uefi") > 0) &&
247 		    !efi_runtime_disabled())
248 			set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
249 	}
250 
251 	return 0;
252 }
253 
254 /*
255  * see Documentation/devicetree/bindings/arm/xen.txt for the
256  * documentation of the Xen Device Tree format.
257  */
258 void __init xen_early_init(void)
259 {
260 	of_scan_flat_dt(fdt_find_hyper_node, NULL);
261 	if (!hyper_node.found) {
262 		pr_debug("No Xen support\n");
263 		return;
264 	}
265 
266 	if (hyper_node.version == NULL) {
267 		pr_debug("Xen version not found\n");
268 		return;
269 	}
270 
271 	pr_info("Xen %s support found\n", hyper_node.version);
272 
273 	xen_domain_type = XEN_HVM_DOMAIN;
274 
275 	xen_setup_features();
276 
277 	if (xen_feature(XENFEAT_dom0))
278 		xen_start_flags |= SIF_INITDOMAIN|SIF_PRIVILEGED;
279 
280 	if (!console_set_on_cmdline && !xen_initial_domain())
281 		add_preferred_console("hvc", 0, NULL);
282 }
283 
284 static void __init xen_acpi_guest_init(void)
285 {
286 #ifdef CONFIG_ACPI
287 	struct xen_hvm_param a;
288 	int interrupt, trigger, polarity;
289 
290 	a.domid = DOMID_SELF;
291 	a.index = HVM_PARAM_CALLBACK_IRQ;
292 
293 	if (HYPERVISOR_hvm_op(HVMOP_get_param, &a)
294 	    || (a.value >> 56) != HVM_PARAM_CALLBACK_TYPE_PPI) {
295 		xen_events_irq = 0;
296 		return;
297 	}
298 
299 	interrupt = a.value & 0xff;
300 	trigger = ((a.value >> 8) & 0x1) ? ACPI_EDGE_SENSITIVE
301 					 : ACPI_LEVEL_SENSITIVE;
302 	polarity = ((a.value >> 8) & 0x2) ? ACPI_ACTIVE_LOW
303 					  : ACPI_ACTIVE_HIGH;
304 	xen_events_irq = acpi_register_gsi(NULL, interrupt, trigger, polarity);
305 #endif
306 }
307 
308 #ifdef CONFIG_XEN_UNPOPULATED_ALLOC
309 /*
310  * A type-less specific Xen resource which contains extended regions
311  * (unused regions of guest physical address space provided by the hypervisor).
312  */
313 static struct resource xen_resource = {
314 	.name = "Xen unused space",
315 };
316 
317 int __init arch_xen_unpopulated_init(struct resource **res)
318 {
319 	struct device_node *np;
320 	struct resource *regs, *tmp_res;
321 	uint64_t min_gpaddr = -1, max_gpaddr = 0;
322 	unsigned int i, nr_reg = 0;
323 	int rc;
324 
325 	if (!xen_domain())
326 		return -ENODEV;
327 
328 	if (!acpi_disabled)
329 		return -ENODEV;
330 
331 	np = of_find_compatible_node(NULL, NULL, "xen,xen");
332 	if (WARN_ON(!np))
333 		return -ENODEV;
334 
335 	/* Skip region 0 which is reserved for grant table space */
336 	while (of_get_address(np, nr_reg + EXT_REGION_INDEX, NULL, NULL))
337 		nr_reg++;
338 
339 	if (!nr_reg) {
340 		pr_err("No extended regions are found\n");
341 		of_node_put(np);
342 		return -EINVAL;
343 	}
344 
345 	regs = kcalloc(nr_reg, sizeof(*regs), GFP_KERNEL);
346 	if (!regs) {
347 		of_node_put(np);
348 		return -ENOMEM;
349 	}
350 
351 	/*
352 	 * Create resource from extended regions provided by the hypervisor to be
353 	 * used as unused address space for Xen scratch pages.
