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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// 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#define pr_fmt(fmt) "Hyper-V: " fmt
11
12#include <linux/efi.h>
13#include <linux/types.h>
14#include <linux/bitfield.h>
15#include <linux/io.h>
16#include <asm/apic.h>
17#include <asm/desc.h>
18#include <asm/e820/api.h>
19#include <asm/sev.h>
20#include <asm/ibt.h>
21#include <asm/hypervisor.h>
22#include <asm/hyperv-tlfs.h>
23#include <asm/mshyperv.h>
24#include <asm/idtentry.h>
25#include <asm/set_memory.h>
26#include <linux/kexec.h>
27#include <linux/version.h>
28#include <linux/vmalloc.h>
29#include <linux/mm.h>
30#include <linux/hyperv.h>
31#include <linux/slab.h>
32#include <linux/kernel.h>
33#include <linux/cpuhotplug.h>
34#include <linux/syscore_ops.h>
35#include <clocksource/hyperv_timer.h>
36#include <linux/highmem.h>
37
38int hyperv_init_cpuhp;
39u64 hv_current_partition_id = ~0ull;
40EXPORT_SYMBOL_GPL(hv_current_partition_id);
41
42void *hv_hypercall_pg;
43EXPORT_SYMBOL_GPL(hv_hypercall_pg);
44
45union hv_ghcb * __percpu *hv_ghcb_pg;
46
47/* Storage to save the hypercall page temporarily for hibernation */
48static void *hv_hypercall_pg_saved;
49
50struct hv_vp_assist_page **hv_vp_assist_page;
51EXPORT_SYMBOL_GPL(hv_vp_assist_page);
52
53static int hyperv_init_ghcb(void)
54{
55 u64 ghcb_gpa;
56 void *ghcb_va;
57 void **ghcb_base;
58
59 if (!ms_hyperv.paravisor_present || !hv_isolation_type_snp())
60 return 0;
61
62 if (!hv_ghcb_pg)
63 return -EINVAL;
64
65 /*
66 * GHCB page is allocated by paravisor. The address
67 * returned by MSR_AMD64_SEV_ES_GHCB is above shared
68 * memory boundary and map it here.
69 */
70 rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
71
72 /* Mask out vTOM bit. ioremap_cache() maps decrypted */
73 ghcb_gpa &= ~ms_hyperv.shared_gpa_boundary;
74 ghcb_va = (void *)ioremap_cache(ghcb_gpa, HV_HYP_PAGE_SIZE);
75 if (!ghcb_va)
76 return -ENOMEM;
77
78 ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
79 *ghcb_base = ghcb_va;
80
81 return 0;
82}
83
84static int hv_cpu_init(unsigned int cpu)
85{
86 union hv_vp_assist_msr_contents msr = { 0 };
87 struct hv_vp_assist_page **hvp;
88 int ret;
89
90 ret = hv_common_cpu_init(cpu);
91 if (ret)
92 return ret;
93
94 if (!hv_vp_assist_page)
95 return 0;
96
97 hvp = &hv_vp_assist_page[cpu];
98 if (hv_root_partition) {
99 /*
100 * For root partition we get the hypervisor provided VP assist
101 * page, instead of allocating a new page.
102 */
103 rdmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
104 *hvp = memremap(msr.pfn << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT,
105 PAGE_SIZE, MEMREMAP_WB);
106 } else {
107 /*
108 * The VP assist page is an "overlay" page (see Hyper-V TLFS's
109 * Section 5.2.1 "GPA Overlay Pages"). Here it must be zeroed
110 * out to make sure we always write the EOI MSR in
111 * hv_apic_eoi_write() *after* the EOI optimization is disabled
112 * in hv_cpu_die(), otherwise a CPU may not be stopped in the
113 * case of CPU offlining and the VM will hang.
114 */
115 if (!*hvp) {
116 *hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO);
117
118 /*
119 * Hyper-V should never specify a VM that is a Confidential
120 * VM and also running in the root partition. Root partition
121 * is blocked to run in Confidential VM. So only decrypt assist
122 * page in non-root partition here.
