Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[muen/linux.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 EXPORT_SYMBOL_GPL(hv_max_vp_index);
100
101 static int hv_cpu_init(unsigned int cpu)
102 {
103         u64 msr_vp_index;
104         struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
105         void **input_arg;
106
107         input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
108         *input_arg = page_address(alloc_page(GFP_KERNEL));
109
110         hv_get_vp_index(msr_vp_index);
111
112         hv_vp_index[smp_processor_id()] = msr_vp_index;
113
114         if (msr_vp_index > hv_max_vp_index)
115                 hv_max_vp_index = msr_vp_index;
116
117         if (!hv_vp_assist_page)
118                 return 0;
119
120         if (!*hvp)
121                 *hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
122
123         if (*hvp) {
124                 u64 val;
125
126                 val = vmalloc_to_pfn(*hvp);
127                 val = (val << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT) |
128                         HV_X64_MSR_VP_ASSIST_PAGE_ENABLE;
129
130                 wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, val);
131         }
132
133         return 0;
134 }
135
136 static void (*hv_reenlightenment_cb)(void);
137
138 static void hv_reenlightenment_notify(struct work_struct *dummy)
139 {
140         struct hv_tsc_emulation_status emu_status;
141
142         rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
143
144         /* Don't issue the callback if TSC accesses are not emulated */
145         if (hv_reenlightenment_cb && emu_status.inprogress)
146                 hv_reenlightenment_cb();
147 }
148 static DECLARE_DELAYED_WORK(hv_reenlightenment_work, hv_reenlightenment_notify);
149
150 void hyperv_stop_tsc_emulation(void)
151 {
152         u64 freq;
153         struct hv_tsc_emulation_status emu_status;
154
155         rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
156         emu_status.inprogress = 0;
157         wrmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
158
159         rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
160         tsc_khz = div64_u64(freq, 1000);
161 }
162 EXPORT_SYMBOL_GPL(hyperv_stop_tsc_emulation);
163
164 static inline bool hv_reenlightenment_available(void)
165 {
166         /*
167          * Check for required features and priviliges to make TSC frequency
168          * change notifications work.
169          */
170         return ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
171                 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE &&
172                 ms_hyperv.features & HV_X64_ACCESS_REENLIGHTENMENT;
173 }
174
175 __visible void __irq_entry hyperv_reenlightenment_intr(struct pt_regs *regs)
176 {
177         entering_ack_irq();
178
179         inc_irq_stat(irq_hv_reenlightenment_count);
180
181         schedule_delayed_work(&hv_reenlightenment_work, HZ/10);
182
183         exiting_irq();
184 }
185
186 void set_hv_tscchange_cb(void (*cb)(void))
187 {
188         struct hv_reenlightenment_control re_ctrl = {
189                 .vector = HYPERV_REENLIGHTENMENT_VECTOR,
190                 .enabled = 1,
191                 .target_vp = hv_vp_index[smp_processor_id()]
192         };
193         struct hv_tsc_emulation_control emu_ctrl = {.enabled = 1};
194
195         if (!hv_reenlightenment_available()) {
196                 pr_warn("Hyper-V: reenlightenment support is unavailable\n");
197                 return;
198         }
199
200         hv_reenlightenment_cb = cb;
201
202         /* Make sure callback is registered before we write to MSRs */
203         wmb();
204
205         wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
206         wrmsrl(HV_X64_MSR_TSC_EMULATION_CONTROL, *((u64 *)&emu_ctrl));
207 }
208 EXPORT_SYMBOL_GPL(set_hv_tscchange_cb);
209
210 void clear_hv_tscchange_cb(void)
211 {
212         struct hv_reenlightenment_control re_ctrl;
213
214         if (!hv_reenlightenment_available())
215                 return;
216
217         rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
218         re_ctrl.enabled = 0;
219         wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
220
221         hv_reenlightenment_cb = NULL;
222 }
223 EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb);
224
225 static int hv_cpu_die(unsigned int cpu)
226 {
227         struct hv_reenlightenment_control re_ctrl;
228         unsigned int new_cpu;
229         unsigned long flags;
230         void **input_arg;
231         void *input_pg = NULL;
232
233         local_irq_save(flags);
234         input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
235         input_pg = *input_arg;
236         *input_arg = NULL;
237         local_irq_restore(flags);
238         free_page((unsigned long)input_pg);
239
240         if (hv_vp_assist_page && hv_vp_assist_page[cpu])
241                 wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0);
242
243         if (hv_reenlightenment_cb == NULL)
244                 return 0;
245
246         rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
247         if (re_ctrl.target_vp == hv_vp_index[cpu]) {
248                 /* Reassign to some other online CPU */
249                 new_cpu = cpumask_any_but(cpu_online_mask, cpu);
250
251                 re_ctrl.target_vp = hv_vp_index[new_cpu];
252                 wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
253         }
254
255         return 0;
256 }
257
258 static int __init hv_pci_init(void)
259 {
260         int gen2vm = efi_enabled(EFI_BOOT);
261
262         /*
263          * For Generation-2 VM, we exit from pci_arch_init() by returning 0.
