1#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
2#include <linux/bootmem.h>
3#endif
4#include <linux/cpu.h>
5#include <linux/kexec.h>
6
7#include <xen/features.h>
8#include <xen/page.h>
9#include <xen/interface/memory.h>
10
11#include <asm/xen/hypercall.h>
12#include <asm/xen/hypervisor.h>
13#include <asm/cpu.h>
14#include <asm/e820/api.h>
15
16#include "xen-ops.h"
17#include "smp.h"
18#include "pmu.h"
19
20EXPORT_SYMBOL_GPL(hypercall_page);
21
22/*
23 * Pointer to the xen_vcpu_info structure or
24 * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info
25 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info
26 * but if the hypervisor supports VCPUOP_register_vcpu_info then it can point
27 * to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to
28 * acknowledge pending events.
29 * Also more subtly it is used by the patched version of irq enable/disable
30 * e.g. xen_irq_enable_direct and xen_iret in PV mode.
31 *
32 * The desire to be able to do those mask/unmask operations as a single
33 * instruction by using the per-cpu offset held in %gs is the real reason
34 * vcpu info is in a per-cpu pointer and the original reason for this
35 * hypercall.
36 *
37 */
38DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
39
40/*
41 * Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info
42 * hypercall. This can be used both in PV and PVHVM mode. The structure
43 * overrides the default per_cpu(xen_vcpu, cpu) value.
44 */
45DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);
46
47/* Linux <-> Xen vCPU id mapping */
48DEFINE_PER_CPU(uint32_t, xen_vcpu_id);
49EXPORT_PER_CPU_SYMBOL(xen_vcpu_id);
50
51enum xen_domain_type xen_domain_type = XEN_NATIVE;
52EXPORT_SYMBOL_GPL(xen_domain_type);
53
54unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START;
55EXPORT_SYMBOL(machine_to_phys_mapping);
56unsigned long machine_to_phys_nr;
57EXPORT_SYMBOL(machine_to_phys_nr);
58
59struct start_info *xen_start_info;
60EXPORT_SYMBOL_GPL(xen_start_info);
61
62struct shared_info xen_dummy_shared_info;
63
64__read_mostly int xen_have_vector_callback;
65EXPORT_SYMBOL_GPL(xen_have_vector_callback);
66
67/*
68 * Point at some empty memory to start with. We map the real shared_info
69 * page as soon as fixmap is up and running.
70 */
71struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info;
72
73/*
74 * Flag to determine whether vcpu info placement is available on all
75 * VCPUs. We assume it is to start with, and then set it to zero on
76 * the first failure. This is because it can succeed on some VCPUs
77 * and not others, since it can involve hypervisor memory allocation,
78 * or because the guest failed to guarantee all the appropriate
79 * constraints on all VCPUs (ie buffer can't cross a page boundary).
80 *
81 * Note that any particular CPU may be using a placed vcpu structure,
82 * but we can only optimise if the all are.
83 *
84 * 0: not available, 1: available
85 */
86int xen_have_vcpu_info_placement = 1;
87
88static int xen_cpu_up_online(unsigned int cpu)
89{
90 xen_init_lock_cpu(cpu);
91 return 0;
92}
93
94int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int),
95 int (*cpu_dead_cb)(unsigned int))
96{
97 int rc;
98
99 rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE,
100 "x86/xen/guest:prepare",
101 cpu_up_prepare_cb, cpu_dead_cb);
102 if (rc >= 0) {
103 rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
104 "x86/xen/guest:online",
105 xen_cpu_up_online, NULL);
106 if (rc < 0)
107 cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE);
108 }
109
110 return rc >= 0 ? 0 : rc;
111}
112
113static int xen_vcpu_setup_restore(int cpu)
114{
115 int rc = 0;
116
117 /* Any per_cpu(xen_vcpu) is stale, so reset it */
118 xen_vcpu_info_reset(cpu);
119
120 /*
121 * For PVH and PVHVM, setup online VCPUs only. The rest will
122 * be handled by hotplug.
123 */
124 if (xen_pv_domain() ||
125 (xen_hvm_domain() && cpu_online(cpu))) {
126 rc = xen_vcpu_setup(cpu);
127 }
128
129 return rc;
130}
131
132/*
133 * On restore, set the vcpu placement up again.
134 * If it fails, then we're in a bad state, since
135 * we can't back out from using it...
