7abb09e2eeb819129c6e9bcbbc1a3408e3e59c95
[sfrench/cifs-2.6.git] / arch / x86 / hyperv / hv_init.c
1 /*
2  * X86 specific Hyper-V initialization code.
3  *
4  * Copyright (C) 2016, Microsoft, Inc.
5  *
6  * Author : K. Y. Srinivasan <kys@microsoft.com>
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License version 2 as published
10  * by the Free Software Foundation.
11  *
12  * This program is distributed in the hope that it will be useful, but
13  * WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
15  * NON INFRINGEMENT.  See the GNU General Public License for more
16  * details.
17  *
18  */
19
20 #include <linux/efi.h>
21 #include <linux/types.h>
22 #include <asm/apic.h>
23 #include <asm/desc.h>
24 #include <asm/hypervisor.h>
25 #include <asm/hyperv-tlfs.h>
26 #include <asm/mshyperv.h>
27 #include <linux/version.h>
28 #include <linux/vmalloc.h>
29 #include <linux/mm.h>
30 #include <linux/clockchips.h>
31 #include <linux/hyperv.h>
32 #include <linux/slab.h>
33 #include <linux/cpuhotplug.h>
34
35 #ifdef CONFIG_HYPERV_TSCPAGE
36
37 static struct ms_hyperv_tsc_page *tsc_pg;
38
39 struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
40 {
41         return tsc_pg;
42 }
43 EXPORT_SYMBOL_GPL(hv_get_tsc_page);
44
45 static u64 read_hv_clock_tsc(struct clocksource *arg)
46 {
47         u64 current_tick = hv_read_tsc_page(tsc_pg);
48
49         if (current_tick == U64_MAX)
50                 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
51
52         return current_tick;
53 }
54
55 static struct clocksource hyperv_cs_tsc = {
56                 .name           = "hyperv_clocksource_tsc_page",
57                 .rating         = 400,
58                 .read           = read_hv_clock_tsc,
59                 .mask           = CLOCKSOURCE_MASK(64),
60                 .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
61 };
62 #endif
63
64 static u64 read_hv_clock_msr(struct clocksource *arg)
65 {
66         u64 current_tick;
67         /*
68          * Read the partition counter to get the current tick count. This count
69          * is set to 0 when the partition is created and is incremented in
70          * 100 nanosecond units.
71          */
72         rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
73         return current_tick;
74 }
75
76 static struct clocksource hyperv_cs_msr = {
77         .name           = "hyperv_clocksource_msr",
78         .rating         = 400,
79         .read           = read_hv_clock_msr,
80         .mask           = CLOCKSOURCE_MASK(64),
81         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
82 };
83
84 void *hv_hypercall_pg;
85 EXPORT_SYMBOL_GPL(hv_hypercall_pg);
86 struct clocksource *hyperv_cs;
87 EXPORT_SYMBOL_GPL(hyperv_cs);
88
89 u32 *hv_vp_index;
90 EXPORT_SYMBOL_GPL(hv_vp_index);
91
92 struct hv_vp_assist_page **hv_vp_assist_page;
93 EXPORT_SYMBOL_GPL(hv_vp_assist_page);
94
95 void  __percpu **hyperv_pcpu_input_arg;
96 EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
97
98 u32 hv_max_vp_index;
99
100 static int hv_cpu_init(unsigned int cpu)
101 {
102         u64 msr_vp_index;
103         struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
104         void **input_arg;
105
106         input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
107         *input_arg = page_address(alloc_page(GFP_KERNEL));
108
109         hv_get_vp_index(msr_vp_index);
110
111         hv_vp_index[smp_processor_id()] = msr_vp_index;
112
113         if (msr_vp_index > hv_max_vp_index)
114                 hv_max_vp_index = msr_vp_index;
115
116         if (!hv_vp_assist_page)
117                 return 0;
118
119         if (!*hvp)
120                 *hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
121
122         if (*hvp) {
123                 u64 val;
124
125                 val = vmalloc_to_pfn(*hvp);
126                 val = (val << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT) |
127                         HV_X64_MSR_VP_ASSIST_PAGE_ENABLE;
128
129                 wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, val);
130         }
131
132         return 0;
133 }
134
135 static void (*hv_reenlightenment_cb)(void);
136
137 static void hv_reenlightenment_notify(struct work_struct *dummy)
138 {
139         struct hv_tsc_emulation_status emu_status;
