hv_init.c

  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/hypervisor.h>
 21#include <hyperv/hvhdk.h>
 22#include <asm/mshyperv.h>
 23#include <asm/msr.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/slab.h>
 31#include <linux/kernel.h>
 32#include <linux/cpuhotplug.h>
 33#include <linux/syscore_ops.h>
 34#include <clocksource/hyperv_timer.h>
 35#include <linux/highmem.h>
 36#include <linux/export.h>
 37
 38void *hv_hypercall_pg;
 39
 40#ifdef CONFIG_X86_64
 41static u64 __hv_hyperfail(u64 control, u64 param1, u64 param2)
 42{
 43	return U64_MAX;
 44}
 45
 46DEFINE_STATIC_CALL(__hv_hypercall, __hv_hyperfail);
 47
 48u64 hv_std_hypercall(u64 control, u64 param1, u64 param2)
 49{
 50	u64 hv_status;
 51
 52	register u64 __r8 asm("r8") = param2;
 53	asm volatile ("call " STATIC_CALL_TRAMP_STR(__hv_hypercall)
 54		      : "=a" (hv_status), ASM_CALL_CONSTRAINT,
 55		        "+c" (control), "+d" (param1), "+r" (__r8)
 56		      : : "cc", "memory", "r9", "r10", "r11");
 57
 58	return hv_status;
 59}
 60
 61typedef u64 (*hv_hypercall_f)(u64 control, u64 param1, u64 param2);
 62
 63static inline void hv_set_hypercall_pg(void *ptr)
 64{
 65	hv_hypercall_pg = ptr;
 66
 67	if (!ptr)
 68		ptr = &__hv_hyperfail;
 69	static_call_update(__hv_hypercall, (hv_hypercall_f)ptr);
 70}
 71#else
 72static inline void hv_set_hypercall_pg(void *ptr)
 73{
 74	hv_hypercall_pg = ptr;
 75}
 76EXPORT_SYMBOL_GPL(hv_hypercall_pg);
 77#endif
 78
 79union hv_ghcb * __percpu *hv_ghcb_pg;
 80
 81/* Storage to save the hypercall page temporarily for hibernation */
 82static void *hv_hypercall_pg_saved;
 83
 84struct hv_vp_assist_page **hv_vp_assist_page;
 85EXPORT_SYMBOL_GPL(hv_vp_assist_page);
 86
 87static int hyperv_init_ghcb(void)
 88{
 89	u64 ghcb_gpa;
 90	void *ghcb_va;
 91	void **ghcb_base;
 92
 93	if (!ms_hyperv.paravisor_present || !hv_isolation_type_snp())
 94		return 0;
 95
 96	if (!hv_ghcb_pg)
 97		return -EINVAL;
 98
 99	/*
100	 * GHCB page is allocated by paravisor. The address
101	 * returned by MSR_AMD64_SEV_ES_GHCB is above shared
102	 * memory boundary and map it here.
103	 */
104	rdmsrq(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
105
106	/* Mask out vTOM bit. ioremap_cache() maps decrypted */
107	ghcb_gpa &= ~ms_hyperv.shared_gpa_boundary;
108	ghcb_va = (void *)ioremap_cache(ghcb_gpa, HV_HYP_PAGE_SIZE);
109	if (!ghcb_va)
110		return -ENOMEM;
111
112	ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
113	*ghcb_base = ghcb_va;
114
115	return 0;
116}
117
118static int hv_cpu_init(unsigned int cpu)
119{
120	union hv_vp_assist_msr_contents msr = { 0 };
121	struct hv_vp_assist_page **hvp;
122	int ret;
123
124	ret = hv_common_cpu_init(cpu);
125	if (ret)
126		return ret;
127
128	if (!hv_vp_assist_page)
129		return 0;
130
131	hvp = &hv_vp_assist_page[cpu];
132	if (hv_root_partition()) {
133		/*
134		 * For root partition we get the hypervisor provided VP assist
135		 * page, instead of allocating a new page.
136		 */
137		rdmsrq(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
138		*hvp = memremap(msr.pfn << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT,
139				PAGE_SIZE, MEMREMAP_WB);
140	} else {
141		/*
142		 * The VP assist page is an "overlay" page (see Hyper-V TLFS's
143		 * Section 5.2.1 "GPA Overlay Pages"). Here it must be zeroed
144		 * out to make sure we always write the EOI MSR in
145		 * hv_apic_eoi_write() *after* the EOI optimization is disabled
146		 * in hv_cpu_die(), otherwise a CPU may not be stopped in the
147		 * case of CPU offlining and the VM will hang.