136 */
137void xen_vcpu_restore(void)
138{
139 int cpu, rc;
140
141 for_each_possible_cpu(cpu) {
142 bool other_cpu = (cpu != smp_processor_id());
143 bool is_up;
144
145 if (xen_vcpu_nr(cpu) == XEN_VCPU_ID_INVALID)
146 continue;
147
148 /* Only Xen 4.5 and higher support this. */
149 is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up,
150 xen_vcpu_nr(cpu), NULL) > 0;
151
152 if (other_cpu && is_up &&
153 HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL))
154 BUG();
155
156 if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock))
157 xen_setup_runstate_info(cpu);
158
159 rc = xen_vcpu_setup_restore(cpu);
160 if (rc)
161 pr_emerg_once("vcpu restore failed for cpu=%d err=%d. "
162 "System will hang.\n", cpu, rc);
163 /*
164 * In case xen_vcpu_setup_restore() fails, do not bring up the
165 * VCPU. This helps us avoid the resulting OOPS when the VCPU
166 * accesses pvclock_vcpu_time via xen_vcpu (which is NULL.)
167 * Note that this does not improve the situation much -- now the
168 * VM hangs instead of OOPSing -- with the VCPUs that did not
169 * fail, spinning in stop_machine(), waiting for the failed
170 * VCPUs to come up.
171 */
172 if (other_cpu && is_up && (rc == 0) &&
173 HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL))
174 BUG();
175 }
176}
177
178void xen_vcpu_info_reset(int cpu)
179{
180 if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) {
181 per_cpu(xen_vcpu, cpu) =
182 &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)];
183 } else {
184 /* Set to NULL so that if somebody accesses it we get an OOPS */
185 per_cpu(xen_vcpu, cpu) = NULL;
186 }
187}
188
189int xen_vcpu_setup(int cpu)
190{
191 struct vcpu_register_vcpu_info info;
192 int err;
193 struct vcpu_info *vcpup;
194
195 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
196
197 /*
198 * This path is called on PVHVM at bootup (xen_hvm_smp_prepare_boot_cpu)
199 * and at restore (xen_vcpu_restore). Also called for hotplugged
200 * VCPUs (cpu_init -> xen_hvm_cpu_prepare_hvm).
201 * However, the hypercall can only be done once (see below) so if a VCPU
202 * is offlined and comes back online then let's not redo the hypercall.
203 *
204 * For PV it is called during restore (xen_vcpu_restore) and bootup
205 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not
206 * use this function.
207 */
208 if (xen_hvm_domain()) {
209 if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu))
210 return 0;
211 }
212
213 if (xen_have_vcpu_info_placement) {
214 vcpup = &per_cpu(xen_vcpu_info, cpu);
215 info.mfn = arbitrary_virt_to_mfn(vcpup);
216 info.offset = offset_in_page(vcpup);
217
218 /*
219 * Check to see if the hypervisor will put the vcpu_info
220 * structure where we want it, which allows direct access via
221 * a percpu-variable.
222 * N.B. This hypercall can _only_ be called once per CPU.
223 * Subsequent calls will error out with -EINVAL. This is due to
224 * the fact that hypervisor has no unregister variant and this
225 * hypercall does not allow to over-write info.mfn and
226 * info.offset.
227 */
228 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info,
229 xen_vcpu_nr(cpu), &info);
230
231 if (err) {
232 pr_warn_once("register_vcpu_info failed: cpu=%d err=%d\n",
233 cpu, err);
234 xen_have_vcpu_info_placement = 0;
235 } else {
236 /*
237 * This cpu is using the registered vcpu info, even if
238 * later ones fail to.
