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, 0);
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 native_machine_shutdown();
139 }
140
hv_machine_crash_shutdown(struct pt_regs * regs)141 static void hv_machine_crash_shutdown(struct pt_regs *regs)
142 {
143 if (hv_crash_handler)
144 hv_crash_handler(regs);
145 native_machine_crash_shutdown(regs);
146 }
147 #endif /* CONFIG_KEXEC_CORE */
148 #endif /* CONFIG_HYPERV */
149
ms_hyperv_platform(void)150 static uint32_t __init ms_hyperv_platform(void)
151 {
152 u32 eax;
153 u32 hyp_signature[3];
154
155 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
156 return 0;
157
158 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
159 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
160
161 if (eax >= HYPERV_CPUID_MIN &&
162 eax <= HYPERV_CPUID_MAX &&
163 !memcmp("Microsoft Hv", hyp_signature, 12))
164 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
165
166 return 0;
167 }
168
hv_get_nmi_reason(void)169 static unsigned char hv_get_nmi_reason(void)
170 {
171 return 0;
172 }
173
174 #ifdef CONFIG_X86_LOCAL_APIC
175 /*
176 * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes
177 * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle
178 * unknown NMI on the first CPU which gets it.
179 */
hv_nmi_unknown(unsigned int val,struct pt_regs * regs)180 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs)
181 {
182 static atomic_t nmi_cpu = ATOMIC_INIT(-1);
183
184 if (!unknown_nmi_panic)
185 return NMI_DONE;
186
187 if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1)
188 return NMI_HANDLED;
189
190 return NMI_DONE;
191 }
192 #endif
193
hv_get_tsc_khz(void)194 static unsigned long hv_get_tsc_khz(void)
195 {
196 unsigned long freq;
197
198 rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
199
200 return freq / 1000;
201 }
202
203 #if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV)
hv_smp_prepare_boot_cpu(void)204 static void __init hv_smp_prepare_boot_cpu(void)
205 {
206 native_smp_prepare_boot_cpu();
207 #if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS)
208 hv_init_spinlocks();
209 #endif
210 }
211 #endif
212
ms_hyperv_init_platform(void)213 static void __init ms_hyperv_init_platform(void)
214 {
215 int hv_host_info_eax;
216 int hv_host_info_ebx;
217 int hv_host_info_ecx;
218 int hv_host_info_edx;
219
220 #ifdef CONFIG_PARAVIRT
221 pv_info.name = "Hyper-V";
222 #endif
223
224 /*
225 * Extract the features and hints
226 */
227 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
228 ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
229 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
230
231 pr_info("Hyper-V: features 0x%x, hints 0x%x, misc 0x%x\n",
232 ms_hyperv.features, ms_hyperv.hints, ms_hyperv.misc_features);
233
234 ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS);
235 ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS);
236
237 pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n",
238 ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);
239
240 /*
241 * Extract host information.
242 */
243 if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >=
244 HYPERV_CPUID_VERSION) {
245 hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION);
246 hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION);
247 hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION);
248 hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION);
249
250 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n",
251 hv_host_info_eax, hv_host_info_ebx >> 16,
252 hv_host_info_ebx & 0xFFFF, hv_host_info_ecx,
253 hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF);
254 }
255
256 if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
257 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
258 x86_platform.calibrate_tsc = hv_get_tsc_khz;
259 x86_platform.calibrate_cpu = hv_get_tsc_khz;
260 }
261
262 if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) {
263 ms_hyperv.nested_features =
264 cpuid_eax(HYPERV_CPUID_NESTED_FEATURES);
265 }
266
267 /*
268 * Hyper-V expects to get crash register data or kmsg when
269 * crash enlightment is available and system crashes. Set
270 * crash_kexec_post_notifiers to be true to make sure that
271 * calling crash enlightment interface before running kdump
272 * kernel.
273 */
274 if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE)
275 crash_kexec_post_notifiers = true;
276
277 #ifdef CONFIG_X86_LOCAL_APIC
278 if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
279 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
280 /*
281 * Get the APIC frequency.
282 */
283 u64 hv_lapic_frequency;
284
285 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
286 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
287 lapic_timer_period = hv_lapic_frequency;
288 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n",
289 lapic_timer_period);
290 }
291
292 register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST,
293 "hv_nmi_unknown");
294 #endif
295
296 #ifdef CONFIG_X86_IO_APIC
297 no_timer_check = 1;
298 #endif
299
300 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE)
301 machine_ops.shutdown = hv_machine_shutdown;
302 machine_ops.crash_shutdown = hv_machine_crash_shutdown;
303 #endif
304 if (ms_hyperv.features & HV_ACCESS_TSC_INVARIANT) {
305 wrmsrl(HV_X64_MSR_TSC_INVARIANT_CONTROL, 0x1);
306 setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
307 } else {
308 mark_tsc_unstable("running on Hyper-V");
309 }
310
311 /*
312 * Generation 2 instances don't support reading the NMI status from
313 * 0x61 port.
314 */
315 if (efi_enabled(EFI_BOOT))
316 x86_platform.get_nmi_reason = hv_get_nmi_reason;
317
318 /*
319 * Hyper-V VMs have a PIT emulation quirk such that zeroing the
320 * counter register during PIT shutdown restarts the PIT. So it
321 * continues to interrupt @18.2 HZ. Setting i8253_clear_counter
322 * to false tells pit_shutdown() not to zero the counter so that
323 * the PIT really is shutdown. Generation 2 VMs don't have a PIT,
324 * and setting this value has no effect.
325 */
326 i8253_clear_counter_on_shutdown = false;
327
328 #if IS_ENABLED(CONFIG_HYPERV)
329 /*
330 * Setup the hook to get control post apic initialization.
331 */
332 x86_platform.apic_post_init = hyperv_init;
333 hyperv_setup_mmu_ops();
334 /* Setup the IDT for hypervisor callback */
335 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_hyperv_callback);
336
337 /* Setup the IDT for reenlightenment notifications */
338 if (ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT) {
339 alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR,
340 asm_sysvec_hyperv_reenlightenment);
341 }
342
343 /* Setup the IDT for stimer0 */
344 if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) {
345 alloc_intr_gate(HYPERV_STIMER0_VECTOR,
346 asm_sysvec_hyperv_stimer0);
347 }
348
349 # ifdef CONFIG_SMP
350 smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu;
351 # endif
352
353 /*
354 * Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic,
355 * set x2apic destination mode to physcial mode when x2apic is available
356 * and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs
357 * have 8-bit APIC id.
358 */
359 # ifdef CONFIG_X86_X2APIC
360 if (x2apic_supported())
361 x2apic_phys = 1;
362 # endif
363
364 /* Register Hyper-V specific clocksource */
365 hv_init_clocksource();
366 #endif
367 }
368
369 const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
370 .name = "Microsoft Hyper-V",
371 .detect = ms_hyperv_platform,
372 .type = X86_HYPER_MS_HYPERV,
373 .init.init_platform = ms_hyperv_init_platform,
374 };
375