140
141         rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
142
143         /* Don't issue the callback if TSC accesses are not emulated */
144         if (hv_reenlightenment_cb && emu_status.inprogress)
145                 hv_reenlightenment_cb();
146 }
147 static DECLARE_DELAYED_WORK(hv_reenlightenment_work, hv_reenlightenment_notify);
148
149 void hyperv_stop_tsc_emulation(void)
150 {
151         u64 freq;
152         struct hv_tsc_emulation_status emu_status;
153
154         rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
155         emu_status.inprogress = 0;
156         wrmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
157
158         rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
159         tsc_khz = div64_u64(freq, 1000);
160 }
161 EXPORT_SYMBOL_GPL(hyperv_stop_tsc_emulation);
162
163 static inline bool hv_reenlightenment_available(void)
164 {
165         /*
166          * Check for required features and priviliges to make TSC frequency
167          * change notifications work.
168          */
169         return ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
170                 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE &&
171                 ms_hyperv.features & HV_X64_ACCESS_REENLIGHTENMENT;
172 }
173
174 __visible void __irq_entry hyperv_reenlightenment_intr(struct pt_regs *regs)
175 {
176         entering_ack_irq();
177
178         inc_irq_stat(irq_hv_reenlightenment_count);
179
180         schedule_delayed_work(&hv_reenlightenment_work, HZ/10);
181
182         exiting_irq();
183 }
184
185 void set_hv_tscchange_cb(void (*cb)(void))
186 {
187         struct hv_reenlightenment_control re_ctrl = {
188                 .vector = HYPERV_REENLIGHTENMENT_VECTOR,
189                 .enabled = 1,
190                 .target_vp = hv_vp_index[smp_processor_id()]
191         };
192         struct hv_tsc_emulation_control emu_ctrl = {.enabled = 1};
193
194         if (!hv_reenlightenment_available()) {
195                 pr_warn("Hyper-V: reenlightenment support is unavailable\n");
196                 return;
197         }
198
199         hv_reenlightenment_cb = cb;
200
201         /* Make sure callback is registered before we write to MSRs */
202         wmb();
203
204         wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
205         wrmsrl(HV_X64_MSR_TSC_EMULATION_CONTROL, *((u64 *)&emu_ctrl));
206 }
207 EXPORT_SYMBOL_GPL(set_hv_tscchange_cb);
208
209 void clear_hv_tscchange_cb(void)
210 {
211         struct hv_reenlightenment_control re_ctrl;
212
213         if (!hv_reenlightenment_available())
214                 return;
215
216         rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
217         re_ctrl.enabled = 0;
218         wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
219
220         hv_reenlightenment_cb = NULL;
221 }
222 EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb);
223
224 static int hv_cpu_die(unsigned int cpu)
225 {
226         struct hv_reenlightenment_control re_ctrl;
227         unsigned int new_cpu;
228         unsigned long flags;
229         void **input_arg;
230         void *input_pg = NULL;
231
232         local_irq_save(flags);
233         input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
234         input_pg = *input_arg;
235         *input_arg = NULL;
236         local_irq_restore(flags);
237         free_page((unsigned long)input_pg);
238
239         if (hv_vp_assist_page && hv_vp_assist_page[cpu])
240                 wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0);
241
242         if (hv_reenlightenment_cb == NULL)
243                 return 0;
244
245         rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
246         if (re_ctrl.target_vp == hv_vp_index[cpu]) {
247                 /* Reassign to some other online CPU */
248                 new_cpu = cpumask_any_but(cpu_online_mask, cpu);
249
250                 re_ctrl.target_vp = hv_vp_index[new_cpu];
251                 wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
252         }
253
254         return 0;
255 }
256
257 static int __init hv_pci_init(void)
258 {
259         int gen2vm = efi_enabled(EFI_BOOT);
260
261         /*
262          * For Generation-2 VM, we exit from pci_arch_init() by returning 0.
