Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0-only
2 : /*
3 : * HyperV Detection code.
4 : *
5 : * Copyright (C) 2010, Novell, Inc.
6 : * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
7 : */
8 :
9 : #include <linux/types.h>
10 : #include <linux/time.h>
11 : #include <linux/clocksource.h>
12 : #include <linux/init.h>
13 : #include <linux/export.h>
14 : #include <linux/hardirq.h>
15 : #include <linux/efi.h>
16 : #include <linux/interrupt.h>
17 : #include <linux/irq.h>
18 : #include <linux/kexec.h>
19 : #include <linux/i8253.h>
20 : #include <linux/random.h>
21 : #include <asm/processor.h>
22 : #include <asm/hypervisor.h>
23 : #include <asm/hyperv-tlfs.h>
24 : #include <asm/mshyperv.h>
25 : #include <asm/desc.h>
26 : #include <asm/idtentry.h>
27 : #include <asm/irq_regs.h>
28 : #include <asm/i8259.h>
29 : #include <asm/apic.h>
30 : #include <asm/timer.h>
31 : #include <asm/reboot.h>
32 : #include <asm/nmi.h>
33 : #include <clocksource/hyperv_timer.h>
34 : #include <asm/numa.h>
35 :
36 : /* Is Linux running as the root partition? */
37 : bool hv_root_partition;
38 : EXPORT_SYMBOL_GPL(hv_root_partition);
39 :
40 : struct ms_hyperv_info ms_hyperv;
41 : EXPORT_SYMBOL_GPL(ms_hyperv);
42 :
43 : #if IS_ENABLED(CONFIG_HYPERV)
44 : static void (*vmbus_handler)(void);
45 : static void (*hv_stimer0_handler)(void);
46 : static void (*hv_kexec_handler)(void);
47 : static void (*hv_crash_handler)(struct pt_regs *regs);
48 :
49 : DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_callback)
50 : {
51 : struct pt_regs *old_regs = set_irq_regs(regs);
52 :
53 : inc_irq_stat(irq_hv_callback_count);
54 : if (vmbus_handler)
55 : vmbus_handler();
56 :
57 : if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED)
58 : ack_APIC_irq();
59 :
60 : set_irq_regs(old_regs);
61 : }
62 :
63 : int hv_setup_vmbus_irq(int irq, void (*handler)(void))
64 : {
65 : /*
66 : * The 'irq' argument is ignored on x86/x64 because a hard-coded
67 : * interrupt vector is used for Hyper-V interrupts.
68 : */
69 : vmbus_handler = handler;
70 : return 0;
71 : }
72 :
73 : void hv_remove_vmbus_irq(void)
74 : {
75 : /* We have no way to deallocate the interrupt gate */
76 : vmbus_handler = NULL;
77 : }
78 : EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq);
79 : EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);
80 :
81 : /*
82 : * Routines to do per-architecture handling of stimer0
83 : * interrupts when in Direct Mode
84 : */
85 : DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_stimer0)
86 : {
87 : struct pt_regs *old_regs = set_irq_regs(regs);
88 :
89 : inc_irq_stat(hyperv_stimer0_count);
90 : if (hv_stimer0_handler)
91 : hv_stimer0_handler();
92 : add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0);
93 : ack_APIC_irq();
94 :
95 : set_irq_regs(old_regs);
96 : }
97 :
98 : int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void))
99 : {
100 : *vector = HYPERV_STIMER0_VECTOR;
101 : *irq = -1; /* Unused on x86/x64 */
102 : hv_stimer0_handler = handler;
103 : return 0;
104 : }
105 : EXPORT_SYMBOL_GPL(hv_setup_stimer0_irq);
106 :
107 : void hv_remove_stimer0_irq(int irq)
108 : {
109 : /* We have no way to deallocate the interrupt gate */
110 : hv_stimer0_handler = NULL;
111 : }
112 : EXPORT_SYMBOL_GPL(hv_remove_stimer0_irq);
113 :
114 : void hv_setup_kexec_handler(void (*handler)(void))
115 : {
116 : hv_kexec_handler = handler;
117 : }
118 : EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
119 :
120 : void hv_remove_kexec_handler(void)
121 : {
122 : hv_kexec_handler = NULL;
123 : }
124 : EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
125 :
126 : void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
127 : {
128 : hv_crash_handler = handler;
129 : }
130 : EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
131 :
132 : void hv_remove_crash_handler(void)
133 : {
134 : hv_crash_handler = NULL;
135 : }
136 : EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
137 :
138 : #ifdef CONFIG_KEXEC_CORE
139 : static void hv_machine_shutdown(void)
140 : {
141 : if (kexec_in_progress && hv_kexec_handler)
142 : hv_kexec_handler();
143 :
144 : /*
145 : * Call hv_cpu_die() on all the CPUs, otherwise later the hypervisor
146 : * corrupts the old VP Assist Pages and can crash the kexec kernel.
