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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * X86 specific Hyper-V initialization code.
4 *
5 * Copyright (C) 2016, Microsoft, Inc.
6 *
7 * Author : K. Y. Srinivasan <kys@microsoft.com>
8 */
9
10#include <linux/efi.h>
11#include <linux/types.h>
12#include <linux/bitfield.h>
13#include <linux/io.h>
14#include <asm/apic.h>
15#include <asm/desc.h>
16#include <asm/sev.h>
17#include <asm/hypervisor.h>
18#include <asm/hyperv-tlfs.h>
19#include <asm/mshyperv.h>
20#include <asm/idtentry.h>
21#include <linux/kexec.h>
22#include <linux/version.h>
23#include <linux/vmalloc.h>
24#include <linux/mm.h>
25#include <linux/hyperv.h>
26#include <linux/slab.h>
27#include <linux/kernel.h>
28#include <linux/cpuhotplug.h>
29#include <linux/syscore_ops.h>
30#include <clocksource/hyperv_timer.h>
31#include <linux/highmem.h>
32#include <linux/swiotlb.h>
33
34int hyperv_init_cpuhp;
35u64 hv_current_partition_id = ~0ull;
36EXPORT_SYMBOL_GPL(hv_current_partition_id);
37
38void *hv_hypercall_pg;
39EXPORT_SYMBOL_GPL(hv_hypercall_pg);
40
41union hv_ghcb * __percpu *hv_ghcb_pg;
42
43/* Storage to save the hypercall page temporarily for hibernation */
44static void *hv_hypercall_pg_saved;
45
46struct hv_vp_assist_page **hv_vp_assist_page;
47EXPORT_SYMBOL_GPL(hv_vp_assist_page);
48
49static int hyperv_init_ghcb(void)
50{
51 u64 ghcb_gpa;
52 void *ghcb_va;
53 void **ghcb_base;
54
55 if (!hv_isolation_type_snp())
56 return 0;
57
58 if (!hv_ghcb_pg)
59 return -EINVAL;
60
61 /*
62 * GHCB page is allocated by paravisor. The address
63 * returned by MSR_AMD64_SEV_ES_GHCB is above shared
64 * memory boundary and map it here.
65 */
66 rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
67 ghcb_va = memremap(ghcb_gpa, HV_HYP_PAGE_SIZE, MEMREMAP_WB);
68 if (!ghcb_va)
69 return -ENOMEM;
70
71 ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
72 *ghcb_base = ghcb_va;
73
74 return 0;
75}
76
77static int hv_cpu_init(unsigned int cpu)
78{
79 union hv_vp_assist_msr_contents msr = { 0 };
80 struct hv_vp_assist_page **hvp = &hv_vp_assist_page[cpu];
81 int ret;
82
83 ret = hv_common_cpu_init(cpu);
84 if (ret)
85 return ret;
86
87 if (!hv_vp_assist_page)
88 return 0;
89
90 if (hv_root_partition) {
91 /*
92 * For root partition we get the hypervisor provided VP assist
93 * page, instead of allocating a new page.
94 */
95 rdmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
96 *hvp = memremap(msr.pfn << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT,
97 PAGE_SIZE, MEMREMAP_WB);
98 } else {
99 /*
100 * The VP assist page is an "overlay" page (see Hyper-V TLFS's
101 * Section 5.2.1 "GPA Overlay Pages"). Here it must be zeroed
102 * out to make sure we always write the EOI MSR in
103 * hv_apic_eoi_write() *after* the EOI optimization is disabled
104 * in hv_cpu_die(), otherwise a CPU may not be stopped in the
105 * case of CPU offlining and the VM will hang.
