1// SPDX-License-Identifier: GPL-2.0
2
3#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
4#include <linux/memblock.h>
5#endif
6#include <linux/console.h>
7#include <linux/cpu.h>
8#include <linux/kexec.h>
9#include <linux/memblock.h>
10#include <linux/slab.h>
11#include <linux/panic_notifier.h>
12
13#include <xen/xen.h>
14#include <xen/features.h>
15#include <xen/interface/sched.h>
16#include <xen/interface/version.h>
17#include <xen/page.h>
18
19#include <asm/xen/hypercall.h>
20#include <asm/xen/hypervisor.h>
21#include <asm/cpu.h>
22#include <asm/e820/api.h>
23#include <asm/setup.h>
24
25#include "xen-ops.h"
26#include "smp.h"
27#include "pmu.h"
28
29EXPORT_SYMBOL_GPL(hypercall_page);
30
31/*
32 * Pointer to the xen_vcpu_info structure or
33 * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info
34 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info
35 * but during boot it is switched to point to xen_vcpu_info.
36 * The pointer is used in xen_evtchn_do_upcall to acknowledge pending events.
37 * Make sure that xen_vcpu_info doesn't cross a page boundary by making it
38 * cache-line aligned (the struct is guaranteed to have a size of 64 bytes,
39 * which matches the cache line size of 64-bit x86 processors).
40 */
41DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
42DEFINE_PER_CPU_ALIGNED(struct vcpu_info, xen_vcpu_info);
43
44/* Linux <-> Xen vCPU id mapping */
45DEFINE_PER_CPU(uint32_t, xen_vcpu_id);
46EXPORT_PER_CPU_SYMBOL(xen_vcpu_id);
47
48unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START;
49EXPORT_SYMBOL(machine_to_phys_mapping);
50unsigned long  machine_to_phys_nr;
51EXPORT_SYMBOL(machine_to_phys_nr);
52
53struct start_info *xen_start_info;
54EXPORT_SYMBOL_GPL(xen_start_info);
55
56struct shared_info xen_dummy_shared_info;
57
58__read_mostly bool xen_have_vector_callback = true;
59EXPORT_SYMBOL_GPL(xen_have_vector_callback);
60
61/*
62 * NB: These need to live in .data or alike because they're used by
63 * xen_prepare_pvh() which runs before clearing the bss.
64 */
65enum xen_domain_type __ro_after_init xen_domain_type = XEN_NATIVE;
66EXPORT_SYMBOL_GPL(xen_domain_type);
67uint32_t __ro_after_init xen_start_flags;
68EXPORT_SYMBOL(xen_start_flags);
69
70/*
71 * Point at some empty memory to start with. We map the real shared_info
72 * page as soon as fixmap is up and running.
73 */
74struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info;
75
76static int xen_cpu_up_online(unsigned int cpu)
77{
78	xen_init_lock_cpu(cpu);
79	return 0;
80}
81
82int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int),
83		    int (*cpu_dead_cb)(unsigned int))
84{
85	int rc;
86
87	rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE,
88				       "x86/xen/guest:prepare",
89				       cpu_up_prepare_cb, cpu_dead_cb);
90	if (rc >= 0) {
91		rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
92					       "x86/xen/guest:online",
93					       xen_cpu_up_online, NULL);
94		if (rc < 0)
95			cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE);
96	}
97
98	return rc >= 0 ? 0 : rc;
99}
100
101static void xen_vcpu_setup_restore(int cpu)
102{
103	/* Any per_cpu(xen_vcpu) is stale, so reset it */
104	xen_vcpu_info_reset(cpu);
105
106	/*
107	 * For PVH and PVHVM, setup online VCPUs only. The rest will
108	 * be handled by hotplug.
109	 */
110	if (xen_pv_domain() ||
111	    (xen_hvm_domain() && cpu_online(cpu)))
112		xen_vcpu_setup(cpu);
113}
114
115/*
116 * On restore, set the vcpu placement up again.
117 * If it fails, then we're in a bad state, since
118 * we can't back out from using it...
