summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/cpu/mshyperv.c
blob: 267daad8c0360890672e7db5369fde36fb58174e (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
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
// SPDX-License-Identifier: GPL-2.0-only
/*
 * HyperV  Detection code.
 *
 * Copyright (C) 2010, Novell, Inc.
 * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
 */

#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 <linux/i8253.h>
#include <linux/random.h>
#include <asm/processor.h>
#include <asm/hypervisor.h>
#include <asm/hyperv-tlfs.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>
#include <clocksource/hyperv_timer.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_stimer0_handler)(void);
static void (*hv_kexec_handler)(void);
static void (*hv_crash_handler)(struct pt_regs *regs);

__visible void __irq_entry 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_DEPRECATING_AEOI_RECOMMENDED)
		ack_APIC_irq();

	exiting_irq();
	set_irq_regs(old_regs);
}

void hv_setup_vmbus_irq(void (*handler)(void))
{
	vmbus_handler = handler;
}

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);

/*
 * Routines to do per-architecture handling of stimer0
 * interrupts when in Direct Mode
 */

__visible void __irq_entry hv_stimer0_vector_handler(struct pt_regs *regs)
{
	struct pt_regs *old_regs = set_irq_regs(regs);

	entering_irq();
	inc_irq_stat(hyperv_stimer0_count);
	if (hv_stimer0_handler)
		hv_stimer0_handler();
	add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0);
	ack_APIC_irq();

	exiting_irq();
	set_irq_regs(old_regs);
}

int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void))
{
	*vector = HYPERV_STIMER0_VECTOR;
	*irq = -1;   /* Unused on x86/x64 */
	hv_stimer0_handler = handler;
	return 0;
}
EXPORT_SYMBOL_GPL(hv_setup_stimer0_irq);

void hv_remove_stimer0_irq(int irq)
{
	/* We have no way to deallocate the interrupt gate */
	hv_stimer0_handler = NULL;
}
EXPORT_SYMBOL_GPL(hv_remove_stimer0_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 unsigned long hv_get_tsc_khz(void)
{
	unsigned long freq;

	rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);

	return freq / 1000;
}

#if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV)
static void __init hv_smp_prepare_boot_cpu(void)
{
	native_smp_prepare_boot_cpu();
#if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS)
	hv_init_spinlocks();
#endif
}
#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("Hyper-V: features 0x%x, hints 0x%x\n",
		ms_hyperv.features, ms_hyperv.hints);

	ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS);
	ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS);

	pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n",
		 ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);

	/*
	 * Extract host information.
	 */
	if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >=
	    HYPERV_CPUID_VERSION) {
		hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION);
		hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION);
		hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION);
		hv_host_info_edx = cpuid_edx(HYPERV_CPUID_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);
	}

	if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
	    ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
		x86_platform.calibrate_tsc = hv_get_tsc_khz;
		x86_platform.calibrate_cpu = hv_get_tsc_khz;
	}

	if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) {
		ms_hyperv.nested_features =
			cpuid_eax(HYPERV_CPUID_NESTED_FEATURES);
	}

#ifdef CONFIG_X86_LOCAL_APIC
	if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
	    ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_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_period = hv_lapic_frequency;
		pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n",
			lapic_timer_period);
	}

	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;

	/*
	 * Hyper-V VMs have a PIT emulation quirk such that zeroing the
	 * counter register during PIT shutdown restarts the PIT. So it
	 * continues to interrupt @18.2 HZ. Setting i8253_clear_counter
	 * to false tells pit_shutdown() not to zero the counter so that
	 * the PIT really is shutdown. Generation 2 VMs don't have a PIT,
	 * and setting this value has no effect.
	 */
	i8253_clear_counter_on_shutdown = false;

#if IS_ENABLED(CONFIG_HYPERV)
	/*
	 * Setup the hook to get control post apic initialization.
	 */
	x86_platform.apic_post_init = hyperv_init;
	hyperv_setup_mmu_ops();
	/* Setup the IDT for hypervisor callback */
	alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);

	/* Setup the IDT for reenlightenment notifications */
	if (ms_hyperv.features & HV_X64_ACCESS_REENLIGHTENMENT)
		alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR,
				hyperv_reenlightenment_vector);

	/* Setup the IDT for stimer0 */
	if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE)
		alloc_intr_gate(HYPERV_STIMER0_VECTOR,
				hv_stimer0_callback_vector);

# ifdef CONFIG_SMP
	smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu;
# endif

	/*
	 * Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic,
	 * set x2apic destination mode to physcial mode when x2apic is available
	 * and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs
	 * have 8-bit APIC id.
	 */
# ifdef CONFIG_X86_X2APIC
	if (x2apic_supported())
		x2apic_phys = 1;
# endif

	/* Register Hyper-V specific clocksource */
	hv_init_clocksource();
#endif
}

void hv_setup_sched_clock(void *sched_clock)
{
#ifdef CONFIG_PARAVIRT
	pv_ops.time.sched_clock = sched_clock;
#endif
}

const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
	.name			= "Microsoft Hyper-V",
	.detect			= ms_hyperv_platform,
	.type			= X86_HYPER_MS_HYPERV,
	.init.init_platform	= ms_hyperv_init_platform,
};