106 */
107 if (!*hvp)
108 *hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO);
109 if (*hvp)
110 msr.pfn = vmalloc_to_pfn(*hvp);
111
112 }
113 if (!WARN_ON(!(*hvp))) {
114 msr.enable = 1;
115 wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
116 }
117
118 return hyperv_init_ghcb();
119}
120
121static void (*hv_reenlightenment_cb)(void);
122
123static void hv_reenlightenment_notify(struct work_struct *dummy)
124{
125 struct hv_tsc_emulation_status emu_status;
126
127 rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
128
129 /* Don't issue the callback if TSC accesses are not emulated */
130 if (hv_reenlightenment_cb && emu_status.inprogress)
131 hv_reenlightenment_cb();
132}
133static DECLARE_DELAYED_WORK(hv_reenlightenment_work, hv_reenlightenment_notify);
134
135void hyperv_stop_tsc_emulation(void)
136{
137 u64 freq;
138 struct hv_tsc_emulation_status emu_status;
139
140 rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
141 emu_status.inprogress = 0;
142 wrmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
143
144 rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
145 tsc_khz = div64_u64(freq, 1000);
146}
147EXPORT_SYMBOL_GPL(hyperv_stop_tsc_emulation);
148
149static inline bool hv_reenlightenment_available(void)
150{
151 /*
152 * Check for required features and privileges to make TSC frequency
153 * change notifications work.
154 */
155 return ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
156 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE &&
157 ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT;
158}
159
160DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_reenlightenment)
161{
162 ack_APIC_irq();
163 inc_irq_stat(irq_hv_reenlightenment_count);
164 schedule_delayed_work(&hv_reenlightenment_work, HZ/10);
165}
166
167void set_hv_tscchange_cb(void (*cb)(void))
168{
169 struct hv_reenlightenment_control re_ctrl = {
170 .vector = HYPERV_REENLIGHTENMENT_VECTOR,
171 .enabled = 1,
172 };
173 struct hv_tsc_emulation_control emu_ctrl = {.enabled = 1};
174
175 if (!hv_reenlightenment_available()) {
176 pr_warn("Hyper-V: reenlightenment support is unavailable\n");
177 return;
178 }
179
180 if (!hv_vp_index)
181 return;
182
183 hv_reenlightenment_cb = cb;
184
185 /* Make sure callback is registered before we write to MSRs */
186 wmb();
187
188 re_ctrl.target_vp = hv_vp_index[get_cpu()];
189
190 wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
191 wrmsrl(HV_X64_MSR_TSC_EMULATION_CONTROL, *((u64 *)&emu_ctrl));
192
193 put_cpu();
194}
195EXPORT_SYMBOL_GPL(set_hv_tscchange_cb);
196
197void clear_hv_tscchange_cb(void)
198{
199 struct hv_reenlightenment_control re_ctrl;
200
201 if (!hv_reenlightenment_available())
202 return;
203
204 rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
205 re_ctrl.enabled = 0;
206 wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
207
208 hv_reenlightenment_cb = NULL;
209}
210EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb);
211
212static int hv_cpu_die(unsigned int cpu)
213{
214 struct hv_reenlightenment_control re_ctrl;
215 unsigned int new_cpu;
216 void **ghcb_va;
217
218 if (hv_ghcb_pg) {
219 ghcb_va = (void **)this_cpu_ptr(hv_ghcb_pg);
220 if (*ghcb_va)
221 memunmap(*ghcb_va);
222 *ghcb_va = NULL;
223 }
224
225 hv_common_cpu_die(cpu);
226
227 if (hv_vp_assist_page && hv_vp_assist_page[cpu]) {
228 union hv_vp_assist_msr_contents msr = { 0 };
229 if (hv_root_partition) {
230 /*
231 * For root partition the VP assist page is mapped to
232 * hypervisor provided page, and thus we unmap the
233 * page here and nullify it, so that in future we have
234 * correct page address mapped in hv_cpu_init.
235 */
236 memunmap(hv_vp_assist_page[cpu]);
237 hv_vp_assist_page[cpu] = NULL;
238 rdmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
239 msr.enable = 0;
240 }
241 wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
242 }
243
244 if (hv_reenlightenment_cb == NULL)
245 return 0;
246
247 rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
248 if (re_ctrl.target_vp == hv_vp_index[cpu]) {
249 /*
250 * Reassign reenlightenment notifications to some other online
251 * CPU or just disable the feature if there are no online CPUs
252 * left (happens on hibernation).