354 	 */
355 	for (i = 0; i < nr_reg; i++) {
356 		rc = of_address_to_resource(np, i + EXT_REGION_INDEX, &regs[i]);
357 		if (rc)
358 			goto err;
359 
360 		if (max_gpaddr < regs[i].end)
361 			max_gpaddr = regs[i].end;
362 		if (min_gpaddr > regs[i].start)
363 			min_gpaddr = regs[i].start;
364 	}
365 
366 	xen_resource.start = min_gpaddr;
367 	xen_resource.end = max_gpaddr;
368 
369 	/*
370 	 * Mark holes between extended regions as unavailable. The rest of that
371 	 * address space will be available for the allocation.
372 	 */
373 	for (i = 1; i < nr_reg; i++) {
374 		resource_size_t start, end;
375 
376 		/* There is an overlap between regions */
377 		if (regs[i - 1].end + 1 > regs[i].start) {
378 			rc = -EINVAL;
379 			goto err;
380 		}
381 
382 		/* There is no hole between regions */
383 		if (regs[i - 1].end + 1 == regs[i].start)
384 			continue;
385 
386 		start = regs[i - 1].end + 1;
387 		end = regs[i].start - 1;
388 
389 		tmp_res = kzalloc(sizeof(*tmp_res), GFP_KERNEL);
390 		if (!tmp_res) {
391 			rc = -ENOMEM;
392 			goto err;
393 		}
394 
395 		tmp_res->name = "Unavailable space";
396 		tmp_res->start = start;
397 		tmp_res->end = end;
398 
399 		rc = insert_resource(&xen_resource, tmp_res);
400 		if (rc) {
401 			pr_err("Cannot insert resource %pR (%d)\n", tmp_res, rc);
402 			kfree(tmp_res);
403 			goto err;
404 		}
405 	}
406 
407 	*res = &xen_resource;
408 
409 err:
410 	of_node_put(np);
411 	kfree(regs);
412 	return rc;
413 }
414 #endif
415 
416 static void __init xen_dt_guest_init(void)
417 {
418 	struct device_node *xen_node;
419 	struct resource res;
420 
421 	xen_node = of_find_compatible_node(NULL, NULL, "xen,xen");
422 	if (!xen_node) {
423 		pr_err("Xen support was detected before, but it has disappeared\n");
424 		return;
425 	}
426 
427 	xen_events_irq = irq_of_parse_and_map(xen_node, 0);
428 
429 	if (of_address_to_resource(xen_node, GRANT_TABLE_INDEX, &res)) {
430 		pr_err("Xen grant table region is not found\n");
431 		of_node_put(xen_node);
432 		return;
433 	}
434 	of_node_put(xen_node);
435 	xen_grant_frames = res.start;
436 }
437 
438 static int __init xen_guest_init(void)
439 {
440 	struct xen_add_to_physmap xatp;
441 	struct shared_info *shared_info_page = NULL;
442 	int rc, cpu;
443 
444 	if (!xen_domain())
445 		return 0;
446 
447 	if (IS_ENABLED(CONFIG_XEN_VIRTIO))
448 		virtio_set_mem_acc_cb(xen_virtio_restricted_mem_acc);
449 
450 	if (!acpi_disabled)
451 		xen_acpi_guest_init();
452 	else
453 		xen_dt_guest_init();
454 
455 	if (!xen_events_irq) {
456 		pr_err("Xen event channel interrupt not found\n");
457 		return -ENODEV;
458 	}
459 
460 	/*
461 	 * The fdt parsing codes have set EFI_RUNTIME_SERVICES if Xen EFI
462 	 * parameters are found. Force enable runtime services.
463 	 */
464 	if (efi_enabled(EFI_RUNTIME_SERVICES))
465 		xen_efi_runtime_setup();
466 
467 	shared_info_page = (struct shared_info *)get_zeroed_page(GFP_KERNEL);
468 
469 	if (!shared_info_page) {
470 		pr_err("not enough memory\n");
471 		return -ENOMEM;
472 	}
473 	xatp.domid = DOMID_SELF;
474 	xatp.idx = 0;
475 	xatp.space = XENMAPSPACE_shared_info;
476 	xatp.gpfn = virt_to_gfn(shared_info_page);
477 	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
478 		BUG();
479 
480 	HYPERVISOR_shared_info = (struct shared_info *)shared_info_page;
481 
482 	/* xen_vcpu is a pointer to the vcpu_info struct in the shared_info
483 	 * page, we use it in the event channel upcall and in some pvclock
484 	 * related functions.