148		 */
149		if (!*hvp) {
150			*hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO);
151
152			/*
153			 * Hyper-V should never specify a VM that is a Confidential
154			 * VM and also running in the root partition. Root partition
155			 * is blocked to run in Confidential VM. So only decrypt assist
156			 * page in non-root partition here.
157			 */
158			if (*hvp && !ms_hyperv.paravisor_present && hv_isolation_type_snp()) {
159				WARN_ON_ONCE(set_memory_decrypted((unsigned long)(*hvp), 1));
160				memset(*hvp, 0, PAGE_SIZE);
161			}
162		}
163
164		if (*hvp)
165			msr.pfn = vmalloc_to_pfn(*hvp);
166
167	}
168	if (!WARN_ON(!(*hvp))) {
169		msr.enable = 1;
170		wrmsrq(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
171	}
172
173	/* Allow Hyper-V stimer vector to be injected from Hypervisor. */
174	if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE)
175		apic_update_vector(cpu, HYPERV_STIMER0_VECTOR, true);
176
177	return hyperv_init_ghcb();
178}
179
180static void (*hv_reenlightenment_cb)(void);
181
182static void hv_reenlightenment_notify(struct work_struct *dummy)
183{
184	struct hv_tsc_emulation_status emu_status;
185
186	rdmsrq(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
187
188	/* Don't issue the callback if TSC accesses are not emulated */
189	if (hv_reenlightenment_cb && emu_status.inprogress)
190		hv_reenlightenment_cb();
191}
192static DECLARE_DELAYED_WORK(hv_reenlightenment_work, hv_reenlightenment_notify);
193
194void hyperv_stop_tsc_emulation(void)
195{
196	u64 freq;
197	struct hv_tsc_emulation_status emu_status;
198
199	rdmsrq(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
200	emu_status.inprogress = 0;
201	wrmsrq(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
202
203	rdmsrq(HV_X64_MSR_TSC_FREQUENCY, freq);
204	tsc_khz = div64_u64(freq, 1000);
205}
206EXPORT_SYMBOL_GPL(hyperv_stop_tsc_emulation);
207
208static inline bool hv_reenlightenment_available(void)
209{
210	/*
211	 * Check for required features and privileges to make TSC frequency
212	 * change notifications work.
213	 */
214	return ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
215		ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE &&
216		ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT;
217}
218
219DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_reenlightenment)
220{
221	apic_eoi();
222	inc_irq_stat(irq_hv_reenlightenment_count);
223	schedule_delayed_work(&hv_reenlightenment_work, HZ/10);
224}
225
226void set_hv_tscchange_cb(void (*cb)(void))
227{
228	struct hv_reenlightenment_control re_ctrl = {
229		.vector = HYPERV_REENLIGHTENMENT_VECTOR,
230		.enabled = 1,
231	};
232	struct hv_tsc_emulation_control emu_ctrl = {.enabled = 1};
233
234	if (!hv_reenlightenment_available()) {
235		pr_warn("reenlightenment support is unavailable\n");
236		return;
237	}
238
239	if (!hv_vp_index)
240		return;
241
242	hv_reenlightenment_cb = cb;
243
244	/* Make sure callback is registered before we write to MSRs */
245	wmb();
246
247	re_ctrl.target_vp = hv_vp_index[get_cpu()];
248
249	wrmsrq(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
250	wrmsrq(HV_X64_MSR_TSC_EMULATION_CONTROL, *((u64 *)&emu_ctrl));
251
252	put_cpu();
253}
254EXPORT_SYMBOL_GPL(set_hv_tscchange_cb);
255
256void clear_hv_tscchange_cb(void)
257{
258	struct hv_reenlightenment_control re_ctrl;
259
260	if (!hv_reenlightenment_available())
261		return;
262
263	rdmsrq(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
264	re_ctrl.enabled = 0;
265	wrmsrq(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
266
267	hv_reenlightenment_cb = NULL;
268}
269EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb);
270
271static int hv_cpu_die(unsigned int cpu)
272{
273	struct hv_reenlightenment_control re_ctrl;
274	unsigned int new_cpu;
275	void **ghcb_va;
276
277	if (hv_ghcb_pg) {
278		ghcb_va = (void **)this_cpu_ptr(hv_ghcb_pg);
279		if (*ghcb_va)
280			iounmap(*ghcb_va);
281		*ghcb_va = NULL;
282	}
283
284	if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE)
285		apic_update_vector(cpu, HYPERV_STIMER0_VECTOR, false);
286
287	hv_common_cpu_die(cpu);
288
289	if (hv_vp_assist_page && hv_vp_assist_page[cpu]) {
290		union hv_vp_assist_msr_contents msr = { 0 };
291		if (hv_root_partition()) {
292			/*
293			 * For root partition the VP assist page is mapped to
294			 * hypervisor provided page, and thus we unmap the
295			 * page here and nullify it, so that in future we have
296			 * correct page address mapped in hv_cpu_init.
