v4.19.13 snapshot.
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
new file mode 100644
index 0000000..852e74e
--- /dev/null
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -0,0 +1,325 @@
+/*
+ * 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 <linux/i8253.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>
+
+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();
+ 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 = 0; /* 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;
+}
+
+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_frequency = hv_lapic_frequency;
+ pr_info("Hyper-V: 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;
+
+ /*
+ * 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);
+#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,
+};