147 : */
148 : if (kexec_in_progress && hyperv_init_cpuhp > 0)
149 : cpuhp_remove_state(hyperv_init_cpuhp);
150 :
151 : /* The function calls stop_other_cpus(). */
152 : native_machine_shutdown();
153 :
154 : /* Disable the hypercall page when there is only 1 active CPU. */
155 : if (kexec_in_progress)
156 : hyperv_cleanup();
157 : }
158 :
159 : static void hv_machine_crash_shutdown(struct pt_regs *regs)
160 : {
161 : if (hv_crash_handler)
162 : hv_crash_handler(regs);
163 :
164 : /* The function calls crash_smp_send_stop(). */
165 : native_machine_crash_shutdown(regs);
166 :
167 : /* Disable the hypercall page when there is only 1 active CPU. */
168 : hyperv_cleanup();
169 : }
170 : #endif /* CONFIG_KEXEC_CORE */
171 : #endif /* CONFIG_HYPERV */
172 :
173 1 : static uint32_t __init ms_hyperv_platform(void)
174 : {
175 1 : u32 eax;
176 1 : u32 hyp_signature[3];
177 :
178 1 : if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
179 : return 0;
180 :
181 1 : cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
182 : &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
183 :
184 1 : if (eax >= HYPERV_CPUID_MIN &&
185 0 : eax <= HYPERV_CPUID_MAX &&
186 0 : !memcmp("Microsoft Hv", hyp_signature, 12))
187 0 : return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
188 :
189 : return 0;
190 : }
191 :
192 : static unsigned char hv_get_nmi_reason(void)
193 : {
194 : return 0;
195 : }
196 :
197 : #ifdef CONFIG_X86_LOCAL_APIC
198 : /*
199 : * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes
200 : * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle
201 : * unknown NMI on the first CPU which gets it.
202 : */
203 0 : static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs)
204 : {
205 0 : static atomic_t nmi_cpu = ATOMIC_INIT(-1);
206 :
207 0 : if (!unknown_nmi_panic)
208 : return NMI_DONE;
209 :
210 0 : if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1)
211 0 : return NMI_HANDLED;
212 :
213 : return NMI_DONE;
214 : }
215 : #endif
216 :
217 0 : static unsigned long hv_get_tsc_khz(void)
218 : {
219 0 : unsigned long freq;
220 :
221 0 : rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
222 :
223 0 : return freq / 1000;
224 : }
225 :
226 : #if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV)
227 : static void __init hv_smp_prepare_boot_cpu(void)
228 : {
229 : native_smp_prepare_boot_cpu();
230 : #if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS)
231 : hv_init_spinlocks();
232 : #endif
233 : }
234 :
235 : static void __init hv_smp_prepare_cpus(unsigned int max_cpus)
236 : {
237 : #ifdef CONFIG_X86_64
238 : int i;
239 : int ret;
240 : #endif
241 :
242 : native_smp_prepare_cpus(max_cpus);
243 :
244 : #ifdef CONFIG_X86_64
245 : for_each_present_cpu(i) {
246 : if (i == 0)
247 : continue;
248 : ret = hv_call_add_logical_proc(numa_cpu_node(i), i, cpu_physical_id(i));
249 : BUG_ON(ret);
250 : }
251 :
252 : for_each_present_cpu(i) {
253 : if (i == 0)
254 : continue;
255 : ret = hv_call_create_vp(numa_cpu_node(i), hv_current_partition_id, i, i);
256 : BUG_ON(ret);
257 : }
258 : #endif
259 : }
260 : #endif
261 :
262 0 : static void __init ms_hyperv_init_platform(void)
263 : {
264 0 : int hv_host_info_eax;
265 0 : int hv_host_info_ebx;
266 0 : int hv_host_info_ecx;
267 0 : int hv_host_info_edx;
268 :
269 : #ifdef CONFIG_PARAVIRT
270 0 : pv_info.name = "Hyper-V";
271 : #endif
272 :
273 : /*
274 : * Extract the features and hints
275 : */
276 0 : ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
277 0 : ms_hyperv.features_b = cpuid_ebx(HYPERV_CPUID_FEATURES);
278 0 : ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
279 0 : ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
280 :
281 0 : pr_info("Hyper-V: features 0x%x, hints 0x%x, misc 0x%x\n",
282 : ms_hyperv.features, ms_hyperv.hints, ms_hyperv.misc_features);
283 :
284 0 : ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS);
285 0 : ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS);
286 :
287 0 : pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n",
288 : ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);
289 :
290 : /*
291 : * Check CPU management privilege.