297			 */
298			memunmap(hv_vp_assist_page[cpu]);
299			hv_vp_assist_page[cpu] = NULL;
300			rdmsrq(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
301			msr.enable = 0;
302		}
303		wrmsrq(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
304	}
305
306	if (hv_reenlightenment_cb == NULL)
307		return 0;
308
309	rdmsrq(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
310	if (re_ctrl.target_vp == hv_vp_index[cpu]) {
311		/*
312		 * Reassign reenlightenment notifications to some other online
313		 * CPU or just disable the feature if there are no online CPUs
314		 * left (happens on hibernation).
315		 */
316		new_cpu = cpumask_any_but(cpu_online_mask, cpu);
317
318		if (new_cpu < nr_cpu_ids)
319			re_ctrl.target_vp = hv_vp_index[new_cpu];
320		else
321			re_ctrl.enabled = 0;
322
323		wrmsrq(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
324	}
325
326	return 0;
327}
328
329static int __init hv_pci_init(void)
330{
331	bool gen2vm = efi_enabled(EFI_BOOT);
332
333	/*
334	 * A Generation-2 VM doesn't support legacy PCI/PCIe, so both
335	 * raw_pci_ops and raw_pci_ext_ops are NULL, and pci_subsys_init() ->
336	 * pcibios_init() doesn't call pcibios_resource_survey() ->
337	 * e820__reserve_resources_late(); as a result, any emulated persistent
338	 * memory of E820_TYPE_PRAM (12) via the kernel parameter
339	 * memmap=nn[KMG]!ss is not added into iomem_resource and hence can't be
340	 * detected by register_e820_pmem(). Fix this by directly calling
341	 * e820__reserve_resources_late() here: e820__reserve_resources_late()
342	 * depends on e820__reserve_resources(), which has been called earlier
343	 * from setup_arch(). Note: e820__reserve_resources_late() also adds
344	 * any memory of E820_TYPE_PMEM (7) into iomem_resource, and
345	 * acpi_nfit_register_region() -> acpi_nfit_insert_resource() ->
346	 * region_intersects() returns REGION_INTERSECTS, so the memory of
347	 * E820_TYPE_PMEM won't get added twice.
348	 *
349	 * We return 0 here so that pci_arch_init() won't print the warning:
350	 * "PCI: Fatal: No config space access function found"
351	 */
352	if (gen2vm) {
353		e820__reserve_resources_late();
354		return 0;
355	}
356
357	/* For Generation-1 VM, we'll proceed in pci_arch_init().  */
358	return 1;
359}
360
361static int hv_suspend(void *data)
362{
363	union hv_x64_msr_hypercall_contents hypercall_msr;
364	int ret;
365
366	if (hv_root_partition())
367		return -EPERM;
368
369	/*
370	 * Reset the hypercall page as it is going to be invalidated
371	 * across hibernation. Setting hv_hypercall_pg to NULL ensures
372	 * that any subsequent hypercall operation fails safely instead of
373	 * crashing due to an access of an invalid page. The hypercall page
374	 * pointer is restored on resume.
375	 */
376	hv_hypercall_pg_saved = hv_hypercall_pg;
377	hv_set_hypercall_pg(NULL);
378
379	/* Disable the hypercall page in the hypervisor */
380	rdmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
381	hypercall_msr.enable = 0;
382	wrmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
383
384	ret = hv_cpu_die(0);
385	return ret;
386}
387
388static void hv_resume(void *data)
389{
390	union hv_x64_msr_hypercall_contents hypercall_msr;
391	int ret;
392
393	ret = hv_cpu_init(0);
394	WARN_ON(ret);
395
396	/* Re-enable the hypercall page */
397	rdmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
398	hypercall_msr.enable = 1;
399	hypercall_msr.guest_physical_address =
400		vmalloc_to_pfn(hv_hypercall_pg_saved);
401	wrmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
402
403	hv_set_hypercall_pg(hv_hypercall_pg_saved);
404	hv_hypercall_pg_saved = NULL;
405
406	/*
407	 * Reenlightenment notifications are disabled by hv_cpu_die(0),
408	 * reenable them here if hv_reenlightenment_cb was previously set.