123 */
124 if (*hvp && !ms_hyperv.paravisor_present && hv_isolation_type_snp()) {
125 WARN_ON_ONCE(set_memory_decrypted((unsigned long)(*hvp), 1));
126 memset(*hvp, 0, PAGE_SIZE);
127 }
128 }
129
130 if (*hvp)
131 msr.pfn = vmalloc_to_pfn(*hvp);
132
133 }
134 if (!WARN_ON(!(*hvp))) {
135 msr.enable = 1;
136 wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
137 }
138
139 return hyperv_init_ghcb();
140}
141
142static void (*hv_reenlightenment_cb)(void);
143
144static void hv_reenlightenment_notify(struct work_struct *dummy)
145{
146 struct hv_tsc_emulation_status emu_status;
147
148 rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
149
150 /* Don't issue the callback if TSC accesses are not emulated */
151 if (hv_reenlightenment_cb && emu_status.inprogress)
152 hv_reenlightenment_cb();
153}
154static DECLARE_DELAYED_WORK(hv_reenlightenment_work, hv_reenlightenment_notify);
155
156void hyperv_stop_tsc_emulation(void)
157{
158 u64 freq;
159 struct hv_tsc_emulation_status emu_status;
160
161 rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
162 emu_status.inprogress = 0;
163 wrmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
164
165 rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
166 tsc_khz = div64_u64(freq, 1000);
167}
168EXPORT_SYMBOL_GPL(hyperv_stop_tsc_emulation);
169
170static inline bool hv_reenlightenment_available(void)
171{
172 /*
173 * Check for required features and privileges to make TSC frequency
174 * change notifications work.
175 */
176 return ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
177 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE &&
178 ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT;
179}
180
181DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_reenlightenment)
182{
183 apic_eoi();
184 inc_irq_stat(irq_hv_reenlightenment_count);
185 schedule_delayed_work(&hv_reenlightenment_work, HZ/10);
186}
187
188void set_hv_tscchange_cb(void (*cb)(void))
189{
190 struct hv_reenlightenment_control re_ctrl = {
191 .vector = HYPERV_REENLIGHTENMENT_VECTOR,
192 .enabled = 1,
193 };
194 struct hv_tsc_emulation_control emu_ctrl = {.enabled = 1};
195
196 if (!hv_reenlightenment_available()) {
197 pr_warn("reenlightenment support is unavailable\n");
198 return;
199 }
200
201 if (!hv_vp_index)
202 return;
203
204 hv_reenlightenment_cb = cb;
205
206 /* Make sure callback is registered before we write to MSRs */
207 wmb();
208
209 re_ctrl.target_vp = hv_vp_index[get_cpu()];
210
211 wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
212 wrmsrl(HV_X64_MSR_TSC_EMULATION_CONTROL, *((u64 *)&emu_ctrl));
213
214 put_cpu();
215}
216EXPORT_SYMBOL_GPL(set_hv_tscchange_cb);
217
218void clear_hv_tscchange_cb(void)
219{
220 struct hv_reenlightenment_control re_ctrl;
221
222 if (!hv_reenlightenment_available())
223 return;
224
225 rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
226 re_ctrl.enabled = 0;
227 wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
228
229 hv_reenlightenment_cb = NULL;
230}
231EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb);
232
233static int hv_cpu_die(unsigned int cpu)
234{
235 struct hv_reenlightenment_control re_ctrl;
236 unsigned int new_cpu;
237 void **ghcb_va;
238
239 if (hv_ghcb_pg) {
240 ghcb_va = (void **)this_cpu_ptr(hv_ghcb_pg);
241 if (*ghcb_va)
242 iounmap(*ghcb_va);
243 *ghcb_va = NULL;
244 }
245
246 hv_common_cpu_die(cpu);
247
248 if (hv_vp_assist_page && hv_vp_assist_page[cpu]) {
249 union hv_vp_assist_msr_contents msr = { 0 };
250 if (hv_root_partition) {
251 /*
252 * For root partition the VP assist page is mapped to
253 * hypervisor provided page, and thus we unmap the
254 * page here and nullify it, so that in future we have
255 * correct page address mapped in hv_cpu_init.
256 */
257 memunmap(hv_vp_assist_page[cpu]);
258 hv_vp_assist_page[cpu] = NULL;
259 rdmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
260 msr.enable = 0;
261 }
262 wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
263 }
264
265 if (hv_reenlightenment_cb == NULL)
266 return 0;
267
268 rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
269 if (re_ctrl.target_vp == hv_vp_index[cpu]) {
270 /*
271 * Reassign reenlightenment notifications to some other online
272 * CPU or just disable the feature if there are no online CPUs
273 * left (happens on hibernation).
