1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <linux/console.h>
4 #include <linux/cpu.h>
5 #include <linux/kexec.h>
6 #include <linux/memblock.h>
7 #include <linux/slab.h>
8 #include <linux/panic_notifier.h>
9
10 #include <xen/xen.h>
11 #include <xen/features.h>
12 #include <xen/interface/sched.h>
13 #include <xen/interface/version.h>
14 #include <xen/page.h>
15
16 #include <asm/xen/hypercall.h>
17 #include <asm/xen/hypervisor.h>
18 #include <asm/cpu.h>
19 #include <asm/e820/api.h>
20 #include <asm/setup.h>
21
22 #include "xen-ops.h"
23
24 EXPORT_SYMBOL_GPL(hypercall_page);
25
26 /*
27 * Pointer to the xen_vcpu_info structure or
28 * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info
29 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info
30 * but during boot it is switched to point to xen_vcpu_info.
31 * The pointer is used in xen_evtchn_do_upcall to acknowledge pending events.
32 * Make sure that xen_vcpu_info doesn't cross a page boundary by making it
33 * cache-line aligned (the struct is guaranteed to have a size of 64 bytes,
34 * which matches the cache line size of 64-bit x86 processors).
35 */
36 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
37 DEFINE_PER_CPU_ALIGNED(struct vcpu_info, xen_vcpu_info);
38
39 /* Linux <-> Xen vCPU id mapping */
40 DEFINE_PER_CPU(uint32_t, xen_vcpu_id);
41 EXPORT_PER_CPU_SYMBOL(xen_vcpu_id);
42
43 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START;
44 EXPORT_SYMBOL(machine_to_phys_mapping);
45 unsigned long machine_to_phys_nr;
46 EXPORT_SYMBOL(machine_to_phys_nr);
47
48 struct start_info *xen_start_info;
49 EXPORT_SYMBOL_GPL(xen_start_info);
50
51 struct shared_info xen_dummy_shared_info;
52
53 __read_mostly bool xen_have_vector_callback = true;
54 EXPORT_SYMBOL_GPL(xen_have_vector_callback);
55
56 /*
57 * NB: These need to live in .data or alike because they're used by
58 * xen_prepare_pvh() which runs before clearing the bss.
59 */
60 enum xen_domain_type __ro_after_init xen_domain_type = XEN_NATIVE;
61 EXPORT_SYMBOL_GPL(xen_domain_type);
62 uint32_t __ro_after_init xen_start_flags;
63 EXPORT_SYMBOL(xen_start_flags);
64
65 /*
66 * Point at some empty memory to start with. We map the real shared_info
67 * page as soon as fixmap is up and running.
68 */
69 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info;
70
71 static int xen_cpu_up_online(unsigned int cpu)
72 {
73 xen_init_lock_cpu(cpu);
74 return 0;
75 }
76
77 int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int),
78 int (*cpu_dead_cb)(unsigned int))
79 {
80 int rc;
81
82 rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE,
83 "x86/xen/guest:prepare",
84 cpu_up_prepare_cb, cpu_dead_cb);
85 if (rc >= 0) {
86 rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
87 "x86/xen/guest:online",
88 xen_cpu_up_online, NULL);
89 if (rc < 0)
90 cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE);
91 }
92
93 return rc >= 0 ? 0 : rc;
94 }
95
96 static void xen_vcpu_setup_restore(int cpu)
97 {
98 /* Any per_cpu(xen_vcpu) is stale, so reset it */
99 xen_vcpu_info_reset(cpu);
100
101 /*
102 * For PVH and PVHVM, setup online VCPUs only. The rest will
103 * be handled by hotplug.
104 */
105 if (xen_pv_domain() ||
106 (xen_hvm_domain() && cpu_online(cpu)))
107 xen_vcpu_setup(cpu);
108 }
109
110 /*
111 * On restore, set the vcpu placement up again.
112 * If it fails, then we're in a bad state, since
113 * we can't back out from using it...