119 */
120void xen_vcpu_restore(void)
121{
122	int cpu;
123
124	for_each_possible_cpu(cpu) {
125		bool other_cpu = (cpu != smp_processor_id());
126		bool is_up;
127
128		if (xen_vcpu_nr(cpu) == XEN_VCPU_ID_INVALID)
129			continue;
130
131		/* Only Xen 4.5 and higher support this. */
132		is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up,
133					   xen_vcpu_nr(cpu), NULL) > 0;
134
135		if (other_cpu && is_up &&
136		    HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL))
137			BUG();
138
139		if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock))
140			xen_setup_runstate_info(cpu);
141
142		xen_vcpu_setup_restore(cpu);
143
144		if (other_cpu && is_up &&
145		    HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL))
146			BUG();
147	}
148}
149
150void xen_vcpu_info_reset(int cpu)
151{
152	if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) {
153		per_cpu(xen_vcpu, cpu) =
154			&HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)];
155	} else {
156		/* Set to NULL so that if somebody accesses it we get an OOPS */
157		per_cpu(xen_vcpu, cpu) = NULL;
158	}
159}
160
161void xen_vcpu_setup(int cpu)
162{
163	struct vcpu_register_vcpu_info info;
164	int err;
165	struct vcpu_info *vcpup;
166
167	BUILD_BUG_ON(sizeof(*vcpup) > SMP_CACHE_BYTES);
168	BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
169
170	/*
171	 * This path is called on PVHVM at bootup (xen_hvm_smp_prepare_boot_cpu)
172	 * and at restore (xen_vcpu_restore). Also called for hotplugged
173	 * VCPUs (cpu_init -> xen_hvm_cpu_prepare_hvm).
174	 * However, the hypercall can only be done once (see below) so if a VCPU
175	 * is offlined and comes back online then let's not redo the hypercall.
176	 *
177	 * For PV it is called during restore (xen_vcpu_restore) and bootup
178	 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not
179	 * use this function.
180	 */
181	if (xen_hvm_domain()) {
182		if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu))
183			return;
184	}
185
186	vcpup = &per_cpu(xen_vcpu_info, cpu);
187	info.mfn = arbitrary_virt_to_mfn(vcpup);
188	info.offset = offset_in_page(vcpup);
189
190	/*
191	 * N.B. This hypercall can _only_ be called once per CPU.
192	 * Subsequent calls will error out with -EINVAL. This is due to
193	 * the fact that hypervisor has no unregister variant and this
194	 * hypercall does not allow to over-write info.mfn and
195	 * info.offset.
196	 */
197	err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu),
198				 &info);
199	if (err)
200		panic("register_vcpu_info failed: cpu=%d err=%d\n", cpu, err);
201
202	per_cpu(xen_vcpu, cpu) = vcpup;
203}
204
205void __init xen_banner(void)
206{
207	unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
208	struct xen_extraversion extra;
209
210	HYPERVISOR_xen_version(XENVER_extraversion, &extra);
211
212	pr_info("Booting kernel on %s\n", pv_info.name);
213	pr_info("Xen version: %u.%u%s%s\n",
214		version >> 16, version & 0xffff, extra.extraversion,
215		xen_feature(XENFEAT_mmu_pt_update_preserve_ad)
216		? " (preserve-AD)" : "");
217}
218
219/* Check if running on Xen version (major, minor) or later */
220bool xen_running_on_version_or_later(unsigned int major, unsigned int minor)
221{
222	unsigned int version;
223
224	if (!xen_domain())
225		return false;
226
227	version = HYPERVISOR_xen_version(XENVER_version, NULL);
228	if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) ||
229		((version >> 16) > major))
230		return true;
231	return false;
232}
233
234void __init xen_add_preferred_consoles(void)
235{
236	add_preferred_console("xenboot", 0, NULL);
237	if (!boot_params.screen_info.orig_video_isVGA)
238		add_preferred_console("tty", 0, NULL);
239	add_preferred_console("hvc", 0, NULL);
240	if (boot_params.screen_info.orig_video_isVGA)
241		add_preferred_console("tty", 0, NULL);
242}
243
244void xen_reboot(int reason)
245{
246	struct sched_shutdown r = { .reason = reason };
247	int cpu;
248
249	for_each_online_cpu(cpu)
250		xen_pmu_finish(cpu);
251
252	if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
253		BUG();
254}
255
256static int reboot_reason = SHUTDOWN_reboot;
257static bool xen_legacy_crash;
258void xen_emergency_restart(void)
259{
260	xen_reboot(reboot_reason);
261}
262
263static int
264xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr)
265{
266	if (!kexec_crash_loaded()) {
267		if (xen_legacy_crash)
268			xen_reboot(SHUTDOWN_crash);
269
270		reboot_reason = SHUTDOWN_crash;
271
272		/*
273		 * If panic_timeout==0 then we are supposed to wait forever.
