1 files changed, 516 insertions, 0 deletions
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
new file mode 100644
index 000000000..38c31e164
--- /dev/null
+++ b/arch/x86/hyperv/hv_init.c
@@ -0,0 +1,516 @@
+/*
+ * X86 specific Hyper-V initialization code.
+ *
+ * Copyright (C) 2016, Microsoft, Inc.
+ *
+ * Author : K. Y. Srinivasan <kys@microsoft.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ *
+ */
+
+#include <linux/efi.h>
+#include <linux/types.h>
+#include <asm/apic.h>
+#include <asm/desc.h>
+#include <asm/hypervisor.h>
+#include <asm/hyperv-tlfs.h>
+#include <asm/mshyperv.h>
+#include <linux/version.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+#include <linux/clockchips.h>
+#include <linux/hyperv.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/cpuhotplug.h>
+
+#ifdef CONFIG_HYPERV_TSCPAGE
+
+static struct ms_hyperv_tsc_page *tsc_pg;
+
+struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
+{
+	return tsc_pg;
+}
+EXPORT_SYMBOL_GPL(hv_get_tsc_page);
+
+static u64 read_hv_clock_tsc(struct clocksource *arg)
+{
+	u64 current_tick = hv_read_tsc_page(tsc_pg);
+
+	if (current_tick == U64_MAX)
+		rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
+
+	return current_tick;
+}
+
+static struct clocksource hyperv_cs_tsc = {
+		.name		= "hyperv_clocksource_tsc_page",
+		.rating		= 400,
+		.read		= read_hv_clock_tsc,
+		.mask		= CLOCKSOURCE_MASK(64),
+		.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+#endif
+
+static u64 read_hv_clock_msr(struct clocksource *arg)
+{
+	u64 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_msr = {
+	.name		= "hyperv_clocksource_msr",
+	.rating		= 400,
+	.read		= read_hv_clock_msr,
+	.mask		= CLOCKSOURCE_MASK(64),
+	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+void *hv_hypercall_pg;
+EXPORT_SYMBOL_GPL(hv_hypercall_pg);
+struct clocksource *hyperv_cs;
+EXPORT_SYMBOL_GPL(hyperv_cs);
+
+u32 *hv_vp_index;
+EXPORT_SYMBOL_GPL(hv_vp_index);
+
+struct hv_vp_assist_page **hv_vp_assist_page;
+EXPORT_SYMBOL_GPL(hv_vp_assist_page);
+
+void  __percpu **hyperv_pcpu_input_arg;
+EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
+
+u32 hv_max_vp_index;
+
+static int hv_cpu_init(unsigned int cpu)
+{
+	u64 msr_vp_index;
+	struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
+	void **input_arg;
+	struct page *pg;
+
+	input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
+	pg = alloc_page(GFP_KERNEL);
+	if (unlikely(!pg))
+		return -ENOMEM;
+	*input_arg = page_address(pg);
+
+	hv_get_vp_index(msr_vp_index);
+
+	hv_vp_index[smp_processor_id()] = msr_vp_index;
+
+	if (msr_vp_index > hv_max_vp_index)
+		hv_max_vp_index = msr_vp_index;
+
+	if (!hv_vp_assist_page)
+		return 0;
+
+	if (!*hvp)
+		*hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
+
+	if (*hvp) {
+		u64 val;
+
+		val = vmalloc_to_pfn(*hvp);
+		val = (val << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT) |
+			HV_X64_MSR_VP_ASSIST_PAGE_ENABLE;
+
+		wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, val);
+	}
+
+	return 0;
+}
+
+static void (*hv_reenlightenment_cb)(void);
+
+static void hv_reenlightenment_notify(struct work_struct *dummy)
+{
+	struct hv_tsc_emulation_status emu_status;
+
+	rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
+
+	/* Don't issue the callback if TSC accesses are not emulated */
+	if (hv_reenlightenment_cb && emu_status.inprogress)
+		hv_reenlightenment_cb();
+}
+static DECLARE_DELAYED_WORK(hv_reenlightenment_work, hv_reenlightenment_notify);
+
+void hyperv_stop_tsc_emulation(void)
+{
+	u64 freq;
+	struct hv_tsc_emulation_status emu_status;
+
+	rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
+	emu_status.inprogress = 0;
+	wrmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
+
+	rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
+	tsc_khz = div64_u64(freq, 1000);
+}
+EXPORT_SYMBOL_GPL(hyperv_stop_tsc_emulation);
+
+static inline bool hv_reenlightenment_available(void)
+{
+	/*
+	 * Check for required features and priviliges to make TSC frequency
+	 * change notifications work.