114 */
115 void xen_vcpu_restore(void)
116 {
117 int cpu;
118
119 for_each_possible_cpu(cpu) {
120 bool other_cpu = (cpu != smp_processor_id());
121 bool is_up;
122
123 if (xen_vcpu_nr(cpu) == XEN_VCPU_ID_INVALID)
124 continue;
125
126 /* Only Xen 4.5 and higher support this. */
127 is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up,
128 xen_vcpu_nr(cpu), NULL) > 0;
129
130 if (other_cpu && is_up &&
131 HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL))
132 BUG();
133
134 if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock))
135 xen_setup_runstate_info(cpu);
136
137 xen_vcpu_setup_restore(cpu);
138
139 if (other_cpu && is_up &&
140 HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL))
141 BUG();
142 }
143 }
144
145 void xen_vcpu_info_reset(int cpu)
146 {
147 if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) {
148 per_cpu(xen_vcpu, cpu) =
149 &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)];
150 } else {
151 /* Set to NULL so that if somebody accesses it we get an OOPS */
152 per_cpu(xen_vcpu, cpu) = NULL;
153 }
154 }
155
156 void xen_vcpu_setup(int cpu)
157 {
158 struct vcpu_register_vcpu_info info;
159 int err;
160 struct vcpu_info *vcpup;
161
162 BUILD_BUG_ON(sizeof(*vcpup) > SMP_CACHE_BYTES);
163 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
164
165 /*
166 * This path is called on PVHVM at bootup (xen_hvm_smp_prepare_boot_cpu)
167 * and at restore (xen_vcpu_restore). Also called for hotplugged
168 * VCPUs (cpu_init -> xen_hvm_cpu_prepare_hvm).
169 * However, the hypercall can only be done once (see below) so if a VCPU
170 * is offlined and comes back online then let's not redo the hypercall.
171 *
172 * For PV it is called during restore (xen_vcpu_restore) and bootup
173 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not
174 * use this function.
175 */
176 if (xen_hvm_domain()) {
177 if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu))
178 return;
179 }
180
181 vcpup = &per_cpu(xen_vcpu_info, cpu);
182 info.mfn = arbitrary_virt_to_mfn(vcpup);
183 info.offset = offset_in_page(vcpup);
184
185 /*
186 * N.B. This hypercall can _only_ be called once per CPU.
187 * Subsequent calls will error out with -EINVAL. This is due to
188 * the fact that hypervisor has no unregister variant and this
189 * hypercall does not allow to over-write info.mfn and
190 * info.offset.
191 */
192 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu),
193 &info);
194 if (err)
195 panic("register_vcpu_info failed: cpu=%d err=%d\n", cpu, err);
196
197 per_cpu(xen_vcpu, cpu) = vcpup;
198 }
199
200 void __init xen_banner(void)
201 {
202 unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
203 struct xen_extraversion extra;
204
205 HYPERVISOR_xen_version(XENVER_extraversion, &extra);
206
207 pr_info("Booting kernel on %s\n", pv_info.name);
208 pr_info("Xen version: %u.%u%s%s\n",
209 version >> 16, version & 0xffff, extra.extraversion,
210 xen_feature(XENFEAT_mmu_pt_update_preserve_ad)
211 ? " (preserve-AD)" : "");
212 }
213
214 /* Check if running on Xen version (major, minor) or later */
215 bool xen_running_on_version_or_later(unsigned int major, unsigned int minor)
216 {
217 unsigned int version;
218
219 if (!xen_domain())
220 return false;
221
222 version = HYPERVISOR_xen_version(XENVER_version, NULL);
223 if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) ||
224 ((version >> 16) > major))
225 return true;
226 return false;
227 }
228
229 void __init xen_add_preferred_consoles(void)
230 {
231 add_preferred_console("xenboot", 0, NULL);
232 if (!boot_params.screen_info.orig_video_isVGA)
233 add_preferred_console("tty", 0, NULL);
234 add_preferred_console("hvc", 0, NULL);
235 if (boot_params.screen_info.orig_video_isVGA)
236 add_preferred_console("tty", 0, NULL);
237 }
238
239 void xen_reboot(int reason)
240 {
241 struct sched_shutdown r = { .reason = reason };
242 int cpu;
243
244 for_each_online_cpu(cpu)
245 xen_pmu_finish(cpu);
246
247 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
248 BUG();
249 }
250
251 static int reboot_reason = SHUTDOWN_reboot;
252 static bool xen_legacy_crash;
253 void xen_emergency_restart(void)
254 {
255 xen_reboot(reboot_reason);
256 }
257
258 static int
259 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr)
260 {
261 if (!kexec_crash_loaded()) {
262 if (xen_legacy_crash)
263 xen_reboot(SHUTDOWN_crash);
264
265 reboot_reason = SHUTDOWN_crash;
266
267 /*
268 * If panic_timeout==0 then we are supposed to wait forever.