274		 * However, to preserve original dom0 behavior we have to drop
275		 * into hypervisor. (domU behavior is controlled by its
276		 * config file)
277		 */
278		if (panic_timeout == 0)
279			panic_timeout = -1;
280	}
281	return NOTIFY_DONE;
282}
283
284static int __init parse_xen_legacy_crash(char *arg)
285{
286	xen_legacy_crash = true;
287	return 0;
288}
289early_param("xen_legacy_crash", parse_xen_legacy_crash);
290
291static struct notifier_block xen_panic_block = {
292	.notifier_call = xen_panic_event,
293	.priority = INT_MIN
294};
295
296int xen_panic_handler_init(void)
297{
298	atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block);
299	return 0;
300}
301
302void xen_pin_vcpu(int cpu)
303{
304	static bool disable_pinning;
305	struct sched_pin_override pin_override;
306	int ret;
307
308	if (disable_pinning)
309		return;
310
311	pin_override.pcpu = cpu;
312	ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override);
313
314	/* Ignore errors when removing override. */
315	if (cpu < 0)
316		return;
317
318	switch (ret) {
319	case -ENOSYS:
320		pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n",
321			cpu);
322		disable_pinning = true;
323		break;
324	case -EPERM:
325		WARN(1, "Trying to pin vcpu without having privilege to do so\n");
326		disable_pinning = true;
327		break;
328	case -EINVAL:
329	case -EBUSY:
330		pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n",
331			cpu);
332		break;
333	case 0:
334		break;
335	default:
336		WARN(1, "rc %d while trying to pin vcpu\n", ret);
337		disable_pinning = true;
338	}
339}
340
341#ifdef CONFIG_HOTPLUG_CPU
342void xen_arch_register_cpu(int num)
343{
344	arch_register_cpu(num);
345}
346EXPORT_SYMBOL(xen_arch_register_cpu);
347
348void xen_arch_unregister_cpu(int num)
349{
350	arch_unregister_cpu(num);
351}
352EXPORT_SYMBOL(xen_arch_unregister_cpu);
353#endif
354
355/* Amount of extra memory space we add to the e820 ranges */
356struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
357
358void __init xen_add_extra_mem(unsigned long start_pfn, unsigned long n_pfns)
359{
360	unsigned int i;
361
362	/*
363	 * No need to check for zero size, should happen rarely and will only
364	 * write a new entry regarded to be unused due to zero size.
365	 */
366	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
367		/* Add new region. */
368		if (xen_extra_mem[i].n_pfns == 0) {
369			xen_extra_mem[i].start_pfn = start_pfn;
370			xen_extra_mem[i].n_pfns = n_pfns;
371			break;
372		}
373		/* Append to existing region. */
374		if (xen_extra_mem[i].start_pfn + xen_extra_mem[i].n_pfns ==
375		    start_pfn) {
376			xen_extra_mem[i].n_pfns += n_pfns;
377			break;
378		}
379	}
380	if (i == XEN_EXTRA_MEM_MAX_REGIONS)
381		printk(KERN_WARNING "Warning: not enough extra memory regions\n");
382
383	memblock_reserve(PFN_PHYS(start_pfn), PFN_PHYS(n_pfns));
384}
385