292 : *
293 : * To mirror what Windows does we should extract CPU management
294 : * features and use the ReservedIdentityBit to detect if Linux is the
295 : * root partition. But that requires negotiating CPU management
296 : * interface (a process to be finalized).
297 : *
298 : * For now, use the privilege flag as the indicator for running as
299 : * root.
300 : */
301 0 : if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_CPU_MANAGEMENT) {
302 0 : hv_root_partition = true;
303 0 : pr_info("Hyper-V: running as root partition\n");
304 : }
305 :
306 : /*
307 : * Extract host information.
308 : */
309 0 : if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >=
310 : HYPERV_CPUID_VERSION) {
311 0 : hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION);
312 0 : hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION);
313 0 : hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION);
314 0 : hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION);
315 :
316 0 : pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n",
317 : hv_host_info_eax, hv_host_info_ebx >> 16,
318 : hv_host_info_ebx & 0xFFFF, hv_host_info_ecx,
319 : hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF);
320 : }
321 :
322 0 : if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
323 0 : ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
324 0 : x86_platform.calibrate_tsc = hv_get_tsc_khz;
325 0 : x86_platform.calibrate_cpu = hv_get_tsc_khz;
326 : }
327 :
328 0 : if (ms_hyperv.features_b & HV_ISOLATION) {
329 0 : ms_hyperv.isolation_config_a = cpuid_eax(HYPERV_CPUID_ISOLATION_CONFIG);
330 0 : ms_hyperv.isolation_config_b = cpuid_ebx(HYPERV_CPUID_ISOLATION_CONFIG);
331 :
332 0 : pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",
333 : ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);
334 : }
335 :
336 0 : if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) {
337 0 : ms_hyperv.nested_features =
338 0 : cpuid_eax(HYPERV_CPUID_NESTED_FEATURES);
339 : }
340 :
341 : /*
342 : * Hyper-V expects to get crash register data or kmsg when
343 : * crash enlightment is available and system crashes. Set
344 : * crash_kexec_post_notifiers to be true to make sure that
345 : * calling crash enlightment interface before running kdump
346 : * kernel.
347 : */
348 0 : if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE)
349 0 : crash_kexec_post_notifiers = true;
350 :
351 : #ifdef CONFIG_X86_LOCAL_APIC
352 0 : if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
353 : ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
354 : /*
355 : * Get the APIC frequency.
356 : */
357 0 : u64 hv_lapic_frequency;
358 :
359 0 : rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
360 0 : hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
361 0 : lapic_timer_period = hv_lapic_frequency;
362 0 : pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n",
363 : lapic_timer_period);
364 : }
365 :
366 0 : register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST,
367 : "hv_nmi_unknown");
368 : #endif
369 :
370 : #ifdef CONFIG_X86_IO_APIC
371 0 : no_timer_check = 1;
372 : #endif
373 :
374 : #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE)
375 : machine_ops.shutdown = hv_machine_shutdown;
376 : machine_ops.crash_shutdown = hv_machine_crash_shutdown;
377 : #endif
378 0 : if (ms_hyperv.features & HV_ACCESS_TSC_INVARIANT) {
379 0 : wrmsrl(HV_X64_MSR_TSC_INVARIANT_CONTROL, 0x1);
380 0 : setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
381 : } else {
382 0 : mark_tsc_unstable("running on Hyper-V");
383 : }
384 :
385 : /*
386 : * Generation 2 instances don't support reading the NMI status from
387 : * 0x61 port.