409	 */
410	if (hv_reenlightenment_cb)
411		set_hv_tscchange_cb(hv_reenlightenment_cb);
412}
413
414/* Note: when the ops are called, only CPU0 is online and IRQs are disabled. */
415static const struct syscore_ops hv_syscore_ops = {
416	.suspend	= hv_suspend,
417	.resume		= hv_resume,
418};
419
420static struct syscore hv_syscore = {
421	.ops = &hv_syscore_ops,
422};
423
424static void (* __initdata old_setup_percpu_clockev)(void);
425
426static void __init hv_stimer_setup_percpu_clockev(void)
427{
428	/*
429	 * Ignore any errors in setting up stimer clockevents
430	 * as we can run with the LAPIC timer as a fallback.
431	 */
432	(void)hv_stimer_alloc(false);
433
434	/*
435	 * Still register the LAPIC timer, because the direct-mode STIMER is
436	 * not supported by old versions of Hyper-V. This also allows users
437	 * to switch to LAPIC timer via /sys, if they want to.
438	 */
439	if (old_setup_percpu_clockev)
440		old_setup_percpu_clockev();
441}
442
443/*
444 * This function is to be invoked early in the boot sequence after the
445 * hypervisor has been detected.
446 *
447 * 1. Setup the hypercall page.
448 * 2. Register Hyper-V specific clocksource.
449 * 3. Setup Hyper-V specific APIC entry points.
450 */
451void __init hyperv_init(void)
452{
453	u64 guest_id;
454	union hv_x64_msr_hypercall_contents hypercall_msr;
455	int cpuhp;
456
457	if (x86_hyper_type != X86_HYPER_MS_HYPERV)
458		return;
459
460	if (hv_common_init())
461		return;
462
463	/*
464	 * The VP assist page is useless to a TDX guest: the only use we
465	 * would have for it is lazy EOI, which can not be used with TDX.
466	 */
467	if (hv_isolation_type_tdx())
468		hv_vp_assist_page = NULL;
469	else
470		hv_vp_assist_page = kcalloc(nr_cpu_ids,
471					    sizeof(*hv_vp_assist_page),
472					    GFP_KERNEL);
473	if (!hv_vp_assist_page) {
474		ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
475
476		if (!hv_isolation_type_tdx())
477			goto common_free;
478	}
479
480	if (ms_hyperv.paravisor_present && hv_isolation_type_snp()) {
481		/* Negotiate GHCB Version. */
482		if (!hv_ghcb_negotiate_protocol())
483			hv_ghcb_terminate(SEV_TERM_SET_GEN,
484					  GHCB_SEV_ES_PROT_UNSUPPORTED);
485
486		hv_ghcb_pg = alloc_percpu(union hv_ghcb *);
487		if (!hv_ghcb_pg)
488			goto free_vp_assist_page;
489	}
490
491	cpuhp = cpuhp_setup_state(CPUHP_AP_HYPERV_ONLINE, "x86/hyperv_init:online",
492				  hv_cpu_init, hv_cpu_die);
493	if (cpuhp < 0)
494		goto free_ghcb_page;
495
496	/*
497	 * Setup the hypercall page and enable hypercalls.
498	 * 1. Register the guest ID
499	 * 2. Enable the hypercall and register the hypercall page
500	 *
501	 * A TDX VM with no paravisor only uses TDX GHCI rather than hv_hypercall_pg:
502	 * when the hypercall input is a page, such a VM must pass a decrypted
503	 * page to Hyper-V, e.g. hv_post_message() uses the per-CPU page
504	 * hyperv_pcpu_input_arg, which is decrypted if no paravisor is present.
505	 *
506	 * A TDX VM with the paravisor uses hv_hypercall_pg for most hypercalls,
507	 * which are handled by the paravisor and the VM must use an encrypted
508	 * input page: in such a VM, the hyperv_pcpu_input_arg is encrypted and
509	 * used in the hypercalls, e.g. see hv_mark_gpa_visibility() and
510	 * hv_arch_irq_unmask(). Such a VM uses TDX GHCI for two hypercalls:
511	 * 1. HVCALL_SIGNAL_EVENT: see vmbus_set_event() and _hv_do_fast_hypercall8().
