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
35 struct ms_hyperv_info ms_hyperv;
36 EXPORT_SYMBOL_GPL(ms_hyperv);
37
38 #if IS_ENABLED(CONFIG_HYPERV)
39 static void (*vmbus_handler)(void);
40 static void (*hv_stimer0_handler)(void);
41 static void (*hv_kexec_handler)(void);
42 static void (*hv_crash_handler)(struct pt_regs *regs);
43
DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_callback)44 DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_callback)
45 {
46 struct pt_regs *old_regs = set_irq_regs(regs);
47
48 inc_irq_stat(irq_hv_callback_count);
49 if (vmbus_handler)
50 vmbus_handler();
51
52 if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED)
53 ack_APIC_irq();
54
55 set_irq_regs(old_regs);
56 }
57
hv_setup_vmbus_irq(int irq,void (* handler)(void))58 int hv_setup_vmbus_irq(int irq, void (*handler)(void))
59 {
60 /*
61 * The 'irq' argument is ignored on x86/x64 because a hard-coded
62 * interrupt vector is used for Hyper-V interrupts.
63 */
64 vmbus_handler = handler;
65 return 0;
66 }
67
hv_remove_vmbus_irq(void)68 void hv_remove_vmbus_irq(void)
69 {
70 /* We have no way to deallocate the interrupt gate */
71 vmbus_handler = NULL;
72 }
73 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq);
74 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);
75
76 /*
77 * Routines to do per-architecture handling of stimer0
78 * interrupts when in Direct Mode
79 */
DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_stimer0)80 DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_stimer0)
81 {
82 struct pt_regs *old_regs = set_irq_regs(regs);
83
84 inc_irq_stat(hyperv_stimer0_count);
85 if (hv_stimer0_handler)
86 hv_stimer0_handler();
87 add_interrupt_randomness(HYPERV_STIMER0_VECTOR);
88 ack_APIC_irq();
89
90 set_irq_regs(old_regs);
91 }
92
hv_setup_stimer0_irq(int * irq,int * vector,void (* handler)(void))93 int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void))
94 {
95 *vector = HYPERV_STIMER0_VECTOR;
96 *irq = -1; /* Unused on x86/x64 */
97 hv_stimer0_handler = handler;
98 return 0;
99 }
100 EXPORT_SYMBOL_GPL(hv_setup_stimer0_irq);
101
hv_remove_stimer0_irq(int irq)102 void hv_remove_stimer0_irq(int irq)
103 {
104 /* We have no way to deallocate the interrupt gate */
105 hv_stimer0_handler = NULL;
106 }
107 EXPORT_SYMBOL_GPL(hv_remove_stimer0_irq);
108
hv_setup_kexec_handler(void (* handler)(void))109 void hv_setup_kexec_handler(void (*handler)(void))
110 {
111 hv_kexec_handler = handler;
112 }
113 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
114
hv_remove_kexec_handler(void)115 void hv_remove_kexec_handler(void)
116 {
117 hv_kexec_handler = NULL;
118 }
119 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
120
hv_setup_crash_handler(void (* handler)(struct pt_regs * regs))121 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
122 {
123 hv_crash_handler = handler;
124 }
125 EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
126
hv_remove_crash_handler(void)127 void hv_remove_crash_handler(void)
128 {
129 hv_crash_handler = NULL;
130 }
131 EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
132
133 #ifdef CONFIG_KEXEC_CORE
hv_machine_shutdown(void)134 static void hv_machine_shutdown(void)
135 {
136 if (kexec_in_progress && hv_kexec_handler)
137 hv_kexec_handler();
138
139 /*
140 * Call hv_cpu_die() on all the CPUs, otherwise later the hypervisor
141 * corrupts the old VP Assist Pages and can crash the kexec kernel.
142 */
143 if (kexec_in_progress && hyperv_init_cpuhp > 0)
144 cpuhp_remove_state(hyperv_init_cpuhp);
145
146 /* The function calls stop_other_cpus(). */
147 native_machine_shutdown();
148
149 /* Disable the hypercall page when there is only 1 active CPU. */
150 if (kexec_in_progress)
151 hyperv_cleanup();
152 }
153
hv_machine_crash_shutdown(struct pt_regs * regs)154 static void hv_machine_crash_shutdown(struct pt_regs *regs)
155 {
156 if (hv_crash_handler)
157 hv_crash_handler(regs);
158
159 /* The function calls crash_smp_send_stop(). */
160 native_machine_crash_shutdown(regs);
161
162 /* Disable the hypercall page when there is only 1 active CPU. */
163 hyperv_cleanup();
164 }
165 #endif /* CONFIG_KEXEC_CORE */
166 #endif /* CONFIG_HYPERV */
167
ms_hyperv_platform(void)168 static uint32_t __init ms_hyperv_platform(void)
169 {
170 u32 eax;
171 u32 hyp_signature[3];
172
173 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
174 return 0;
175
176 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
177 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
178
179 if (eax >= HYPERV_CPUID_MIN &&
180 eax <= HYPERV_CPUID_MAX &&
181 !memcmp("Microsoft Hv", hyp_signature, 12))
182 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
183
184 return 0;
185 }
186
hv_get_nmi_reason(void)187 static unsigned char hv_get_nmi_reason(void)
188 {
189 return 0;
190 }
191
192 #ifdef CONFIG_X86_LOCAL_APIC
193 /*
194 * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes
195 * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle
196 * unknown NMI on the first CPU which gets it.