263          * The purpose is to suppress the harmless warning:
264          * "PCI: Fatal: No config space access function found"
265          */
266         if (gen2vm)
267                 return 0;
268
269         /* For Generation-1 VM, we'll proceed in pci_arch_init().  */
270         return 1;
271 }
272
273 /*
274  * This function is to be invoked early in the boot sequence after the
275  * hypervisor has been detected.
276  *
277  * 1. Setup the hypercall page.
278  * 2. Register Hyper-V specific clocksource.
279  * 3. Setup Hyper-V specific APIC entry points.
280  */
281 void __init hyperv_init(void)
282 {
283         u64 guest_id, required_msrs;
284         union hv_x64_msr_hypercall_contents hypercall_msr;
285         int cpuhp, i;
286
287         if (x86_hyper_type != X86_HYPER_MS_HYPERV)
288                 return;
289
290         /* Absolutely required MSRs */
291         required_msrs = HV_X64_MSR_HYPERCALL_AVAILABLE |
292                 HV_X64_MSR_VP_INDEX_AVAILABLE;
293
294         if ((ms_hyperv.features & required_msrs) != required_msrs)
295                 return;
296
297         /*
298          * Allocate the per-CPU state for the hypercall input arg.
299          * If this allocation fails, we will not be able to setup
300          * (per-CPU) hypercall input page and thus this failure is
301          * fatal on Hyper-V.
302          */
303         hyperv_pcpu_input_arg = alloc_percpu(void  *);
304
305         BUG_ON(hyperv_pcpu_input_arg == NULL);
306
307         /* Allocate percpu VP index */
308         hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
309                                     GFP_KERNEL);
310         if (!hv_vp_index)
311                 return;
312
313         for (i = 0; i < num_possible_cpus(); i++)
314                 hv_vp_index[i] = VP_INVAL;
315
316         hv_vp_assist_page = kcalloc(num_possible_cpus(),
317                                     sizeof(*hv_vp_assist_page), GFP_KERNEL);
318         if (!hv_vp_assist_page) {
319                 ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
320                 goto free_vp_index;
321         }
322
323         cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
324                                   hv_cpu_init, hv_cpu_die);
325         if (cpuhp < 0)
326                 goto free_vp_assist_page;
327
328         /*
329          * Setup the hypercall page and enable hypercalls.
330          * 1. Register the guest ID
331          * 2. Enable the hypercall and register the hypercall page
332          */
333         guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
334         wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
335
336         hv_hypercall_pg  = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
337         if (hv_hypercall_pg == NULL) {
338                 wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
339                 goto remove_cpuhp_state;
340         }
341
342         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
343         hypercall_msr.enable = 1;
344         hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
345         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
346
347         hv_apic_init();
348
349         x86_init.pci.arch_init = hv_pci_init;
350
351         /*
352          * Register Hyper-V specific clocksource.
353          */
354 #ifdef CONFIG_HYPERV_TSCPAGE
355         if (ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE) {
356                 union hv_x64_msr_hypercall_contents tsc_msr;
357
358                 tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
359                 if (!tsc_pg)
360                         goto register_msr_cs;
361
362                 hyperv_cs = &hyperv_cs_tsc;
363
364                 rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
365
366                 tsc_msr.enable = 1;
367                 tsc_msr.guest_physical_address = vmalloc_to_pfn(tsc_pg);
368
369                 wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
370
371                 hyperv_cs_tsc.archdata.vclock_mode = VCLOCK_HVCLOCK;
372
373                 clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
374                 return;
375         }
376 register_msr_cs:
377 #endif
378         /*
379          * For 32 bit guests just use the MSR based mechanism for reading
380          * the partition counter.