253 */
254 new_cpu = cpumask_any_but(cpu_online_mask, cpu);
255
256 if (new_cpu < nr_cpu_ids)
257 re_ctrl.target_vp = hv_vp_index[new_cpu];
258 else
259 re_ctrl.enabled = 0;
260
261 wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
262 }
263
264 return 0;
265}
266
267static int __init hv_pci_init(void)
268{
269 int gen2vm = efi_enabled(EFI_BOOT);
270
271 /*
272 * For Generation-2 VM, we exit from pci_arch_init() by returning 0.
273 * The purpose is to suppress the harmless warning:
274 * "PCI: Fatal: No config space access function found"
275 */
276 if (gen2vm)
277 return 0;
278
279 /* For Generation-1 VM, we'll proceed in pci_arch_init(). */
280 return 1;
281}
282
283static int hv_suspend(void)
284{
285 union hv_x64_msr_hypercall_contents hypercall_msr;
286 int ret;
287
288 if (hv_root_partition)
289 return -EPERM;
290
291 /*
292 * Reset the hypercall page as it is going to be invalidated
293 * across hibernation. Setting hv_hypercall_pg to NULL ensures
294 * that any subsequent hypercall operation fails safely instead of
295 * crashing due to an access of an invalid page. The hypercall page
296 * pointer is restored on resume.
297 */
298 hv_hypercall_pg_saved = hv_hypercall_pg;
299 hv_hypercall_pg = NULL;
300
301 /* Disable the hypercall page in the hypervisor */
302 rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
303 hypercall_msr.enable = 0;
304 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
305
306 ret = hv_cpu_die(0);
307 return ret;
308}
309
310static void hv_resume(void)
311{
312 union hv_x64_msr_hypercall_contents hypercall_msr;
313 int ret;
314
315 ret = hv_cpu_init(0);
316 WARN_ON(ret);
317
318 /* Re-enable the hypercall page */
319 rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
320 hypercall_msr.enable = 1;
321 hypercall_msr.guest_physical_address =
322 vmalloc_to_pfn(hv_hypercall_pg_saved);
323 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
324
325 hv_hypercall_pg = hv_hypercall_pg_saved;
326 hv_hypercall_pg_saved = NULL;
327
328 /*
329 * Reenlightenment notifications are disabled by hv_cpu_die(0),
330 * reenable them here if hv_reenlightenment_cb was previously set.
331 */
332 if (hv_reenlightenment_cb)
333 set_hv_tscchange_cb(hv_reenlightenment_cb);
334}
335
336/* Note: when the ops are called, only CPU0 is online and IRQs are disabled. */
337static struct syscore_ops hv_syscore_ops = {
338 .suspend = hv_suspend,
339 .resume = hv_resume,
340};
341
342static void (* __initdata old_setup_percpu_clockev)(void);
343
344static void __init hv_stimer_setup_percpu_clockev(void)
345{
346 /*
347 * Ignore any errors in setting up stimer clockevents
348 * as we can run with the LAPIC timer as a fallback.
349 */
350 (void)hv_stimer_alloc(false);
351
352 /*
353 * Still register the LAPIC timer, because the direct-mode STIMER is
354 * not supported by old versions of Hyper-V. This also allows users
355 * to switch to LAPIC timer via /sys, if they want to.
356 */
357 if (old_setup_percpu_clockev)
358 old_setup_percpu_clockev();
359}
360
361static void __init hv_get_partition_id(void)
362{
363 struct hv_get_partition_id *output_page;
364 u64 status;
365 unsigned long flags;
366
367 local_irq_save(flags);
368 output_page = *this_cpu_ptr(hyperv_pcpu_output_arg);
369 status = hv_do_hypercall(HVCALL_GET_PARTITION_ID, NULL, output_page);
370 if (!hv_result_success(status)) {
371 /* No point in proceeding if this failed */
372 pr_err("Failed to get partition ID: %lld\n", status);
373 BUG();
374 }
375 hv_current_partition_id = output_page->partition_id;
376 local_irq_restore(flags);
377}
378
379/*
380 * This function is to be invoked early in the boot sequence after the
381 * hypervisor has been detected.