512	 * 2. HVCALL_POST_MESSAGE: the input page must be a decrypted page, i.e.
513	 * hv_post_message() in such a VM can't use the encrypted hyperv_pcpu_input_arg;
514	 * instead, hv_post_message() uses the post_msg_page, which is decrypted
515	 * in such a VM and is only used in such a VM.
516	 */
517	guest_id = hv_generate_guest_id(LINUX_VERSION_CODE);
518	wrmsrq(HV_X64_MSR_GUEST_OS_ID, guest_id);
519
520	/* With the paravisor, the VM must also write the ID via GHCB/GHCI */
521	hv_ivm_msr_write(HV_X64_MSR_GUEST_OS_ID, guest_id);
522
523	/* A TDX VM with no paravisor only uses TDX GHCI rather than hv_hypercall_pg */
524	if (hv_isolation_type_tdx() && !ms_hyperv.paravisor_present)
525		goto skip_hypercall_pg_init;
526
527	hv_hypercall_pg = __vmalloc_node_range(PAGE_SIZE, 1, MODULES_VADDR,
528			MODULES_END, GFP_KERNEL, PAGE_KERNEL_ROX,
529			VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
530			__builtin_return_address(0));
531	if (hv_hypercall_pg == NULL)
532		goto clean_guest_os_id;
533
534	rdmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
535	hypercall_msr.enable = 1;
536
537	if (hv_root_partition()) {
538		struct page *pg;
539		void *src;
540
541		/*
542		 * For the root partition, the hypervisor will set up its
543		 * hypercall page. The hypervisor guarantees it will not show
544		 * up in the root's address space. The root can't change the
545		 * location of the hypercall page.
546		 *
547		 * Order is important here. We must enable the hypercall page
548		 * so it is populated with code, then copy the code to an
549		 * executable page.
550		 */
551		wrmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
552
553		pg = vmalloc_to_page(hv_hypercall_pg);
554		src = memremap(hypercall_msr.guest_physical_address << PAGE_SHIFT, PAGE_SIZE,
555				MEMREMAP_WB);
556		BUG_ON(!src);
557		memcpy_to_page(pg, 0, src, HV_HYP_PAGE_SIZE);
558		memunmap(src);
559
560		hv_remap_tsc_clocksource();
561		hv_sleep_notifiers_register();
562	} else {
563		hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
564		wrmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
565	}
566
567	hv_set_hypercall_pg(hv_hypercall_pg);
568
569	if (hv_root_partition())        /* after set hypercall pg */
570		hv_root_crash_init();
571
572skip_hypercall_pg_init:
573	/*
574	 * hyperv_init() is called before LAPIC is initialized: see
575	 * apic_intr_mode_init() -> x86_platform.apic_post_init() and
576	 * apic_bsp_setup() -> setup_local_APIC(). The direct-mode STIMER
577	 * depends on LAPIC, so hv_stimer_alloc() should be called from
578	 * x86_init.timers.setup_percpu_clockev.
579	 */
580	old_setup_percpu_clockev = x86_init.timers.setup_percpu_clockev;
581	x86_init.timers.setup_percpu_clockev = hv_stimer_setup_percpu_clockev;
582
583	hv_apic_init();
584
585	x86_init.pci.arch_init = hv_pci_init;
586
587	register_syscore(&hv_syscore);
588
589	if (ms_hyperv.priv_high & HV_ACCESS_PARTITION_ID)
590		hv_get_partition_id();
591
592#ifdef CONFIG_PCI_MSI
593	/*
594	 * If we're running as root, we want to create our own PCI MSI domain.
595	 * We can't set this in hv_pci_init because that would be too late.
596	 */
597	if (hv_root_partition())
598		x86_init.irqs.create_pci_msi_domain = hv_create_pci_msi_domain;
599#endif
600
601	/* Query the VMs extended capability once, so that it can be cached. */
602	hv_query_ext_cap(0);
603
604	/* Find the VTL */
605	ms_hyperv.vtl = get_vtl();
606
607	if (ms_hyperv.vtl > 0) /* non default VTL */
608		hv_vtl_early_init();
609
610	return;
611
612clean_guest_os_id:
613	wrmsrq(HV_X64_MSR_GUEST_OS_ID, 0);
614	hv_ivm_msr_write(HV_X64_MSR_GUEST_OS_ID, 0);
615	cpuhp_remove_state(CPUHP_AP_HYPERV_ONLINE);
616free_ghcb_page:
617	free_percpu(hv_ghcb_pg);
618free_vp_assist_page:
619	kfree(hv_vp_assist_page);
620	hv_vp_assist_page = NULL;
621common_free:
622	hv_common_free();
623}
624
625/*
626 * This routine is called before kexec/kdump, it does the required cleanup.