+	 */
+	return ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
+		ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE &&
+		ms_hyperv.features & HV_X64_ACCESS_REENLIGHTENMENT;
+}
+
+__visible void __irq_entry hyperv_reenlightenment_intr(struct pt_regs *regs)
+{
+	entering_ack_irq();
+
+	inc_irq_stat(irq_hv_reenlightenment_count);
+
+	schedule_delayed_work(&hv_reenlightenment_work, HZ/10);
+
+	exiting_irq();
+}
+
+void set_hv_tscchange_cb(void (*cb)(void))
+{
+	struct hv_reenlightenment_control re_ctrl = {
+		.vector = HYPERV_REENLIGHTENMENT_VECTOR,
+		.enabled = 1,
+	};
+	struct hv_tsc_emulation_control emu_ctrl = {.enabled = 1};
+
+	if (!hv_reenlightenment_available()) {
+		pr_warn("Hyper-V: reenlightenment support is unavailable\n");
+		return;
+	}
+
+	if (!hv_vp_index)
+		return;
+
+	hv_reenlightenment_cb = cb;
+
+	/* Make sure callback is registered before we write to MSRs */
+	wmb();
+
+	re_ctrl.target_vp = hv_vp_index[get_cpu()];
+
+	wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
+	wrmsrl(HV_X64_MSR_TSC_EMULATION_CONTROL, *((u64 *)&emu_ctrl));
+
+	put_cpu();
+}
+EXPORT_SYMBOL_GPL(set_hv_tscchange_cb);
+
+void clear_hv_tscchange_cb(void)
+{
+	struct hv_reenlightenment_control re_ctrl;
+
+	if (!hv_reenlightenment_available())
+		return;
+
+	rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
+	re_ctrl.enabled = 0;
+	wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
+
+	hv_reenlightenment_cb = NULL;
+}
+EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb);
+
+static int hv_cpu_die(unsigned int cpu)
+{
+	struct hv_reenlightenment_control re_ctrl;
+	unsigned int new_cpu;
+	unsigned long flags;
+	void **input_arg;
+	void *input_pg = NULL;
+
+	local_irq_save(flags);
+	input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
+	input_pg = *input_arg;
+	*input_arg = NULL;
+	local_irq_restore(flags);
+	free_page((unsigned long)input_pg);
+
+	if (hv_vp_assist_page && hv_vp_assist_page[cpu])
+		wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0);
+
+	if (hv_reenlightenment_cb == NULL)
+		return 0;
+
+	rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
+	if (re_ctrl.target_vp == hv_vp_index[cpu]) {
+		/* Reassign to some other online CPU */
+		new_cpu = cpumask_any_but(cpu_online_mask, cpu);
+
+		re_ctrl.target_vp = hv_vp_index[new_cpu];
+		wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
+	}
+
+	return 0;
+}
+
+static int __init hv_pci_init(void)
+{
+	int gen2vm = efi_enabled(EFI_BOOT);
+
+	/*
+	 * For Generation-2 VM, we exit from pci_arch_init() by returning 0.
+	 * The purpose is to suppress the harmless warning:
+	 * "PCI: Fatal: No config space access function found"
+	 */
+	if (gen2vm)
+		return 0;
+
+	/* For Generation-1 VM, we'll proceed in pci_arch_init().  */
+	return 1;
+}
+
+/*
+ * This function is to be invoked early in the boot sequence after the
+ * hypervisor has been detected.
+ *
+ * 1. Setup the hypercall page.
+ * 2. Register Hyper-V specific clocksource.
+ * 3. Setup Hyper-V specific APIC entry points.
+ */
+void __init hyperv_init(void)
+{
+	u64 guest_id, required_msrs;
+	union hv_x64_msr_hypercall_contents hypercall_msr;
+	int cpuhp, i;
+
+	if (x86_hyper_type != X86_HYPER_MS_HYPERV)
+		return;
+
+	/* Absolutely required MSRs */
+	required_msrs = HV_X64_MSR_HYPERCALL_AVAILABLE |
+		HV_X64_MSR_VP_INDEX_AVAILABLE;
+
+	if ((ms_hyperv.features & required_msrs) != required_msrs)
+		return;
+
+	/*
+	 * Allocate the per-CPU state for the hypercall input arg.