382 *
383 * 1. Setup the hypercall page.
384 * 2. Register Hyper-V specific clocksource.
385 * 3. Setup Hyper-V specific APIC entry points.
386 */
387void __init hyperv_init(void)
388{
389 u64 guest_id;
390 union hv_x64_msr_hypercall_contents hypercall_msr;
391 int cpuhp;
392
393 if (x86_hyper_type != X86_HYPER_MS_HYPERV)
394 return;
395
396 if (hv_common_init())
397 return;
398
399 hv_vp_assist_page = kcalloc(num_possible_cpus(),
400 sizeof(*hv_vp_assist_page), GFP_KERNEL);
401 if (!hv_vp_assist_page) {
402 ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
403 goto common_free;
404 }
405
406 if (hv_isolation_type_snp()) {
407 /* Negotiate GHCB Version. */
408 if (!hv_ghcb_negotiate_protocol())
409 hv_ghcb_terminate(SEV_TERM_SET_GEN,
410 GHCB_SEV_ES_PROT_UNSUPPORTED);
411
412 hv_ghcb_pg = alloc_percpu(union hv_ghcb *);
413 if (!hv_ghcb_pg)
414 goto free_vp_assist_page;
415 }
416
417 cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
418 hv_cpu_init, hv_cpu_die);
419 if (cpuhp < 0)
420 goto free_ghcb_page;
421
422 /*
423 * Setup the hypercall page and enable hypercalls.
424 * 1. Register the guest ID
425 * 2. Enable the hypercall and register the hypercall page
426 */
427 guest_id = hv_generate_guest_id(LINUX_VERSION_CODE);
428 wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
429
430 /* Hyper-V requires to write guest os id via ghcb in SNP IVM. */
431 hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, guest_id);
432
433 hv_hypercall_pg = __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START,
434 VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX,
435 VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
436 __builtin_return_address(0));
437 if (hv_hypercall_pg == NULL)
438 goto clean_guest_os_id;
439
440 rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
441 hypercall_msr.enable = 1;
442
443 if (hv_root_partition) {
444 struct page *pg;
445 void *src;
446
447 /*
448 * For the root partition, the hypervisor will set up its
449 * hypercall page. The hypervisor guarantees it will not show
450 * up in the root's address space. The root can't change the
451 * location of the hypercall page.
452 *
453 * Order is important here. We must enable the hypercall page
454 * so it is populated with code, then copy the code to an
455 * executable page.
456 */
457 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
458
459 pg = vmalloc_to_page(hv_hypercall_pg);
460 src = memremap(hypercall_msr.guest_physical_address << PAGE_SHIFT, PAGE_SIZE,
461 MEMREMAP_WB);
462 BUG_ON(!src);
463 memcpy_to_page(pg, 0, src, HV_HYP_PAGE_SIZE);
464 memunmap(src);
465
466 hv_remap_tsc_clocksource();
467 } else {
468 hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
469 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
470 }
471
472 /*
473 * hyperv_init() is called before LAPIC is initialized: see
474 * apic_intr_mode_init() -> x86_platform.apic_post_init() and
475 * apic_bsp_setup() -> setup_local_APIC(). The direct-mode STIMER
476 * depends on LAPIC, so hv_stimer_alloc() should be called from
477 * x86_init.timers.setup_percpu_clockev.
478 */
479 old_setup_percpu_clockev = x86_init.timers.setup_percpu_clockev;
480 x86_init.timers.setup_percpu_clockev = hv_stimer_setup_percpu_clockev;
481
482 hv_apic_init();
483
484 x86_init.pci.arch_init = hv_pci_init;
485
486 register_syscore_ops(&hv_syscore_ops);
487
488 hyperv_init_cpuhp = cpuhp;
489
490 if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_ACCESS_PARTITION_ID)
491 hv_get_partition_id();
492
493 BUG_ON(hv_root_partition && hv_current_partition_id == ~0ull);
494
495#ifdef CONFIG_PCI_MSI
496 /*
497 * If we're running as root, we want to create our own PCI MSI domain.