274 */
275 new_cpu = cpumask_any_but(cpu_online_mask, cpu);
276
277 if (new_cpu < nr_cpu_ids)
278 re_ctrl.target_vp = hv_vp_index[new_cpu];
279 else
280 re_ctrl.enabled = 0;
281
282 wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
283 }
284
285 return 0;
286}
287
288static int __init hv_pci_init(void)
289{
290 bool gen2vm = efi_enabled(EFI_BOOT);
291
292 /*
293 * A Generation-2 VM doesn't support legacy PCI/PCIe, so both
294 * raw_pci_ops and raw_pci_ext_ops are NULL, and pci_subsys_init() ->
295 * pcibios_init() doesn't call pcibios_resource_survey() ->
296 * e820__reserve_resources_late(); as a result, any emulated persistent
297 * memory of E820_TYPE_PRAM (12) via the kernel parameter
298 * memmap=nn[KMG]!ss is not added into iomem_resource and hence can't be
299 * detected by register_e820_pmem(). Fix this by directly calling
300 * e820__reserve_resources_late() here: e820__reserve_resources_late()
301 * depends on e820__reserve_resources(), which has been called earlier
302 * from setup_arch(). Note: e820__reserve_resources_late() also adds
303 * any memory of E820_TYPE_PMEM (7) into iomem_resource, and
304 * acpi_nfit_register_region() -> acpi_nfit_insert_resource() ->
305 * region_intersects() returns REGION_INTERSECTS, so the memory of
306 * E820_TYPE_PMEM won't get added twice.
307 *
308 * We return 0 here so that pci_arch_init() won't print the warning:
309 * "PCI: Fatal: No config space access function found"
310 */
311 if (gen2vm) {
312 e820__reserve_resources_late();
313 return 0;
314 }
315
316 /* For Generation-1 VM, we'll proceed in pci_arch_init(). */
317 return 1;
318}
319
320static int hv_suspend(void)
321{
322 union hv_x64_msr_hypercall_contents hypercall_msr;
323 int ret;
324
325 if (hv_root_partition)
326 return -EPERM;
327
328 /*
329 * Reset the hypercall page as it is going to be invalidated
330 * across hibernation. Setting hv_hypercall_pg to NULL ensures
331 * that any subsequent hypercall operation fails safely instead of
332 * crashing due to an access of an invalid page. The hypercall page
333 * pointer is restored on resume.
334 */
335 hv_hypercall_pg_saved = hv_hypercall_pg;
336 hv_hypercall_pg = NULL;
337
338 /* Disable the hypercall page in the hypervisor */
339 rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
340 hypercall_msr.enable = 0;
341 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
342
343 ret = hv_cpu_die(0);
344 return ret;
345}
346
347static void hv_resume(void)
348{
349 union hv_x64_msr_hypercall_contents hypercall_msr;
350 int ret;
351
352 ret = hv_cpu_init(0);
353 WARN_ON(ret);
354
355 /* Re-enable the hypercall page */
356 rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
357 hypercall_msr.enable = 1;
358 hypercall_msr.guest_physical_address =
359 vmalloc_to_pfn(hv_hypercall_pg_saved);
360 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
361
362 hv_hypercall_pg = hv_hypercall_pg_saved;
363 hv_hypercall_pg_saved = NULL;
364
365 /*
366 * Reenlightenment notifications are disabled by hv_cpu_die(0),
367 * reenable them here if hv_reenlightenment_cb was previously set.
368 */
369 if (hv_reenlightenment_cb)
370 set_hv_tscchange_cb(hv_reenlightenment_cb);
371}
372
373/* Note: when the ops are called, only CPU0 is online and IRQs are disabled. */
374static struct syscore_ops hv_syscore_ops = {
375 .suspend = hv_suspend,
376 .resume = hv_resume,
377};
378
379static void (* __initdata old_setup_percpu_clockev)(void);
380
381static void __init hv_stimer_setup_percpu_clockev(void)
382{
383 /*
384 * Ignore any errors in setting up stimer clockevents
385 * as we can run with the LAPIC timer as a fallback.
386 */
387 (void)hv_stimer_alloc(false);
388
389 /*
390 * Still register the LAPIC timer, because the direct-mode STIMER is
391 * not supported by old versions of Hyper-V. This also allows users
392 * to switch to LAPIC timer via /sys, if they want to.