388 : */
389 0 : if (efi_enabled(EFI_BOOT))
390 : x86_platform.get_nmi_reason = hv_get_nmi_reason;
391 :
392 : /*
393 : * Hyper-V VMs have a PIT emulation quirk such that zeroing the
394 : * counter register during PIT shutdown restarts the PIT. So it
395 : * continues to interrupt @18.2 HZ. Setting i8253_clear_counter
396 : * to false tells pit_shutdown() not to zero the counter so that
397 : * the PIT really is shutdown. Generation 2 VMs don't have a PIT,
398 : * and setting this value has no effect.
399 : */
400 0 : i8253_clear_counter_on_shutdown = false;
401 :
402 : #if IS_ENABLED(CONFIG_HYPERV)
403 : /*
404 : * Setup the hook to get control post apic initialization.
405 : */
406 : x86_platform.apic_post_init = hyperv_init;
407 : hyperv_setup_mmu_ops();
408 : /* Setup the IDT for hypervisor callback */
409 : alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_hyperv_callback);
410 :
411 : /* Setup the IDT for reenlightenment notifications */
412 : if (ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT) {
413 : alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR,
414 : asm_sysvec_hyperv_reenlightenment);
415 : }
416 :
417 : /* Setup the IDT for stimer0 */
418 : if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) {
419 : alloc_intr_gate(HYPERV_STIMER0_VECTOR,
420 : asm_sysvec_hyperv_stimer0);
421 : }
422 :
423 : # ifdef CONFIG_SMP
424 : smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu;
425 : if (hv_root_partition)
426 : smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus;
427 : # endif
428 :
429 : /*
430 : * Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic,
431 : * set x2apic destination mode to physcial mode when x2apic is available
432 : * and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs
433 : * have 8-bit APIC id.
434 : */
435 : # ifdef CONFIG_X86_X2APIC
436 : if (x2apic_supported())
437 : x2apic_phys = 1;
438 : # endif
439 :
440 : /* Register Hyper-V specific clocksource */
441 : hv_init_clocksource();
442 : #endif
443 0 : }
444 :
445 0 : static bool __init ms_hyperv_x2apic_available(void)
446 : {
447 0 : return x2apic_supported();
448 : }
449 :
450 : /*
451 : * If ms_hyperv_msi_ext_dest_id() returns true, hyperv_prepare_irq_remapping()
452 : * returns -ENODEV and the Hyper-V IOMMU driver is not used; instead, the
453 : * generic support of the 15-bit APIC ID is used: see __irq_msi_compose_msg().
454 : *
455 : * Note: for a VM on Hyper-V, the I/O-APIC is the only device which
456 : * (logically) generates MSIs directly to the system APIC irq domain.
457 : * There is no HPET, and PCI MSI/MSI-X interrupts are remapped by the
458 : * pci-hyperv host bridge.
459 : */
460 0 : static bool __init ms_hyperv_msi_ext_dest_id(void)
461 : {
462 0 : u32 eax;
463 :
464 0 : eax = cpuid_eax(HYPERV_CPUID_VIRT_STACK_INTERFACE);
465 0 : if (eax != HYPERV_VS_INTERFACE_EAX_SIGNATURE)
466 : return false;
467 :
468 0 : eax = cpuid_eax(HYPERV_CPUID_VIRT_STACK_PROPERTIES);
469 0 : return eax & HYPERV_VS_PROPERTIES_EAX_EXTENDED_IOAPIC_RTE;
470 : }
471 :
472 : const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
473 : .name = "Microsoft Hyper-V",
474 : .detect = ms_hyperv_platform,
475 : .type = X86_HYPER_MS_HYPERV,
476 : .init.x2apic_available = ms_hyperv_x2apic_available,
477 : .init.msi_ext_dest_id = ms_hyperv_msi_ext_dest_id,
478 : .init.init_platform = ms_hyperv_init_platform,
479 : };
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