627 */
628void hyperv_cleanup(void)
629{
630	union hv_x64_msr_hypercall_contents hypercall_msr;
631	union hv_reference_tsc_msr tsc_msr;
632
633	/* Reset our OS id */
634	wrmsrq(HV_X64_MSR_GUEST_OS_ID, 0);
635	hv_ivm_msr_write(HV_X64_MSR_GUEST_OS_ID, 0);
636
637	/*
638	 * Reset hypercall page reference before reset the page,
639	 * let hypercall operations fail safely rather than
640	 * panic the kernel for using invalid hypercall page
641	 */
642	hv_hypercall_pg = NULL;
643
644	/* Reset the hypercall page */
645	hypercall_msr.as_uint64 = hv_get_msr(HV_X64_MSR_HYPERCALL);
646	hypercall_msr.enable = 0;
647	hv_set_msr(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
648
649	/* Reset the TSC page */
650	tsc_msr.as_uint64 = hv_get_msr(HV_X64_MSR_REFERENCE_TSC);
651	tsc_msr.enable = 0;
652	hv_set_msr(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
653}
654
655void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die)
656{
657	static bool panic_reported;
658	u64 guest_id;
659
660	if (in_die && !panic_on_oops)
661		return;
662
663	/*
664	 * We prefer to report panic on 'die' chain as we have proper
665	 * registers to report, but if we miss it (e.g. on BUG()) we need
666	 * to report it on 'panic'.
667	 */
668	if (panic_reported)
669		return;
670	panic_reported = true;
671
672	rdmsrq(HV_X64_MSR_GUEST_OS_ID, guest_id);
673
674	wrmsrq(HV_X64_MSR_CRASH_P0, err);
675	wrmsrq(HV_X64_MSR_CRASH_P1, guest_id);
676	wrmsrq(HV_X64_MSR_CRASH_P2, regs->ip);
677	wrmsrq(HV_X64_MSR_CRASH_P3, regs->ax);
678	wrmsrq(HV_X64_MSR_CRASH_P4, regs->sp);
679
680	/*
681	 * Let Hyper-V know there is crash data available
682	 */
683	wrmsrq(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
684}
685EXPORT_SYMBOL_GPL(hyperv_report_panic);
686
687bool hv_is_hyperv_initialized(void)
688{
689	union hv_x64_msr_hypercall_contents hypercall_msr;
690
691	/*
692	 * Ensure that we're really on Hyper-V, and not a KVM or Xen
693	 * emulation of Hyper-V
694	 */
695	if (x86_hyper_type != X86_HYPER_MS_HYPERV)
696		return false;
697
698	/* A TDX VM with no paravisor uses TDX GHCI call rather than hv_hypercall_pg */
699	if (hv_isolation_type_tdx() && !ms_hyperv.paravisor_present)
700		return true;
701	/*
702	 * Verify that earlier initialization succeeded by checking
703	 * that the hypercall page is setup
704	 */
705	hypercall_msr.as_uint64 = 0;
706	rdmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
707
708	return hypercall_msr.enable;
709}
710EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);
711
712int hv_apicid_to_vp_index(u32 apic_id)
713{
714	u64 control;
715	u64 status;
716	unsigned long irq_flags;
717	struct hv_get_vp_from_apic_id_in *input;
718	u32 *output, ret;
719
720	local_irq_save(irq_flags);
721
722	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
723	memset(input, 0, sizeof(*input));
724	input->partition_id = HV_PARTITION_ID_SELF;
725	input->apic_ids[0] = apic_id;
726
727	output = *this_cpu_ptr(hyperv_pcpu_output_arg);
728
729	control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_INDEX_FROM_APIC_ID;
730	status = hv_do_hypercall(control, input, output);
731	ret = output[0];
732
733	local_irq_restore(irq_flags);
734
735	if (!hv_result_success(status)) {
736		pr_err("failed to get vp index from apic id %d, status %#llx\n",
737		       apic_id, status);
738		return -EINVAL;
739	}
740
741	return ret;
742}
743EXPORT_SYMBOL_GPL(hv_apicid_to_vp_index);