393 */
394 if (old_setup_percpu_clockev)
395 old_setup_percpu_clockev();
396}
397
398static void __init hv_get_partition_id(void)
399{
400 struct hv_get_partition_id *output_page;
401 u64 status;
402 unsigned long flags;
403
404 local_irq_save(flags);
405 output_page = *this_cpu_ptr(hyperv_pcpu_output_arg);
406 status = hv_do_hypercall(HVCALL_GET_PARTITION_ID, NULL, output_page);
407 if (!hv_result_success(status)) {
408 /* No point in proceeding if this failed */
409 pr_err("Failed to get partition ID: %lld\n", status);
410 BUG();
411 }
412 hv_current_partition_id = output_page->partition_id;
413 local_irq_restore(flags);
414}
415
416#if IS_ENABLED(CONFIG_HYPERV_VTL_MODE)
417static u8 __init get_vtl(void)
418{
419 u64 control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_REGISTERS;
420 struct hv_get_vp_registers_input *input;
421 struct hv_get_vp_registers_output *output;
422 unsigned long flags;
423 u64 ret;
424
425 local_irq_save(flags);
426 input = *this_cpu_ptr(hyperv_pcpu_input_arg);
427 output = (struct hv_get_vp_registers_output *)input;
428
429 memset(input, 0, struct_size(input, element, 1));
430 input->header.partitionid = HV_PARTITION_ID_SELF;
431 input->header.vpindex = HV_VP_INDEX_SELF;
432 input->header.inputvtl = 0;
433 input->element[0].name0 = HV_X64_REGISTER_VSM_VP_STATUS;
434
435 ret = hv_do_hypercall(control, input, output);
436 if (hv_result_success(ret)) {
437 ret = output->as64.low & HV_X64_VTL_MASK;
438 } else {
439 pr_err("Failed to get VTL(error: %lld) exiting...\n", ret);
440 BUG();
441 }
442
443 local_irq_restore(flags);
444 return ret;
445}
446#else
447static inline u8 get_vtl(void) { return 0; }
448#endif
449
450/*
451 * This function is to be invoked early in the boot sequence after the
452 * hypervisor has been detected.
453 *
454 * 1. Setup the hypercall page.
455 * 2. Register Hyper-V specific clocksource.
456 * 3. Setup Hyper-V specific APIC entry points.
457 */
458void __init hyperv_init(void)
459{
460 u64 guest_id;
461 union hv_x64_msr_hypercall_contents hypercall_msr;
462 int cpuhp;
463
464 if (x86_hyper_type != X86_HYPER_MS_HYPERV)
465 return;
466
467 if (hv_common_init())
468 return;
469
470 /*
471 * The VP assist page is useless to a TDX guest: the only use we
472 * would have for it is lazy EOI, which can not be used with TDX.
473 */
474 if (hv_isolation_type_tdx())
475 hv_vp_assist_page = NULL;
476 else
477 hv_vp_assist_page = kcalloc(num_possible_cpus(),
478 sizeof(*hv_vp_assist_page),
479 GFP_KERNEL);
480 if (!hv_vp_assist_page) {
481 ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
482
483 if (!hv_isolation_type_tdx())
484 goto common_free;
485 }
486
487 if (ms_hyperv.paravisor_present && hv_isolation_type_snp()) {
488 /* Negotiate GHCB Version. */
489 if (!hv_ghcb_negotiate_protocol())
490 hv_ghcb_terminate(SEV_TERM_SET_GEN,
491 GHCB_SEV_ES_PROT_UNSUPPORTED);
492
493 hv_ghcb_pg = alloc_percpu(union hv_ghcb *);
494 if (!hv_ghcb_pg)
495 goto free_vp_assist_page;
496 }
497
498 cpuhp = cpuhp_setup_state(CPUHP_AP_HYPERV_ONLINE, "x86/hyperv_init:online",
499 hv_cpu_init, hv_cpu_die);
500 if (cpuhp < 0)
501 goto free_ghcb_page;
502
503 /*
504 * Setup the hypercall page and enable hypercalls.
505 * 1. Register the guest ID
506 * 2. Enable the hypercall and register the hypercall page
507 *
508 * A TDX VM with no paravisor only uses TDX GHCI rather than hv_hypercall_pg:
509 * when the hypercall input is a page, such a VM must pass a decrypted
510 * page to Hyper-V, e.g. hv_post_message() uses the per-CPU page
511 * hyperv_pcpu_input_arg, which is decrypted if no paravisor is present.