498 * We can't set this in hv_pci_init because that would be too late.
499 */
500 if (hv_root_partition)
501 x86_init.irqs.create_pci_msi_domain = hv_create_pci_msi_domain;
502#endif
503
504 /* Query the VMs extended capability once, so that it can be cached. */
505 hv_query_ext_cap(0);
506
507#ifdef CONFIG_SWIOTLB
508 /*
509 * Swiotlb bounce buffer needs to be mapped in extra address
510 * space. Map function doesn't work in the early place and so
511 * call swiotlb_update_mem_attributes() here.
512 */
513 if (hv_is_isolation_supported())
514 swiotlb_update_mem_attributes();
515#endif
516
517 return;
518
519clean_guest_os_id:
520 wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
521 hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, 0);
522 cpuhp_remove_state(cpuhp);
523free_ghcb_page:
524 free_percpu(hv_ghcb_pg);
525free_vp_assist_page:
526 kfree(hv_vp_assist_page);
527 hv_vp_assist_page = NULL;
528common_free:
529 hv_common_free();
530}
531
532/*
533 * This routine is called before kexec/kdump, it does the required cleanup.
534 */
535void hyperv_cleanup(void)
536{
537 union hv_x64_msr_hypercall_contents hypercall_msr;
538 union hv_reference_tsc_msr tsc_msr;
539
540 /* Reset our OS id */
541 wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
542 hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, 0);
543
544 /*
545 * Reset hypercall page reference before reset the page,
546 * let hypercall operations fail safely rather than
547 * panic the kernel for using invalid hypercall page
548 */
549 hv_hypercall_pg = NULL;
550
551 /* Reset the hypercall page */
552 hypercall_msr.as_uint64 = hv_get_register(HV_X64_MSR_HYPERCALL);
553 hypercall_msr.enable = 0;
554 hv_set_register(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
555
556 /* Reset the TSC page */
557 tsc_msr.as_uint64 = hv_get_register(HV_X64_MSR_REFERENCE_TSC);
558 tsc_msr.enable = 0;
559 hv_set_register(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
560}
561
562void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die)
563{
564 static bool panic_reported;
565 u64 guest_id;
566
567 if (in_die && !panic_on_oops)
568 return;
569
570 /*
571 * We prefer to report panic on 'die' chain as we have proper
572 * registers to report, but if we miss it (e.g. on BUG()) we need
573 * to report it on 'panic'.
574 */
575 if (panic_reported)
576 return;
577 panic_reported = true;
578
579 rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
580
581 wrmsrl(HV_X64_MSR_CRASH_P0, err);
582 wrmsrl(HV_X64_MSR_CRASH_P1, guest_id);
583 wrmsrl(HV_X64_MSR_CRASH_P2, regs->ip);
584 wrmsrl(HV_X64_MSR_CRASH_P3, regs->ax);
585 wrmsrl(HV_X64_MSR_CRASH_P4, regs->sp);
586
587 /*
588 * Let Hyper-V know there is crash data available
589 */
590 wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
591}
592EXPORT_SYMBOL_GPL(hyperv_report_panic);
593
594bool hv_is_hyperv_initialized(void)
595{
596 union hv_x64_msr_hypercall_contents hypercall_msr;
597
598 /*
599 * Ensure that we're really on Hyper-V, and not a KVM or Xen
600 * emulation of Hyper-V
601 */
602 if (x86_hyper_type != X86_HYPER_MS_HYPERV)
603 return false;
604
605 /*
606 * Verify that earlier initialization succeeded by checking
607 * that the hypercall page is setup
608 */
609 hypercall_msr.as_uint64 = 0;
610 rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
611
612 return hypercall_msr.enable;
613}
614EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);
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/types.h>
21#include <asm/apic.h>
22#include <asm/desc.h>
23#include <asm/hypervisor.h>
24#include <asm/hyperv-tlfs.h>