264          * The purpose is to suppress the harmless warning:
265          * "PCI: Fatal: No config space access function found"
266          */
267         if (gen2vm)
268                 return 0;
269
270         /* For Generation-1 VM, we'll proceed in pci_arch_init().  */
271         return 1;
272 }
273
274 /*
275  * This function is to be invoked early in the boot sequence after the
276  * hypervisor has been detected.
277  *
278  * 1. Setup the hypercall page.
279  * 2. Register Hyper-V specific clocksource.
280  * 3. Setup Hyper-V specific APIC entry points.
281  */
282 void __init hyperv_init(void)
283 {
284         u64 guest_id, required_msrs;
285         union hv_x64_msr_hypercall_contents hypercall_msr;
286         int cpuhp, i;
287
288         if (x86_hyper_type != X86_HYPER_MS_HYPERV)
289                 return;
290
291         /* Absolutely required MSRs */
292         required_msrs = HV_X64_MSR_HYPERCALL_AVAILABLE |
293                 HV_X64_MSR_VP_INDEX_AVAILABLE;
294
295         if ((ms_hyperv.features & required_msrs) != required_msrs)
296                 return;
297
298         /*
299          * Allocate the per-CPU state for the hypercall input arg.
300          * If this allocation fails, we will not be able to setup
301          * (per-CPU) hypercall input page and thus this failure is
302          * fatal on Hyper-V.
303          */
304         hyperv_pcpu_input_arg = alloc_percpu(void  *);
305
306         BUG_ON(hyperv_pcpu_input_arg == NULL);
307
308         /* Allocate percpu VP index */
309         hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
310                                     GFP_KERNEL);
311         if (!hv_vp_index)
312                 return;
313
314         for (i = 0; i < num_possible_cpus(); i++)
315                 hv_vp_index[i] = VP_INVAL;
316
317         hv_vp_assist_page = kcalloc(num_possible_cpus(),
318                                     sizeof(*hv_vp_assist_page), GFP_KERNEL);
319         if (!hv_vp_assist_page) {
320                 ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
321                 goto free_vp_index;
322         }
323
324         cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
325                                   hv_cpu_init, hv_cpu_die);
326         if (cpuhp < 0)
327                 goto free_vp_assist_page;
328
329         /*
330          * Setup the hypercall page and enable hypercalls.
331          * 1. Register the guest ID
332          * 2. Enable the hypercall and register the hypercall page
333          */
334         guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
335         wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
336
337         hv_hypercall_pg  = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
338         if (hv_hypercall_pg == NULL) {
339                 wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
340                 goto remove_cpuhp_state;
341         }
342
343         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
344         hypercall_msr.enable = 1;
345         hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
346         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
347
348         hv_apic_init();
349
350         x86_init.pci.arch_init = hv_pci_init;
351
352         /*
353          * Register Hyper-V specific clocksource.
354          */
355 #ifdef CONFIG_HYPERV_TSCPAGE
356         if (ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE) {
357                 union hv_x64_msr_hypercall_contents tsc_msr;
358
359                 tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
360                 if (!tsc_pg)
361                         goto register_msr_cs;
362
363                 hyperv_cs = &hyperv_cs_tsc;
364
365                 rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
366
367                 tsc_msr.enable = 1;
368                 tsc_msr.guest_physical_address = vmalloc_to_pfn(tsc_pg);
369
370                 wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
371
372                 hyperv_cs_tsc.archdata.vclock_mode = VCLOCK_HVCLOCK;
373
374                 clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
375                 return;
376         }
377 register_msr_cs:
378 #endif
379         /*
380          * For 32 bit guests just use the MSR based mechanism for reading
381          * the partition counter.
