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2517281d63
When general-purpose kexec (not kdump) is being performed in Hyper-V guest the newly booted kernel fails with an MCE error coming from the host. It is the same error which was fixed in the "Drivers: hv: vmbus: Implement the protocol for tearing down vmbus state" commit - monitor pages remain special and when they're being written to (as the new kernel doesn't know these pages are special) bad things happen. We need to perform some minimalistic cleanup before booting a new kernel on kexec. To do so we need to register a special machine_ops.shutdown handler to be executed before the native_machine_shutdown(). Registering a shutdown notification handler via the register_reboot_notifier() call is not sufficient as it happens to early for our purposes. machine_ops is not being exported to modules (and I don't think we want to export it) so let's do this in mshyperv.c The minimalistic cleanup consists of cleaning up clockevents, synic MSRs, guest os id MSR, and hypercall MSR. Kdump doesn't require all this stuff as it lives in a separate memory space. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
175 lines
4.2 KiB
C
175 lines
4.2 KiB
C
/*
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* HyperV Detection code.
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*
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* Copyright (C) 2010, Novell, Inc.
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* Author : K. Y. Srinivasan <ksrinivasan@novell.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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*/
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#include <linux/types.h>
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#include <linux/time.h>
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#include <linux/clocksource.h>
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#include <linux/module.h>
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#include <linux/hardirq.h>
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#include <linux/efi.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/kexec.h>
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#include <asm/processor.h>
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#include <asm/hypervisor.h>
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#include <asm/hyperv.h>
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#include <asm/mshyperv.h>
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#include <asm/desc.h>
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#include <asm/idle.h>
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#include <asm/irq_regs.h>
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#include <asm/i8259.h>
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#include <asm/apic.h>
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#include <asm/timer.h>
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#include <asm/reboot.h>
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struct ms_hyperv_info ms_hyperv;
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EXPORT_SYMBOL_GPL(ms_hyperv);
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static void (*hv_kexec_handler)(void);
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#if IS_ENABLED(CONFIG_HYPERV)
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static void (*vmbus_handler)(void);
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void hyperv_vector_handler(struct pt_regs *regs)
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{
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struct pt_regs *old_regs = set_irq_regs(regs);
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entering_irq();
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inc_irq_stat(irq_hv_callback_count);
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if (vmbus_handler)
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vmbus_handler();
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exiting_irq();
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set_irq_regs(old_regs);
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}
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void hv_setup_vmbus_irq(void (*handler)(void))
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{
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vmbus_handler = handler;
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/*
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* Setup the IDT for hypervisor callback. Prevent reallocation
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* at module reload.
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*/
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if (!test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors))
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alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
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hyperv_callback_vector);
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}
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void hv_remove_vmbus_irq(void)
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{
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/* We have no way to deallocate the interrupt gate */
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vmbus_handler = NULL;
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}
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EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq);
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EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);
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void hv_setup_kexec_handler(void (*handler)(void))
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{
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hv_kexec_handler = handler;
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}
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EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
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void hv_remove_kexec_handler(void)
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{
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hv_kexec_handler = NULL;
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}
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EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
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#endif
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static void hv_machine_shutdown(void)
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{
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if (kexec_in_progress && hv_kexec_handler)
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hv_kexec_handler();
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native_machine_shutdown();
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}
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static uint32_t __init ms_hyperv_platform(void)
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{
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u32 eax;
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u32 hyp_signature[3];
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if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
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return 0;
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cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
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&eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
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if (eax >= HYPERV_CPUID_MIN &&
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eax <= HYPERV_CPUID_MAX &&
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!memcmp("Microsoft Hv", hyp_signature, 12))
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return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
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return 0;
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}
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static cycle_t read_hv_clock(struct clocksource *arg)
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{
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cycle_t current_tick;
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/*
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* Read the partition counter to get the current tick count. This count
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* is set to 0 when the partition is created and is incremented in
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* 100 nanosecond units.
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*/
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rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
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return current_tick;
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}
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static struct clocksource hyperv_cs = {
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.name = "hyperv_clocksource",
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.rating = 400, /* use this when running on Hyperv*/
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.read = read_hv_clock,
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.mask = CLOCKSOURCE_MASK(64),
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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};
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static void __init ms_hyperv_init_platform(void)
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{
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/*
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* Extract the features and hints
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*/
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ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
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ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
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printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",
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ms_hyperv.features, ms_hyperv.hints);
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#ifdef CONFIG_X86_LOCAL_APIC
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if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) {
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/*
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* Get the APIC frequency.
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*/
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u64 hv_lapic_frequency;
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rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
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hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
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lapic_timer_frequency = hv_lapic_frequency;
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printk(KERN_INFO "HyperV: LAPIC Timer Frequency: %#x\n",
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lapic_timer_frequency);
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}
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#endif
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if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
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clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
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#ifdef CONFIG_X86_IO_APIC
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no_timer_check = 1;
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#endif
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machine_ops.shutdown = hv_machine_shutdown;
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}
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const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
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.name = "Microsoft HyperV",
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.detect = ms_hyperv_platform,
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.init_platform = ms_hyperv_init_platform,
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};
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EXPORT_SYMBOL(x86_hyper_ms_hyperv);
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