485 	 * The shared info contains exactly 1 CPU (the boot CPU). The guest
486 	 * is required to use VCPUOP_register_vcpu_info to place vcpu info
487 	 * for secondary CPUs as they are brought up.
488 	 * For uniformity we use VCPUOP_register_vcpu_info even on cpu0.
489 	 */
490 	xen_vcpu_info = alloc_percpu(struct vcpu_info);
491 	if (xen_vcpu_info == NULL)
492 		return -ENOMEM;
493 
494 	/* Direct vCPU id mapping for ARM guests. */
495 	for_each_possible_cpu(cpu)
496 		per_cpu(xen_vcpu_id, cpu) = cpu;
497 
498 	if (!xen_grant_frames) {
499 		xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames();
500 		rc = xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn,
501 										   &xen_auto_xlat_grant_frames.vaddr,
502 										   xen_auto_xlat_grant_frames.count);
503 	} else
504 		rc = gnttab_setup_auto_xlat_frames(xen_grant_frames);
505 	if (rc) {
506 		free_percpu(xen_vcpu_info);
507 		return rc;
508 	}
509 	gnttab_init();
510 
511 	/*
512 	 * Making sure board specific code will not set up ops for
513 	 * cpu idle and cpu freq.
514 	 */
515 	disable_cpuidle();
516 	disable_cpufreq();
517 
518 	xen_init_IRQ();
519 
520 	if (request_percpu_irq(xen_events_irq, xen_arm_callback,
521 			       "events", &xen_vcpu)) {
522 		pr_err("Error request IRQ %d\n", xen_events_irq);
523 		return -EINVAL;
524 	}
525 
526 	if (!xen_kernel_unmapped_at_usr())
527 		xen_time_setup_guest();
528 
529 	if (xen_initial_domain())
530 		pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier);
531 
532 	return cpuhp_setup_state(CPUHP_AP_ARM_XEN_STARTING,
533 				 "arm/xen:starting", xen_starting_cpu,
534 				 xen_dying_cpu);
535 }
536 early_initcall(xen_guest_init);
537 
538 static int __init xen_pm_init(void)
539 {
540 	if (!xen_domain())
541 		return -ENODEV;
542 
543 	pm_power_off = xen_power_off;
544 	register_restart_handler(&xen_restart_nb);
545 	if (!xen_initial_domain()) {
546 		struct timespec64 ts;
547 		xen_read_wallclock(&ts);
548 		do_settimeofday64(&ts);
549 	}
550 
551 	return 0;
552 }
553 late_initcall(xen_pm_init);
554 
555 
556 /* empty stubs */
557 void xen_arch_pre_suspend(void) { }
558 void xen_arch_post_suspend(int suspend_cancelled) { }
559 void xen_timer_resume(void) { }
560 void xen_arch_resume(void) { }
561 void xen_arch_suspend(void) { }
562 
563 
564 /* In the hypercall.S file. */
565 EXPORT_SYMBOL_GPL(HYPERVISOR_event_channel_op);
566 EXPORT_SYMBOL_GPL(HYPERVISOR_grant_table_op);
567 EXPORT_SYMBOL_GPL(HYPERVISOR_xen_version);
568 EXPORT_SYMBOL_GPL(HYPERVISOR_console_io);
569 EXPORT_SYMBOL_GPL(HYPERVISOR_sched_op);
570 EXPORT_SYMBOL_GPL(HYPERVISOR_hvm_op);
571 EXPORT_SYMBOL_GPL(HYPERVISOR_memory_op);
572 EXPORT_SYMBOL_GPL(HYPERVISOR_physdev_op);
573 EXPORT_SYMBOL_GPL(HYPERVISOR_vcpu_op);
574 EXPORT_SYMBOL_GPL(HYPERVISOR_platform_op_raw);
575 EXPORT_SYMBOL_GPL(HYPERVISOR_multicall);
576 EXPORT_SYMBOL_GPL(HYPERVISOR_vm_assist);
577 EXPORT_SYMBOL_GPL(HYPERVISOR_dm_op);
578 EXPORT_SYMBOL_GPL(privcmd_call);
579