25#include <asm/mshyperv.h>
26#include <linux/version.h>
27#include <linux/vmalloc.h>
28#include <linux/mm.h>
29#include <linux/clockchips.h>
30#include <linux/hyperv.h>
31#include <linux/slab.h>
32#include <linux/cpuhotplug.h>
33
34#ifdef CONFIG_HYPERV_TSCPAGE
35
36static struct ms_hyperv_tsc_page *tsc_pg;
37
38struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
39{
40 return tsc_pg;
41}
42EXPORT_SYMBOL_GPL(hv_get_tsc_page);
43
44static u64 read_hv_clock_tsc(struct clocksource *arg)
45{
46 u64 current_tick = hv_read_tsc_page(tsc_pg);
47
48 if (current_tick == U64_MAX)
49 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
50
51 return current_tick;
52}
53
54static struct clocksource hyperv_cs_tsc = {
55 .name = "hyperv_clocksource_tsc_page",
56 .rating = 400,
57 .read = read_hv_clock_tsc,
58 .mask = CLOCKSOURCE_MASK(64),
59 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
60};
61#endif
62
63static u64 read_hv_clock_msr(struct clocksource *arg)
64{
65 u64 current_tick;
66 /*
67 * Read the partition counter to get the current tick count. This count
68 * is set to 0 when the partition is created and is incremented in
69 * 100 nanosecond units.
70 */
71 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
72 return current_tick;
73}
74
75static struct clocksource hyperv_cs_msr = {
76 .name = "hyperv_clocksource_msr",
77 .rating = 400,
78 .read = read_hv_clock_msr,
79 .mask = CLOCKSOURCE_MASK(64),
80 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
81};
82
83void *hv_hypercall_pg;
84EXPORT_SYMBOL_GPL(hv_hypercall_pg);
85struct clocksource *hyperv_cs;
86EXPORT_SYMBOL_GPL(hyperv_cs);
87
88u32 *hv_vp_index;
89EXPORT_SYMBOL_GPL(hv_vp_index);
90
91struct hv_vp_assist_page **hv_vp_assist_page;
92EXPORT_SYMBOL_GPL(hv_vp_assist_page);
93
94u32 hv_max_vp_index;
95
96static int hv_cpu_init(unsigned int cpu)
97{
98 u64 msr_vp_index;
99 struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
100
101 hv_get_vp_index(msr_vp_index);
102
103 hv_vp_index[smp_processor_id()] = msr_vp_index;
104
105 if (msr_vp_index > hv_max_vp_index)
106 hv_max_vp_index = msr_vp_index;
107
108 if (!hv_vp_assist_page)
109 return 0;
110
111 if (!*hvp)
112 *hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
113
114 if (*hvp) {
115 u64 val;
116
117 val = vmalloc_to_pfn(*hvp);
118 val = (val << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT) |
119 HV_X64_MSR_VP_ASSIST_PAGE_ENABLE;
120
121 wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, val);
122 }
123
124 return 0;
125}
126
127static void (*hv_reenlightenment_cb)(void);
128
129static void hv_reenlightenment_notify(struct work_struct *dummy)
130{
131 struct hv_tsc_emulation_status emu_status;
132
133 rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
134
135 /* Don't issue the callback if TSC accesses are not emulated */
136 if (hv_reenlightenment_cb && emu_status.inprogress)
137 hv_reenlightenment_cb();
138}
139static DECLARE_DELAYED_WORK(hv_reenlightenment_work, hv_reenlightenment_notify);
140
141void hyperv_stop_tsc_emulation(void)
142{
143 u64 freq;
144 struct hv_tsc_emulation_status emu_status;
145
146 rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
147 emu_status.inprogress = 0;
148 wrmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
149
150 rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
151 tsc_khz = div64_u64(freq, 1000);
152}
153EXPORT_SYMBOL_GPL(hyperv_stop_tsc_emulation);
154
155static inline bool hv_reenlightenment_available(void)
156{
157 /*
158 * Check for required features and priviliges to make TSC frequency
159 * change notifications work.