239 */
240 per_cpu(xen_vcpu, cpu) = vcpup;
241 }
242 }
243
244 if (!xen_have_vcpu_info_placement)
245 xen_vcpu_info_reset(cpu);
246
247 return ((per_cpu(xen_vcpu, cpu) == NULL) ? -ENODEV : 0);
248}
249
250void xen_reboot(int reason)
251{
252 struct sched_shutdown r = { .reason = reason };
253 int cpu;
254
255 for_each_online_cpu(cpu)
256 xen_pmu_finish(cpu);
257
258 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
259 BUG();
260}
261
262void xen_emergency_restart(void)
263{
264 xen_reboot(SHUTDOWN_reboot);
265}
266
267static int
268xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr)
269{
270 if (!kexec_crash_loaded())
271 xen_reboot(SHUTDOWN_crash);
272 return NOTIFY_DONE;
273}
274
275static struct notifier_block xen_panic_block = {
276 .notifier_call = xen_panic_event,
277 .priority = INT_MIN
278};
279
280int xen_panic_handler_init(void)
281{
282 atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block);
283 return 0;
284}
285
286void xen_pin_vcpu(int cpu)
287{
288 static bool disable_pinning;
289 struct sched_pin_override pin_override;
290 int ret;
291
292 if (disable_pinning)
293 return;
294
295 pin_override.pcpu = cpu;
296 ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override);
297
298 /* Ignore errors when removing override. */
299 if (cpu < 0)
300 return;
301
302 switch (ret) {
303 case -ENOSYS:
304 pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n",
305 cpu);
306 disable_pinning = true;
307 break;
308 case -EPERM:
309 WARN(1, "Trying to pin vcpu without having privilege to do so\n");
310 disable_pinning = true;
311 break;
312 case -EINVAL:
313 case -EBUSY:
314 pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n",
315 cpu);
316 break;
317 case 0:
318 break;
319 default:
320 WARN(1, "rc %d while trying to pin vcpu\n", ret);
321 disable_pinning = true;
322 }
323}
324
325#ifdef CONFIG_HOTPLUG_CPU
326void xen_arch_register_cpu(int num)
327{
328 arch_register_cpu(num);
329}
330EXPORT_SYMBOL(xen_arch_register_cpu);
331
332void xen_arch_unregister_cpu(int num)
333{
334 arch_unregister_cpu(num);
335}
336EXPORT_SYMBOL(xen_arch_unregister_cpu);
337#endif
338
339#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
340void __init arch_xen_balloon_init(struct resource *hostmem_resource)
341{
342 struct xen_memory_map memmap;
343 int rc;
344 unsigned int i, last_guest_ram;
345 phys_addr_t max_addr = PFN_PHYS(max_pfn);
346 struct e820_table *xen_e820_table;
347 const struct e820_entry *entry;
348 struct resource *res;
349
350 if (!xen_initial_domain())
351 return;
352
353 xen_e820_table = kmalloc(sizeof(*xen_e820_table), GFP_KERNEL);
354 if (!xen_e820_table)
355 return;
356
357 memmap.nr_entries = ARRAY_SIZE(xen_e820_table->entries);
358 set_xen_guest_handle(memmap.buffer, xen_e820_table->entries);
359 rc = HYPERVISOR_memory_op(XENMEM_machine_memory_map, &memmap);
360 if (rc) {
361 pr_warn("%s: Can't read host e820 (%d)\n", __func__, rc);
362 goto out;
363 }
364
365 last_guest_ram = 0;
366 for (i = 0; i < memmap.nr_entries; i++) {
367 if (xen_e820_table->entries[i].addr >= max_addr)
368 break;
369 if (xen_e820_table->entries[i].type == E820_TYPE_RAM)
370 last_guest_ram = i;
371 }
372
373 entry = &xen_e820_table->entries[last_guest_ram];
374 if (max_addr >= entry->addr + entry->size)
375 goto out; /* No unallocated host RAM. */
376
377 hostmem_resource->start = max_addr;
378 hostmem_resource->end = entry->addr + entry->size;
379
380 /*
381 * Mark non-RAM regions between the end of dom0 RAM and end of host RAM
382 * as unavailable. The rest of that region can be used for hotplug-based
383 * ballooning.
384 */
385 for (; i < memmap.nr_entries; i++) {
386 entry = &xen_e820_table->entries[i];
387
388 if (entry->type == E820_TYPE_RAM)
389 continue;
390
391 if (entry->addr >= hostmem_resource->end)
392 break;
393
394 res = kzalloc(sizeof(*res), GFP_KERNEL);
395 if (!res)
396 goto out;
397
398 res->name = "Unavailable host RAM";
399 res->start = entry->addr;
400 res->end = (entry->addr + entry->size < hostmem_resource->end) ?
401 entry->addr + entry->size : hostmem_resource->end;
402 rc = insert_resource(hostmem_resource, res);
403 if (rc) {
404 pr_warn("%s: Can't insert [%llx - %llx) (%d)\n",
405 __func__, res->start, res->end, rc);
406 kfree(res);
407 goto out;
408 }
409 }
410
411 out:
412 kfree(xen_e820_table);
413}
414#endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */
415