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
28EXPORT_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 */
37DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
38DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);
39
40/* Linux <-> Xen vCPU id mapping */
41DEFINE_PER_CPU(uint32_t, xen_vcpu_id);
42EXPORT_PER_CPU_SYMBOL(xen_vcpu_id);
43
44unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START;
45EXPORT_SYMBOL(machine_to_phys_mapping);
46unsigned long machine_to_phys_nr;
47EXPORT_SYMBOL(machine_to_phys_nr);
48
49struct start_info *xen_start_info;
50EXPORT_SYMBOL_GPL(xen_start_info);
51
52struct shared_info xen_dummy_shared_info;
53
54__read_mostly bool xen_have_vector_callback = true;
55EXPORT_SYMBOL_GPL(xen_have_vector_callback);
56
57/*
58 * NB: These need to live in .data or alike because they're used by
59 * xen_prepare_pvh() which runs before clearing the bss.
60 */
61enum xen_domain_type __ro_after_init xen_domain_type = XEN_NATIVE;
62EXPORT_SYMBOL_GPL(xen_domain_type);
63uint32_t __ro_after_init xen_start_flags;
64EXPORT_SYMBOL(xen_start_flags);
65
66/*
67 * Point at some empty memory to start with. We map the real shared_info
68 * page as soon as fixmap is up and running.
69 */
70struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info;
71
72static int xen_cpu_up_online(unsigned int cpu)
73{
74 xen_init_lock_cpu(cpu);
75 return 0;
76}
77
78int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int),
79 int (*cpu_dead_cb)(unsigned int))
80{
81 int rc;
82
83 rc = cpuhp_setup_state_nocalls(state: CPUHP_XEN_PREPARE,
84 name: "x86/xen/guest:prepare",
85 startup: cpu_up_prepare_cb, teardown: cpu_dead_cb);
86 if (rc >= 0) {
87 rc = cpuhp_setup_state_nocalls(state: CPUHP_AP_ONLINE_DYN,
88 name: "x86/xen/guest:online",
89 startup: xen_cpu_up_online, NULL);
90 if (rc < 0)
91 cpuhp_remove_state_nocalls(state: CPUHP_XEN_PREPARE);
92 }
93
94 return rc >= 0 ? 0 : rc;
95}
96
97static void xen_vcpu_setup_restore(int cpu)
98{
99 /* Any per_cpu(xen_vcpu) is stale, so reset it */
100 xen_vcpu_info_reset(cpu);
101
102 /*
103 * For PVH and PVHVM, setup online VCPUs only. The rest will
104 * be handled by hotplug.
105 */
106 if (xen_pv_domain() ||
107 (xen_hvm_domain() && cpu_online(cpu)))
108 xen_vcpu_setup(cpu);
109}
110
111/*
112 * On restore, set the vcpu placement up again.
113 * If it fails, then we're in a bad state, since
114 * we can't back out from using it...
115 */
116void xen_vcpu_restore(void)
117{
118 int cpu;
119
120 for_each_possible_cpu(cpu) {
121 bool other_cpu = (cpu != smp_processor_id());
122 bool is_up;
123
124 if (xen_vcpu_nr(cpu) == XEN_VCPU_ID_INVALID)
125 continue;
126
127 /* Only Xen 4.5 and higher support this. */
128 is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up,
129 vcpuid: xen_vcpu_nr(cpu), NULL) > 0;
130
131 if (other_cpu && is_up &&
132 HYPERVISOR_vcpu_op(VCPUOP_down, vcpuid: xen_vcpu_nr(cpu), NULL))
133 BUG();
134
135 if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock))
136 xen_setup_runstate_info(cpu);
137
138 xen_vcpu_setup_restore(cpu);
139
140 if (other_cpu && is_up &&
141 HYPERVISOR_vcpu_op(VCPUOP_up, vcpuid: xen_vcpu_nr(cpu), NULL))
142 BUG();
143 }
144}
145
146void xen_vcpu_info_reset(int cpu)
147{
148 if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) {
149 per_cpu(xen_vcpu, cpu) =
150 &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)];
151 } else {
152 /* Set to NULL so that if somebody accesses it we get an OOPS */
153 per_cpu(xen_vcpu, cpu) = NULL;
154 }
155}
156
157void xen_vcpu_setup(int cpu)
158{
159 struct vcpu_register_vcpu_info info;
160 int err;
161 struct vcpu_info *vcpup;
162
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(vaddr: 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, vcpuid: xen_vcpu_nr(cpu),
193 extra_args: &info);
194 if (err)
195 panic(fmt: "register_vcpu_info failed: cpu=%d err=%d\n", cpu, err);
196
197 per_cpu(xen_vcpu, cpu) = vcpup;
198}
199
200void __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, arg: &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 */
215bool 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
229void __init xen_add_preferred_consoles(void)
230{
231 add_preferred_console(name: "xenboot", idx: 0, NULL);
232 if (!boot_params.screen_info.orig_video_isVGA)
233 add_preferred_console(name: "tty", idx: 0, NULL);
234 add_preferred_console(name: "hvc", idx: 0, NULL);
235 if (boot_params.screen_info.orig_video_isVGA)
236 add_preferred_console(name: "tty", idx: 0, NULL);
237}
238
239void 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, arg: &r))
248 BUG();
249}
250
251static int reboot_reason = SHUTDOWN_reboot;
252static bool xen_legacy_crash;
253void xen_emergency_restart(void)
254{
255 xen_reboot(reason: reboot_reason);
256}
257
258static int
259xen_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
279static int __init parse_xen_legacy_crash(char *arg)
280{
281 xen_legacy_crash = true;
282 return 0;
283}
284early_param("xen_legacy_crash", parse_xen_legacy_crash);
285
286static struct notifier_block xen_panic_block = {
287 .notifier_call = xen_panic_event,
288 .priority = INT_MIN
289};
290
291int xen_panic_handler_init(void)
292{
293 atomic_notifier_chain_register(nh: &panic_notifier_list, nb: &xen_panic_block);
294 return 0;
295}
296
297void 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, arg: &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
337void xen_arch_register_cpu(int num)
338{
339 arch_register_cpu(cpu: num);
340}
341EXPORT_SYMBOL(xen_arch_register_cpu);
342
343void xen_arch_unregister_cpu(int num)
344{
345 arch_unregister_cpu(cpu: num);
346}
347EXPORT_SYMBOL(xen_arch_unregister_cpu);
348#endif
349

source code of linux/arch/x86/xen/enlighten.c