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(state: CPUHP_XEN_PREPARE,
88 name: "x86/xen/guest:prepare",
89 startup: cpu_up_prepare_cb, teardown: cpu_dead_cb);
90 if (rc >= 0) {
91 rc = cpuhp_setup_state_nocalls(state: CPUHP_AP_ONLINE_DYN,
92 name: "x86/xen/guest:online",
93 startup: xen_cpu_up_online, NULL);
94 if (rc < 0)
95 cpuhp_remove_state_nocalls(state: 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 vcpuid: xen_vcpu_nr(cpu), NULL) > 0;
134
135 if (other_cpu && is_up &&
136 HYPERVISOR_vcpu_op(VCPUOP_down, vcpuid: 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, vcpuid: 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(vaddr: 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, vcpuid: xen_vcpu_nr(cpu),
198 extra_args: &info);
199 if (err)
200 panic(fmt: "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, arg: &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(name: "xenboot", idx: 0, NULL);
237 if (!boot_params.screen_info.orig_video_isVGA)
238 add_preferred_console(name: "tty", idx: 0, NULL);
239 add_preferred_console(name: "hvc", idx: 0, NULL);
240 if (boot_params.screen_info.orig_video_isVGA)
241 add_preferred_console(name: "tty", idx: 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, arg: &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(reason: 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(nh: &panic_notifier_list, nb: &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, arg: &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(cpu: num);
345}
346EXPORT_SYMBOL(xen_arch_register_cpu);
347
348void xen_arch_unregister_cpu(int num)
349{
350 arch_unregister_cpu(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

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