summaryrefslogtreecommitdiff
path: root/arch/x86/kernel/cpu/mshyperv.c
blob: 04cb8d34ccb803ae4a788b4d313c522e23118380 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
/*
 * HyperV  Detection code.
 *
 * Copyright (C) 2010, Novell, Inc.
 * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 */

#include <linux/types.h>
#include <linux/time.h>
#include <linux/clocksource.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/hardirq.h>
#include <linux/efi.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kexec.h>
#include <asm/processor.h>
#include <asm/hypervisor.h>
#include <asm/hyperv.h>
#include <asm/mshyperv.h>
#include <asm/desc.h>
#include <asm/irq_regs.h>
#include <asm/i8259.h>
#include <asm/apic.h>
#include <asm/timer.h>
#include <asm/reboot.h>
#include <asm/nmi.h>

struct ms_hyperv_info ms_hyperv;
EXPORT_SYMBOL_GPL(ms_hyperv);

#if IS_ENABLED(CONFIG_HYPERV)
static void (*vmbus_handler)(void);
static void (*hv_kexec_handler)(void);
static void (*hv_crash_handler)(struct pt_regs *regs);

void hyperv_vector_handler(struct pt_regs *regs)
{
	struct pt_regs *old_regs = set_irq_regs(regs);

	entering_irq();
	inc_irq_stat(irq_hv_callback_count);
	if (vmbus_handler)
		vmbus_handler();

	if (ms_hyperv.hints & HV_X64_DEPRECATING_AEOI_RECOMMENDED)
		ack_APIC_irq();

	exiting_irq();
	set_irq_regs(old_regs);
}

void hv_setup_vmbus_irq(void (*handler)(void))
{
	vmbus_handler = handler;
	/*
	 * Setup the IDT for hypervisor callback. Prevent reallocation
	 * at module reload.
	 */
	if (!test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors))
		alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
				hyperv_callback_vector);
}

void hv_remove_vmbus_irq(void)
{
	/* We have no way to deallocate the interrupt gate */
	vmbus_handler = NULL;
}
EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq);
EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);

void hv_setup_kexec_handler(void (*handler)(void))
{
	hv_kexec_handler = handler;
}
EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);

void hv_remove_kexec_handler(void)
{
	hv_kexec_handler = NULL;
}
EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);

void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
{
	hv_crash_handler = handler;
}
EXPORT_SYMBOL_GPL(hv_setup_crash_handler);

void hv_remove_crash_handler(void)
{
	hv_crash_handler = NULL;
}
EXPORT_SYMBOL_GPL(hv_remove_crash_handler);

#ifdef CONFIG_KEXEC_CORE
static void hv_machine_shutdown(void)
{
	if (kexec_in_progress && hv_kexec_handler)
		hv_kexec_handler();
	native_machine_shutdown();
}

static void hv_machine_crash_shutdown(struct pt_regs *regs)
{
	if (hv_crash_handler)
		hv_crash_handler(regs);
	native_machine_crash_shutdown(regs);
}
#endif /* CONFIG_KEXEC_CORE */
#endif /* CONFIG_HYPERV */

static uint32_t  __init ms_hyperv_platform(void)
{
	u32 eax;
	u32 hyp_signature[3];

	if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
		return 0;

	cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
	      &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);

	if (eax >= HYPERV_CPUID_MIN &&
	    eax <= HYPERV_CPUID_MAX &&
	    !memcmp("Microsoft Hv", hyp_signature, 12))
		return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;

	return 0;
}

static unsigned char hv_get_nmi_reason(void)
{
	return 0;
}

#ifdef CONFIG_X86_LOCAL_APIC
/*
 * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes
 * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle
 * unknown NMI on the first CPU which gets it.
 */
static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs)
{
	static atomic_t nmi_cpu = ATOMIC_INIT(-1);

	if (!unknown_nmi_panic)
		return NMI_DONE;

	if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1)
		return NMI_HANDLED;

	return NMI_DONE;
}
#endif

static void __init ms_hyperv_init_platform(void)
{
	int hv_host_info_eax;
	int hv_host_info_ebx;
	int hv_host_info_ecx;
	int hv_host_info_edx;

	/*
	 * Extract the features and hints
	 */
	ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
	ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
	ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);

	pr_info("HyperV: features 0x%x, hints 0x%x\n",
		ms_hyperv.features, ms_hyperv.hints);

	/*
	 * Extract host information.
	 */
	if (cpuid_eax(HVCPUID_VENDOR_MAXFUNCTION) >= HVCPUID_VERSION) {
		hv_host_info_eax = cpuid_eax(HVCPUID_VERSION);
		hv_host_info_ebx = cpuid_ebx(HVCPUID_VERSION);
		hv_host_info_ecx = cpuid_ecx(HVCPUID_VERSION);
		hv_host_info_edx = cpuid_edx(HVCPUID_VERSION);

		pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n",
			hv_host_info_eax, hv_host_info_ebx >> 16,
			hv_host_info_ebx & 0xFFFF, hv_host_info_ecx,
			hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF);
	}

#ifdef CONFIG_X86_LOCAL_APIC
	if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) {
		/*
		 * Get the APIC frequency.
		 */
		u64	hv_lapic_frequency;

		rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
		hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
		lapic_timer_frequency = hv_lapic_frequency;
		pr_info("HyperV: LAPIC Timer Frequency: %#x\n",
			lapic_timer_frequency);
	}

	register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST,
			     "hv_nmi_unknown");
#endif

#ifdef CONFIG_X86_IO_APIC
	no_timer_check = 1;
#endif

#if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE)
	machine_ops.shutdown = hv_machine_shutdown;
	machine_ops.crash_shutdown = hv_machine_crash_shutdown;
#endif
	mark_tsc_unstable("running on Hyper-V");

	/*
	 * Generation 2 instances don't support reading the NMI status from
	 * 0x61 port.
	 */
	if (efi_enabled(EFI_BOOT))
		x86_platform.get_nmi_reason = hv_get_nmi_reason;

#if IS_ENABLED(CONFIG_HYPERV)
	/*
	 * Setup the hook to get control post apic initialization.
	 */
	x86_platform.apic_post_init = hyperv_init;
#endif
}

const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
	.name			= "Microsoft HyperV",
	.detect			= ms_hyperv_platform,
	.init_platform		= ms_hyperv_init_platform,
};
EXPORT_SYMBOL(x86_hyper_ms_hyperv);