2 * HyperV Detection code.
4 * Copyright (C) 2010, Novell, Inc.
5 * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; version 2 of the License.
13 #include <linux/types.h>
14 #include <linux/time.h>
15 #include <linux/clocksource.h>
16 #include <linux/init.h>
17 #include <linux/export.h>
18 #include <linux/hardirq.h>
19 #include <linux/efi.h>
20 #include <linux/interrupt.h>
21 #include <linux/irq.h>
22 #include <linux/kexec.h>
23 #include <asm/processor.h>
24 #include <asm/hypervisor.h>
25 #include <asm/hyperv.h>
26 #include <asm/mshyperv.h>
29 #include <asm/irq_regs.h>
30 #include <asm/i8259.h>
32 #include <asm/timer.h>
33 #include <asm/reboot.h>
36 struct ms_hyperv_info ms_hyperv;
37 EXPORT_SYMBOL_GPL(ms_hyperv);
39 #if IS_ENABLED(CONFIG_HYPERV)
40 static void (*vmbus_handler)(void);
41 static void (*hv_kexec_handler)(void);
42 static void (*hv_crash_handler)(struct pt_regs *regs);
44 void hyperv_vector_handler(struct pt_regs *regs)
46 struct pt_regs *old_regs = set_irq_regs(regs);
49 inc_irq_stat(irq_hv_callback_count);
54 set_irq_regs(old_regs);
57 void hv_setup_vmbus_irq(void (*handler)(void))
59 vmbus_handler = handler;
61 * Setup the IDT for hypervisor callback. Prevent reallocation
64 if (!test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors))
65 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
66 hyperv_callback_vector);
69 void hv_remove_vmbus_irq(void)
71 /* We have no way to deallocate the interrupt gate */
74 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq);
75 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);
77 void hv_setup_kexec_handler(void (*handler)(void))
79 hv_kexec_handler = handler;
81 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
83 void hv_remove_kexec_handler(void)
85 hv_kexec_handler = NULL;
87 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
89 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
91 hv_crash_handler = handler;
93 EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
95 void hv_remove_crash_handler(void)
97 hv_crash_handler = NULL;
99 EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
101 #ifdef CONFIG_KEXEC_CORE
102 static void hv_machine_shutdown(void)
104 if (kexec_in_progress && hv_kexec_handler)
106 native_machine_shutdown();
109 static void hv_machine_crash_shutdown(struct pt_regs *regs)
111 if (hv_crash_handler)
112 hv_crash_handler(regs);
113 native_machine_crash_shutdown(regs);
115 #endif /* CONFIG_KEXEC_CORE */
116 #endif /* CONFIG_HYPERV */
118 static uint32_t __init ms_hyperv_platform(void)
121 u32 hyp_signature[3];
123 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
126 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
127 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
129 if (eax >= HYPERV_CPUID_MIN &&
130 eax <= HYPERV_CPUID_MAX &&
131 !memcmp("Microsoft Hv", hyp_signature, 12))
132 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
137 static cycle_t read_hv_clock(struct clocksource *arg)
139 cycle_t current_tick;
141 * Read the partition counter to get the current tick count. This count
142 * is set to 0 when the partition is created and is incremented in
143 * 100 nanosecond units.
145 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
149 static struct clocksource hyperv_cs = {
150 .name = "hyperv_clocksource",
151 .rating = 400, /* use this when running on Hyperv*/
152 .read = read_hv_clock,
153 .mask = CLOCKSOURCE_MASK(64),
154 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
157 static unsigned char hv_get_nmi_reason(void)
162 #ifdef CONFIG_X86_LOCAL_APIC
164 * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes
165 * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle
166 * unknown NMI on the first CPU which gets it.
168 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs)
170 static atomic_t nmi_cpu = ATOMIC_INIT(-1);
172 if (!unknown_nmi_panic)
175 if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1)
182 static void __init ms_hyperv_init_platform(void)
185 * Extract the features and hints
187 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
188 ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
189 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
191 pr_info("HyperV: features 0x%x, hints 0x%x\n",
192 ms_hyperv.features, ms_hyperv.hints);
194 #ifdef CONFIG_X86_LOCAL_APIC
195 if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) {
197 * Get the APIC frequency.
199 u64 hv_lapic_frequency;
201 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
202 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
203 lapic_timer_frequency = hv_lapic_frequency;
204 pr_info("HyperV: LAPIC Timer Frequency: %#x\n",
205 lapic_timer_frequency);
208 register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST,
212 if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
213 clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
215 #ifdef CONFIG_X86_IO_APIC
219 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE)
220 machine_ops.shutdown = hv_machine_shutdown;
221 machine_ops.crash_shutdown = hv_machine_crash_shutdown;
223 mark_tsc_unstable("running on Hyper-V");
226 * Generation 2 instances don't support reading the NMI status from
229 if (efi_enabled(EFI_BOOT))
230 x86_platform.get_nmi_reason = hv_get_nmi_reason;
233 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
234 .name = "Microsoft HyperV",
235 .detect = ms_hyperv_platform,
236 .init_platform = ms_hyperv_init_platform,
238 EXPORT_SYMBOL(x86_hyper_ms_hyperv);