269 * However, to preserve original dom0 behavior we have to drop
270 * into hypervisor. (domU behavior is controlled by its
271 * config file)
272 */
273 if (panic_timeout == 0)
274 panic_timeout = -1;
275 }
276 return NOTIFY_DONE;
277 }
278
279 static int __init parse_xen_legacy_crash(char *arg)
280 {
281 xen_legacy_crash = true;
282 return 0;
283 }
284 early_param("xen_legacy_crash", parse_xen_legacy_crash);
285
286 static struct notifier_block xen_panic_block = {
287 .notifier_call = xen_panic_event,
288 .priority = INT_MIN
289 };
290
291 int xen_panic_handler_init(void)
292 {
293 atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block);
294 return 0;
295 }
296
297 void xen_pin_vcpu(int cpu)
298 {
299 static bool disable_pinning;
300 struct sched_pin_override pin_override;
301 int ret;
302
303 if (disable_pinning)
304 return;
305
306 pin_override.pcpu = cpu;
307 ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override);
308
309 /* Ignore errors when removing override. */
310 if (cpu < 0)
311 return;
312
313 switch (ret) {
314 case -ENOSYS:
315 pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n",
316 cpu);
317 disable_pinning = true;
318 break;
319 case -EPERM:
320 WARN(1, "Trying to pin vcpu without having privilege to do so\n");
321 disable_pinning = true;
322 break;
323 case -EINVAL:
324 case -EBUSY:
325 pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n",
326 cpu);
327 break;
328 case 0:
329 break;
330 default:
331 WARN(1, "rc %d while trying to pin vcpu\n", ret);
332 disable_pinning = true;
333 }
334 }
335
336 #ifdef CONFIG_HOTPLUG_CPU
337 void xen_arch_register_cpu(int num)
338 {
339 arch_register_cpu(num);
340 }
341 EXPORT_SYMBOL(xen_arch_register_cpu);
342
343 void xen_arch_unregister_cpu(int num)
344 {
345 arch_unregister_cpu(num);
346 }
347 EXPORT_SYMBOL(xen_arch_unregister_cpu);
348 #endif
349
350 /* Amount of extra memory space we add to the e820 ranges */
351 struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
352
353 void __init xen_add_extra_mem(unsigned long start_pfn, unsigned long n_pfns)
354 {
355 unsigned int i;
356
357 /*
358 * No need to check for zero size, should happen rarely and will only
359 * write a new entry regarded to be unused due to zero size.
360 */
361 for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
362 /* Add new region. */
363 if (xen_extra_mem[i].n_pfns == 0) {
364 xen_extra_mem[i].start_pfn = start_pfn;
365 xen_extra_mem[i].n_pfns = n_pfns;
366 break;
367 }
368 /* Append to existing region. */
369 if (xen_extra_mem[i].start_pfn + xen_extra_mem[i].n_pfns ==
370 start_pfn) {
371 xen_extra_mem[i].n_pfns += n_pfns;
372 break;
373 }
374 }
375 if (i == XEN_EXTRA_MEM_MAX_REGIONS)
376 printk(KERN_WARNING "Warning: not enough extra memory regions\n");
377
378 memblock_reserve(PFN_PHYS(start_pfn), PFN_PHYS(n_pfns));
379 }
380
381 #ifdef CONFIG_XEN_UNPOPULATED_ALLOC
382 int __init arch_xen_unpopulated_init(struct resource **res)
383 {
384 unsigned int i;
385
386 if (!xen_domain())
387 return -ENODEV;
388
389 /* Must be set strictly before calling xen_free_unpopulated_pages(). */
390 *res = &iomem_resource;
391
392 /*
393 * Initialize with pages from the extra memory regions (see
394 * arch/x86/xen/setup.c).
395 */
396 for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
397 unsigned int j;
398
399 for (j = 0; j < xen_extra_mem[i].n_pfns; j++) {
400 struct page *pg =
401 pfn_to_page(xen_extra_mem[i].start_pfn + j);
402
403 xen_free_unpopulated_pages(1, &pg);
404 }
405
406 /* Zero so region is not also added to the balloon driver. */
407 xen_extra_mem[i].n_pfns = 0;
408 }
409
410 return 0;
411 }
412 #endif
413
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