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