382          */
383
384         hyperv_cs = &hyperv_cs_msr;
385         if (ms_hyperv.features & HV_MSR_TIME_REF_COUNT_AVAILABLE)
386                 clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
387
388         return;
389
390 remove_cpuhp_state:
391         cpuhp_remove_state(cpuhp);
392 free_vp_assist_page:
393         kfree(hv_vp_assist_page);
394         hv_vp_assist_page = NULL;
395 free_vp_index:
396         kfree(hv_vp_index);
397         hv_vp_index = NULL;
398 }
399
400 /*
401  * This routine is called before kexec/kdump, it does the required cleanup.
402  */
403 void hyperv_cleanup(void)
404 {
405         union hv_x64_msr_hypercall_contents hypercall_msr;
406
407         /* Reset our OS id */
408         wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
409
410         /*
411          * Reset hypercall page reference before reset the page,
412          * let hypercall operations fail safely rather than
413          * panic the kernel for using invalid hypercall page
414          */
415         hv_hypercall_pg = NULL;
416
417         /* Reset the hypercall page */
418         hypercall_msr.as_uint64 = 0;
419         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
420
421         /* Reset the TSC page */
422         hypercall_msr.as_uint64 = 0;
423         wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
424 }
425 EXPORT_SYMBOL_GPL(hyperv_cleanup);
426
427 void hyperv_report_panic(struct pt_regs *regs, long err)
428 {
429         static bool panic_reported;
430         u64 guest_id;
431
432         /*
433          * We prefer to report panic on 'die' chain as we have proper
434          * registers to report, but if we miss it (e.g. on BUG()) we need
435          * to report it on 'panic'.
436          */
437         if (panic_reported)
438                 return;
439         panic_reported = true;
440
441         rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
442
443         wrmsrl(HV_X64_MSR_CRASH_P0, err);
444         wrmsrl(HV_X64_MSR_CRASH_P1, guest_id);
445         wrmsrl(HV_X64_MSR_CRASH_P2, regs->ip);
446         wrmsrl(HV_X64_MSR_CRASH_P3, regs->ax);
447         wrmsrl(HV_X64_MSR_CRASH_P4, regs->sp);
448
449         /*
450          * Let Hyper-V know there is crash data available
451          */
452         wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
453 }
454 EXPORT_SYMBOL_GPL(hyperv_report_panic);
455
456 /**
457  * hyperv_report_panic_msg - report panic message to Hyper-V
458  * @pa: physical address of the panic page containing the message
459  * @size: size of the message in the page
460  */
461 void hyperv_report_panic_msg(phys_addr_t pa, size_t size)
462 {
463         /*
464          * P3 to contain the physical address of the panic page & P4 to
465          * contain the size of the panic data in that page. Rest of the
466          * registers are no-op when the NOTIFY_MSG flag is set.
467          */
468         wrmsrl(HV_X64_MSR_CRASH_P0, 0);
469         wrmsrl(HV_X64_MSR_CRASH_P1, 0);
470         wrmsrl(HV_X64_MSR_CRASH_P2, 0);
471         wrmsrl(HV_X64_MSR_CRASH_P3, pa);
472         wrmsrl(HV_X64_MSR_CRASH_P4, size);
473
474         /*
475          * Let Hyper-V know there is crash data available along with
476          * the panic message.
477          */
478         wrmsrl(HV_X64_MSR_CRASH_CTL,
479                (HV_CRASH_CTL_CRASH_NOTIFY | HV_CRASH_CTL_CRASH_NOTIFY_MSG));
480 }
481 EXPORT_SYMBOL_GPL(hyperv_report_panic_msg);
482
483 bool hv_is_hyperv_initialized(void)
484 {
485         union hv_x64_msr_hypercall_contents hypercall_msr;
486
487         /*
488          * Ensure that we're really on Hyper-V, and not a KVM or Xen
489          * emulation of Hyper-V
490          */
491         if (x86_hyper_type != X86_HYPER_MS_HYPERV)
492                 return false;
493
494         /*
495          * Verify that earlier initialization succeeded by checking
496          * that the hypercall page is setup
497          */
498         hypercall_msr.as_uint64 = 0;
499         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
500
501         return hypercall_msr.enable;
502 }
503 EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);