linux/arch/x86/kernel/cpu/mshyperv.c

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/*
* 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/module.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/idle.h>
#include <asm/irq_regs.h>
#include <asm/i8259.h>
#include <asm/apic.h>
#include <asm/timer.h>
#include <asm/reboot.h>
struct ms_hyperv_info ms_hyperv;
EXPORT_SYMBOL_GPL(ms_hyperv);
static void (*hv_kexec_handler)(void);
static void (*hv_crash_handler)(struct pt_regs *regs);
#if IS_ENABLED(CONFIG_HYPERV)
static void (*vmbus_handler)(void);
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();
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);
#endif
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);
}
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 cycle_t read_hv_clock(struct clocksource *arg)
{
cycle_t current_tick;
/*
* Read the partition counter to get the current tick count. This count
* is set to 0 when the partition is created and is incremented in
* 100 nanosecond units.
*/
rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
return current_tick;
}
static struct clocksource hyperv_cs = {
.name = "hyperv_clocksource",
.rating = 400, /* use this when running on Hyperv*/
.read = read_hv_clock,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static void __init ms_hyperv_init_platform(void)
{
/*
* 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);
printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",
ms_hyperv.features, ms_hyperv.hints);
#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;
printk(KERN_INFO "HyperV: LAPIC Timer Frequency: %#x\n",
lapic_timer_frequency);
}
#endif
if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
#ifdef CONFIG_X86_IO_APIC
no_timer_check = 1;
#endif
machine_ops.shutdown = hv_machine_shutdown;
machine_ops.crash_shutdown = hv_machine_crash_shutdown;
mark_tsc_unstable("running on Hyper-V");
}
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);