512 *
513 * A TDX VM with the paravisor uses hv_hypercall_pg for most hypercalls,
514 * which are handled by the paravisor and the VM must use an encrypted
515 * input page: in such a VM, the hyperv_pcpu_input_arg is encrypted and
516 * used in the hypercalls, e.g. see hv_mark_gpa_visibility() and
517 * hv_arch_irq_unmask(). Such a VM uses TDX GHCI for two hypercalls:
518 * 1. HVCALL_SIGNAL_EVENT: see vmbus_set_event() and _hv_do_fast_hypercall8().
519 * 2. HVCALL_POST_MESSAGE: the input page must be a decrypted page, i.e.
520 * hv_post_message() in such a VM can't use the encrypted hyperv_pcpu_input_arg;
521 * instead, hv_post_message() uses the post_msg_page, which is decrypted
522 * in such a VM and is only used in such a VM.
523 */
524 guest_id = hv_generate_guest_id(LINUX_VERSION_CODE);
525 wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
526
527 /* With the paravisor, the VM must also write the ID via GHCB/GHCI */
528 hv_ivm_msr_write(HV_X64_MSR_GUEST_OS_ID, guest_id);
529
530 /* A TDX VM with no paravisor only uses TDX GHCI rather than hv_hypercall_pg */
531 if (hv_isolation_type_tdx() && !ms_hyperv.paravisor_present)
532 goto skip_hypercall_pg_init;
533
534 hv_hypercall_pg = __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START,
535 VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX,
536 VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
537 __builtin_return_address(0));
538 if (hv_hypercall_pg == NULL)
539 goto clean_guest_os_id;
540
541 rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
542 hypercall_msr.enable = 1;
543
544 if (hv_root_partition) {
545 struct page *pg;
546 void *src;
547
548 /*
549 * For the root partition, the hypervisor will set up its
550 * hypercall page. The hypervisor guarantees it will not show
551 * up in the root's address space. The root can't change the
552 * location of the hypercall page.
553 *
554 * Order is important here. We must enable the hypercall page
555 * so it is populated with code, then copy the code to an
556 * executable page.
557 */
558 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
559
560 pg = vmalloc_to_page(hv_hypercall_pg);
561 src = memremap(hypercall_msr.guest_physical_address << PAGE_SHIFT, PAGE_SIZE,
562 MEMREMAP_WB);
563 BUG_ON(!src);
564 memcpy_to_page(pg, 0, src, HV_HYP_PAGE_SIZE);
565 memunmap(src);
566
567 hv_remap_tsc_clocksource();
568 } else {
569 hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
570 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
571 }
572
573skip_hypercall_pg_init:
574 /*
575 * Some versions of Hyper-V that provide IBT in guest VMs have a bug
576 * in that there's no ENDBR64 instruction at the entry to the
577 * hypercall page. Because hypercalls are invoked via an indirect call
578 * to the hypercall page, all hypercall attempts fail when IBT is
579 * enabled, and Linux panics. For such buggy versions, disable IBT.
580 *
581 * Fixed versions of Hyper-V always provide ENDBR64 on the hypercall
582 * page, so if future Linux kernel versions enable IBT for 32-bit
583 * builds, additional hypercall page hackery will be required here
584 * to provide an ENDBR32.
585 */
586#ifdef CONFIG_X86_KERNEL_IBT
587 if (cpu_feature_enabled(X86_FEATURE_IBT) &&
588 *(u32 *)hv_hypercall_pg != gen_endbr()) {
589 setup_clear_cpu_cap(X86_FEATURE_IBT);
590 pr_warn("Disabling IBT because of Hyper-V bug\n");
591 }
592#endif
593
594 /*
595 * hyperv_init() is called before LAPIC is initialized: see
596 * apic_intr_mode_init() -> x86_platform.apic_post_init() and
597 * apic_bsp_setup() -> setup_local_APIC(). The direct-mode STIMER
598 * depends on LAPIC, so hv_stimer_alloc() should be called from
599 * x86_init.timers.setup_percpu_clockev.