381          */
382
383         hyperv_cs = &hyperv_cs_msr;
384         if (ms_hyperv.features & HV_MSR_TIME_REF_COUNT_AVAILABLE)
385                 clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
386
387         return;
388
389 remove_cpuhp_state:
390         cpuhp_remove_state(cpuhp);
391 free_vp_assist_page:
392         kfree(hv_vp_assist_page);
393         hv_vp_assist_page = NULL;
394 free_vp_index:
395         kfree(hv_vp_index);
396         hv_vp_index = NULL;
397 }
398
399 /*
400  * This routine is called before kexec/kdump, it does the required cleanup.
401  */
402 void hyperv_cleanup(void)
403 {
404         union hv_x64_msr_hypercall_contents hypercall_msr;
405
406         /* Reset our OS id */
407         wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
408
409         /* Reset the hypercall page */
410         hypercall_msr.as_uint64 = 0;
411         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
412
413         /* Reset the TSC page */
414         hypercall_msr.as_uint64 = 0;
415         wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
416 }
417 EXPORT_SYMBOL_GPL(hyperv_cleanup);
418
419 void hyperv_report_panic(struct pt_regs *regs, long err)
420 {
421         static bool panic_reported;
422         u64 guest_id;
423
424         /*
425          * We prefer to report panic on 'die' chain as we have proper
426          * registers to report, but if we miss it (e.g. on BUG()) we need
427          * to report it on 'panic'.
428          */
429         if (panic_reported)
430                 return;
431         panic_reported = true;
432
433         rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
434
435         wrmsrl(HV_X64_MSR_CRASH_P0, err);
436         wrmsrl(HV_X64_MSR_CRASH_P1, guest_id);
437         wrmsrl(HV_X64_MSR_CRASH_P2, regs->ip);
438         wrmsrl(HV_X64_MSR_CRASH_P3, regs->ax);
439         wrmsrl(HV_X64_MSR_CRASH_P4, regs->sp);
440
441         /*
442          * Let Hyper-V know there is crash data available
443          */
444         wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
445 }
446 EXPORT_SYMBOL_GPL(hyperv_report_panic);
447
448 /**
449  * hyperv_report_panic_msg - report panic message to Hyper-V
450  * @pa: physical address of the panic page containing the message
451  * @size: size of the message in the page
452  */
453 void hyperv_report_panic_msg(phys_addr_t pa, size_t size)
454 {
455         /*
456          * P3 to contain the physical address of the panic page & P4 to
457          * contain the size of the panic data in that page. Rest of the
458          * registers are no-op when the NOTIFY_MSG flag is set.
459          */
460         wrmsrl(HV_X64_MSR_CRASH_P0, 0);
461         wrmsrl(HV_X64_MSR_CRASH_P1, 0);
462         wrmsrl(HV_X64_MSR_CRASH_P2, 0);
463         wrmsrl(HV_X64_MSR_CRASH_P3, pa);
464         wrmsrl(HV_X64_MSR_CRASH_P4, size);
465
466         /*
467          * Let Hyper-V know there is crash data available along with
468          * the panic message.
469          */
470         wrmsrl(HV_X64_MSR_CRASH_CTL,
471                (HV_CRASH_CTL_CRASH_NOTIFY | HV_CRASH_CTL_CRASH_NOTIFY_MSG));
472 }
473 EXPORT_SYMBOL_GPL(hyperv_report_panic_msg);
474
475 bool hv_is_hyperv_initialized(void)
476 {
477         union hv_x64_msr_hypercall_contents hypercall_msr;
478
479         /*
480          * Ensure that we're really on Hyper-V, and not a KVM or Xen
481          * emulation of Hyper-V
482          */
483         if (x86_hyper_type != X86_HYPER_MS_HYPERV)
484                 return false;
485
486         /*
487          * Verify that earlier initialization succeeded by checking
488          * that the hypercall page is setup
489          */
490         hypercall_msr.as_uint64 = 0;
491         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
492
493         return hypercall_msr.enable;
494 }
495 EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);