160 */
161 return ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
162 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE &&
163 ms_hyperv.features & HV_X64_ACCESS_REENLIGHTENMENT;
164}
165
166__visible void __irq_entry hyperv_reenlightenment_intr(struct pt_regs *regs)
167{
168 entering_ack_irq();
169
170 inc_irq_stat(irq_hv_reenlightenment_count);
171
172 schedule_delayed_work(&hv_reenlightenment_work, HZ/10);
173
174 exiting_irq();
175}
176
177void set_hv_tscchange_cb(void (*cb)(void))
178{
179 struct hv_reenlightenment_control re_ctrl = {
180 .vector = HYPERV_REENLIGHTENMENT_VECTOR,
181 .enabled = 1,
182 .target_vp = hv_vp_index[smp_processor_id()]
183 };
184 struct hv_tsc_emulation_control emu_ctrl = {.enabled = 1};
185
186 if (!hv_reenlightenment_available()) {
187 pr_warn("Hyper-V: reenlightenment support is unavailable\n");
188 return;
189 }
190
191 hv_reenlightenment_cb = cb;
192
193 /* Make sure callback is registered before we write to MSRs */
194 wmb();
195
196 wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
197 wrmsrl(HV_X64_MSR_TSC_EMULATION_CONTROL, *((u64 *)&emu_ctrl));
198}
199EXPORT_SYMBOL_GPL(set_hv_tscchange_cb);
200
201void clear_hv_tscchange_cb(void)
202{
203 struct hv_reenlightenment_control re_ctrl;
204
205 if (!hv_reenlightenment_available())
206 return;
207
208 rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
209 re_ctrl.enabled = 0;
210 wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
211
212 hv_reenlightenment_cb = NULL;
213}
214EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb);
215
216static int hv_cpu_die(unsigned int cpu)
217{
218 struct hv_reenlightenment_control re_ctrl;
219 unsigned int new_cpu;
220
221 if (hv_vp_assist_page && hv_vp_assist_page[cpu])
222 wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0);
223
224 if (hv_reenlightenment_cb == NULL)
225 return 0;
226
227 rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
228 if (re_ctrl.target_vp == hv_vp_index[cpu]) {
229 /* Reassign to some other online CPU */
230 new_cpu = cpumask_any_but(cpu_online_mask, cpu);
231
232 re_ctrl.target_vp = hv_vp_index[new_cpu];
233 wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
234 }
235
236 return 0;
237}
238
239/*
240 * This function is to be invoked early in the boot sequence after the
241 * hypervisor has been detected.
242 *
243 * 1. Setup the hypercall page.
244 * 2. Register Hyper-V specific clocksource.
245 */
246void hyperv_init(void)
247{
248 u64 guest_id, required_msrs;
249 union hv_x64_msr_hypercall_contents hypercall_msr;
250 int cpuhp;
251
252 if (x86_hyper_type != X86_HYPER_MS_HYPERV)
253 return;
254
255 /* Absolutely required MSRs */
256 required_msrs = HV_X64_MSR_HYPERCALL_AVAILABLE |
257 HV_X64_MSR_VP_INDEX_AVAILABLE;
258
259 if ((ms_hyperv.features & required_msrs) != required_msrs)
260 return;
261
262 /* Allocate percpu VP index */
263 hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
264 GFP_KERNEL);
265 if (!hv_vp_index)
266 return;
267
268 hv_vp_assist_page = kcalloc(num_possible_cpus(),
269 sizeof(*hv_vp_assist_page), GFP_KERNEL);
270 if (!hv_vp_assist_page) {
271 ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
272 goto free_vp_index;
273 }
274
275 cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
276 hv_cpu_init, hv_cpu_die);
277 if (cpuhp < 0)
278 goto free_vp_assist_page;
279
280 /*
281 * Setup the hypercall page and enable hypercalls.