600 */
601 old_setup_percpu_clockev = x86_init.timers.setup_percpu_clockev;
602 x86_init.timers.setup_percpu_clockev = hv_stimer_setup_percpu_clockev;
603
604 hv_apic_init();
605
606 x86_init.pci.arch_init = hv_pci_init;
607
608 register_syscore_ops(&hv_syscore_ops);
609
610 hyperv_init_cpuhp = cpuhp;
611
612 if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_ACCESS_PARTITION_ID)
613 hv_get_partition_id();
614
615 BUG_ON(hv_root_partition && hv_current_partition_id == ~0ull);
616
617#ifdef CONFIG_PCI_MSI
618 /*
619 * If we're running as root, we want to create our own PCI MSI domain.
620 * We can't set this in hv_pci_init because that would be too late.
621 */
622 if (hv_root_partition)
623 x86_init.irqs.create_pci_msi_domain = hv_create_pci_msi_domain;
624#endif
625
626 /* Query the VMs extended capability once, so that it can be cached. */
627 hv_query_ext_cap(0);
628
629 /* Find the VTL */
630 ms_hyperv.vtl = get_vtl();
631
632 if (ms_hyperv.vtl > 0) /* non default VTL */
633 hv_vtl_early_init();
634
635 return;
636
637clean_guest_os_id:
638 wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
639 hv_ivm_msr_write(HV_X64_MSR_GUEST_OS_ID, 0);
640 cpuhp_remove_state(cpuhp);
641free_ghcb_page:
642 free_percpu(hv_ghcb_pg);
643free_vp_assist_page:
644 kfree(hv_vp_assist_page);
645 hv_vp_assist_page = NULL;
646common_free:
647 hv_common_free();
648}
649
650/*
651 * This routine is called before kexec/kdump, it does the required cleanup.
652 */
653void hyperv_cleanup(void)
654{
655 union hv_x64_msr_hypercall_contents hypercall_msr;
656 union hv_reference_tsc_msr tsc_msr;
657
658 /* Reset our OS id */
659 wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
660 hv_ivm_msr_write(HV_X64_MSR_GUEST_OS_ID, 0);
661
662 /*
663 * Reset hypercall page reference before reset the page,
664 * let hypercall operations fail safely rather than
665 * panic the kernel for using invalid hypercall page
666 */
667 hv_hypercall_pg = NULL;
668
669 /* Reset the hypercall page */
670 hypercall_msr.as_uint64 = hv_get_register(HV_X64_MSR_HYPERCALL);
671 hypercall_msr.enable = 0;
672 hv_set_register(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
673
674 /* Reset the TSC page */
675 tsc_msr.as_uint64 = hv_get_register(HV_X64_MSR_REFERENCE_TSC);
676 tsc_msr.enable = 0;
677 hv_set_register(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
678}
679
680void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die)
681{
682 static bool panic_reported;
683 u64 guest_id;
684
685 if (in_die && !panic_on_oops)
686 return;
687
688 /*
689 * We prefer to report panic on 'die' chain as we have proper
690 * registers to report, but if we miss it (e.g. on BUG()) we need
691 * to report it on 'panic'.
692 */
693 if (panic_reported)
694 return;
695 panic_reported = true;
696
697 rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
698
699 wrmsrl(HV_X64_MSR_CRASH_P0, err);
700 wrmsrl(HV_X64_MSR_CRASH_P1, guest_id);
701 wrmsrl(HV_X64_MSR_CRASH_P2, regs->ip);
702 wrmsrl(HV_X64_MSR_CRASH_P3, regs->ax);
703 wrmsrl(HV_X64_MSR_CRASH_P4, regs->sp);
704
705 /*
706 * Let Hyper-V know there is crash data available
707 */
708 wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
709}
710EXPORT_SYMBOL_GPL(hyperv_report_panic);
711
712bool hv_is_hyperv_initialized(void)
713{
714 union hv_x64_msr_hypercall_contents hypercall_msr;
715
716 /*
717 * Ensure that we're really on Hyper-V, and not a KVM or Xen
718 * emulation of Hyper-V
719 */
720 if (x86_hyper_type != X86_HYPER_MS_HYPERV)
721 return false;
722
723 /* A TDX VM with no paravisor uses TDX GHCI call rather than hv_hypercall_pg */
724 if (hv_isolation_type_tdx() && !ms_hyperv.paravisor_present)
725 return true;
726 /*
727 * Verify that earlier initialization succeeded by checking
728 * that the hypercall page is setup
729 */
730 hypercall_msr.as_uint64 = 0;
731 rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
732
733 return hypercall_msr.enable;
734}
735EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);