197 */
hv_nmi_unknown(unsigned int val,struct pt_regs * regs)198 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs)
199 {
200 static atomic_t nmi_cpu = ATOMIC_INIT(-1);
201
202 if (!unknown_nmi_panic)
203 return NMI_DONE;
204
205 if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1)
206 return NMI_HANDLED;
207
208 return NMI_DONE;
209 }
210 #endif
211
hv_get_tsc_khz(void)212 static unsigned long hv_get_tsc_khz(void)
213 {
214 unsigned long freq;
215
216 rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
217
218 return freq / 1000;
219 }
220
221 #if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV)
hv_smp_prepare_boot_cpu(void)222 static void __init hv_smp_prepare_boot_cpu(void)
223 {
224 native_smp_prepare_boot_cpu();
225 #if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS)
226 hv_init_spinlocks();
227 #endif
228 }
229 #endif
230
ms_hyperv_init_platform(void)231 static void __init ms_hyperv_init_platform(void)
232 {
233 int hv_host_info_eax;
234 int hv_host_info_ebx;
235 int hv_host_info_ecx;
236 int hv_host_info_edx;
237
238 #ifdef CONFIG_PARAVIRT
239 pv_info.name = "Hyper-V";
240 #endif
241
242 /*
243 * Extract the features and hints
244 */
245 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
246 ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
247 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
248
249 pr_info("Hyper-V: features 0x%x, hints 0x%x, misc 0x%x\n",
250 ms_hyperv.features, ms_hyperv.hints, ms_hyperv.misc_features);
251
252 ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS);
253 ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS);
254
255 pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n",
256 ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);
257
258 /*
259 * Extract host information.
260 */
261 if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >=
262 HYPERV_CPUID_VERSION) {
263 hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION);
264 hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION);
265 hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION);
266 hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION);
267
268 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n",
269 hv_host_info_eax, hv_host_info_ebx >> 16,
270 hv_host_info_ebx & 0xFFFF, hv_host_info_ecx,
271 hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF);
272 }
273
274 if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
275 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
276 x86_platform.calibrate_tsc = hv_get_tsc_khz;
277 x86_platform.calibrate_cpu = hv_get_tsc_khz;
278 }
279
280 if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) {
281 ms_hyperv.nested_features =
282 cpuid_eax(HYPERV_CPUID_NESTED_FEATURES);
283 }
284
285 /*
286 * Hyper-V expects to get crash register data or kmsg when
287 * crash enlightment is available and system crashes. Set
288 * crash_kexec_post_notifiers to be true to make sure that
289 * calling crash enlightment interface before running kdump
290 * kernel.
291 */
292 if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE)
293 crash_kexec_post_notifiers = true;
294
295 #ifdef CONFIG_X86_LOCAL_APIC
296 if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
297 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
298 /*
299 * Get the APIC frequency.
300 */
301 u64 hv_lapic_frequency;
302
303 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
304 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
305 lapic_timer_period = hv_lapic_frequency;
306 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n",
307 lapic_timer_period);
308 }
309
310 register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST,
311 "hv_nmi_unknown");
312 #endif
313
314 #ifdef CONFIG_X86_IO_APIC
315 no_timer_check = 1;
316 #endif
317
318 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE)
319 machine_ops.shutdown = hv_machine_shutdown;
320 machine_ops.crash_shutdown = hv_machine_crash_shutdown;
321 #endif
322 if (ms_hyperv.features & HV_ACCESS_TSC_INVARIANT) {
323 wrmsrl(HV_X64_MSR_TSC_INVARIANT_CONTROL, 0x1);
324 setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
325 }
326
327 /*
328 * Generation 2 instances don't support reading the NMI status from
329 * 0x61 port.
330 */
331 if (efi_enabled(EFI_BOOT))
332 x86_platform.get_nmi_reason = hv_get_nmi_reason;
333
334 /*
335 * Hyper-V VMs have a PIT emulation quirk such that zeroing the
336 * counter register during PIT shutdown restarts the PIT. So it
337 * continues to interrupt @18.2 HZ. Setting i8253_clear_counter
338 * to false tells pit_shutdown() not to zero the counter so that
339 * the PIT really is shutdown. Generation 2 VMs don't have a PIT,
340 * and setting this value has no effect.
341 */
342 i8253_clear_counter_on_shutdown = false;
343
344 #if IS_ENABLED(CONFIG_HYPERV)
345 /*
346 * Setup the hook to get control post apic initialization.
347 */
348 x86_platform.apic_post_init = hyperv_init;
349 hyperv_setup_mmu_ops();
350 /* Setup the IDT for hypervisor callback */
351 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_hyperv_callback);
352
353 /* Setup the IDT for reenlightenment notifications */
354 if (ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT) {
355 alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR,
356 asm_sysvec_hyperv_reenlightenment);
357 }
358
359 /* Setup the IDT for stimer0 */
360 if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) {
361 alloc_intr_gate(HYPERV_STIMER0_VECTOR,
362 asm_sysvec_hyperv_stimer0);
363 }
364
365 # ifdef CONFIG_SMP
366 smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu;
367 # endif
368
369 /*
370 * Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic,
371 * set x2apic destination mode to physcial mode when x2apic is available
372 * and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs
373 * have 8-bit APIC id.
374 */
375 # ifdef CONFIG_X86_X2APIC
376 if (x2apic_supported())
377 x2apic_phys = 1;
378 # endif
379
380 /* Register Hyper-V specific clocksource */
381 hv_init_clocksource();
382 #endif
383 /*
384 * TSC should be marked as unstable only after Hyper-V
385 * clocksource has been initialized. This ensures that the
386 * stability of the sched_clock is not altered.
387 */
388 if (!(ms_hyperv.features & HV_ACCESS_TSC_INVARIANT))
389 mark_tsc_unstable("running on Hyper-V");
390 }
391
392 const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
393 .name = "Microsoft Hyper-V",
394 .detect = ms_hyperv_platform,
395 .type = X86_HYPER_MS_HYPERV,
396 .init.init_platform = ms_hyperv_init_platform,
397 };
398