282 * 1. Register the guest ID
283 * 2. Enable the hypercall and register the hypercall page
284 */
285 guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
286 wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
287
288 hv_hypercall_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
289 if (hv_hypercall_pg == NULL) {
290 wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
291 goto remove_cpuhp_state;
292 }
293
294 rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
295 hypercall_msr.enable = 1;
296 hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
297 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
298
299 hyper_alloc_mmu();
300
301 /*
302 * Register Hyper-V specific clocksource.
303 */
304#ifdef CONFIG_HYPERV_TSCPAGE
305 if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) {
306 union hv_x64_msr_hypercall_contents tsc_msr;
307
308 tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
309 if (!tsc_pg)
310 goto register_msr_cs;
311
312 hyperv_cs = &hyperv_cs_tsc;
313
314 rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
315
316 tsc_msr.enable = 1;
317 tsc_msr.guest_physical_address = vmalloc_to_pfn(tsc_pg);
318
319 wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
320
321 hyperv_cs_tsc.archdata.vclock_mode = VCLOCK_HVCLOCK;
322
323 clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
324 return;
325 }
326register_msr_cs:
327#endif
328 /*
329 * For 32 bit guests just use the MSR based mechanism for reading
330 * the partition counter.
331 */
332
333 hyperv_cs = &hyperv_cs_msr;
334 if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
335 clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
336
337 return;
338
339remove_cpuhp_state:
340 cpuhp_remove_state(cpuhp);
341free_vp_assist_page:
342 kfree(hv_vp_assist_page);
343 hv_vp_assist_page = NULL;
344free_vp_index:
345 kfree(hv_vp_index);
346 hv_vp_index = NULL;
347}
348
349/*
350 * This routine is called before kexec/kdump, it does the required cleanup.
351 */
352void hyperv_cleanup(void)
353{
354 union hv_x64_msr_hypercall_contents hypercall_msr;
355
356 /* Reset our OS id */
357 wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
358
359 /* Reset the hypercall page */
360 hypercall_msr.as_uint64 = 0;
361 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
362
363 /* Reset the TSC page */
364 hypercall_msr.as_uint64 = 0;
365 wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
366}
367EXPORT_SYMBOL_GPL(hyperv_cleanup);
368
369void hyperv_report_panic(struct pt_regs *regs, long err)
370{
371 static bool panic_reported;
372 u64 guest_id;
373
374 /*
375 * We prefer to report panic on 'die' chain as we have proper
376 * registers to report, but if we miss it (e.g. on BUG()) we need
377 * to report it on 'panic'.
378 */
379 if (panic_reported)
380 return;
381 panic_reported = true;
382
383 rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
384
385 wrmsrl(HV_X64_MSR_CRASH_P0, err);
386 wrmsrl(HV_X64_MSR_CRASH_P1, guest_id);
387 wrmsrl(HV_X64_MSR_CRASH_P2, regs->ip);
388 wrmsrl(HV_X64_MSR_CRASH_P3, regs->ax);
389 wrmsrl(HV_X64_MSR_CRASH_P4, regs->sp);
390
391 /*
392 * Let Hyper-V know there is crash data available
393 */
394 wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
395}
396EXPORT_SYMBOL_GPL(hyperv_report_panic);
397
398bool hv_is_hyperv_initialized(void)
399{
400 union hv_x64_msr_hypercall_contents hypercall_msr;
401
402 /*
403 * Ensure that we're really on Hyper-V, and not a KVM or Xen
404 * emulation of Hyper-V
405 */
406 if (x86_hyper_type != X86_HYPER_MS_HYPERV)
407 return false;
408
409 /*
410 * Verify that earlier initialization succeeded by checking
411 * that the hypercall page is setup
412 */
413 hypercall_msr.as_uint64 = 0;
414 rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
415
416 return hypercall_msr.enable;
417}
418EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);