+	 * If this allocation fails, we will not be able to setup
+	 * (per-CPU) hypercall input page and thus this failure is
+	 * fatal on Hyper-V.
+	 */
+	hyperv_pcpu_input_arg = alloc_percpu(void  *);
+
+	BUG_ON(hyperv_pcpu_input_arg == NULL);
+
+	/* Allocate percpu VP index */
+	hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
+				    GFP_KERNEL);
+	if (!hv_vp_index)
+		return;
+
+	for (i = 0; i < num_possible_cpus(); i++)
+		hv_vp_index[i] = VP_INVAL;
+
+	hv_vp_assist_page = kcalloc(num_possible_cpus(),
+				    sizeof(*hv_vp_assist_page), GFP_KERNEL);
+	if (!hv_vp_assist_page) {
+		ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
+		goto free_vp_index;
+	}
+
+	cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
+				  hv_cpu_init, hv_cpu_die);
+	if (cpuhp < 0)
+		goto free_vp_assist_page;
+
+	/*
+	 * Setup the hypercall page and enable hypercalls.
+	 * 1. Register the guest ID
+	 * 2. Enable the hypercall and register the hypercall page
+	 */
+	guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
+	wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
+
+	hv_hypercall_pg  = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
+	if (hv_hypercall_pg == NULL) {
+		wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
+		goto remove_cpuhp_state;
+	}
+
+	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+	hypercall_msr.enable = 1;
+	hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
+	wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+
+	hv_apic_init();
+
+	x86_init.pci.arch_init = hv_pci_init;
+
+	/*
+	 * Register Hyper-V specific clocksource.
+	 */
+#ifdef CONFIG_HYPERV_TSCPAGE
+	if (ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE) {
+		union hv_x64_msr_hypercall_contents tsc_msr;
+
+		tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
+		if (!tsc_pg)
+			goto register_msr_cs;
+
+		hyperv_cs = &hyperv_cs_tsc;
+
+		rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
+
+		tsc_msr.enable = 1;
+		tsc_msr.guest_physical_address = vmalloc_to_pfn(tsc_pg);
+
+		wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
+
+		hyperv_cs_tsc.archdata.vclock_mode = VCLOCK_HVCLOCK;
+
+		clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
+		return;
+	}
+register_msr_cs:
+#endif
+	/*
+	 * For 32 bit guests just use the MSR based mechanism for reading
+	 * the partition counter.
+	 */
+
+	hyperv_cs = &hyperv_cs_msr;
+	if (ms_hyperv.features & HV_MSR_TIME_REF_COUNT_AVAILABLE)
+		clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
+
+	return;
+
+remove_cpuhp_state:
+	cpuhp_remove_state(cpuhp);
+free_vp_assist_page:
+	kfree(hv_vp_assist_page);
+	hv_vp_assist_page = NULL;
+free_vp_index:
+	kfree(hv_vp_index);
+	hv_vp_index = NULL;
+}
+
+/*
+ * This routine is called before kexec/kdump, it does the required cleanup.
+ */
+void hyperv_cleanup(void)
+{
+	union hv_x64_msr_hypercall_contents hypercall_msr;
+
+	/* Reset our OS id */
+	wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
+
+	/*
+	 * Reset hypercall page reference before reset the page,
+	 * let hypercall operations fail safely rather than
+	 * panic the kernel for using invalid hypercall page
+	 */
+	hv_hypercall_pg = NULL;
+
+	/* Reset the hypercall page */
+	hypercall_msr.as_uint64 = 0;
+	wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+
+	/* Reset the TSC page */
+	hypercall_msr.as_uint64 = 0;
+	wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
+}
+EXPORT_SYMBOL_GPL(hyperv_cleanup);
+
+void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die)
+{
+	static bool panic_reported;
+	u64 guest_id;
+
+	if (in_die && !panic_on_oops)
+		return;
+
+	/*
+	 * We prefer to report panic on 'die' chain as we have proper
+	 * registers to report, but if we miss it (e.g. on BUG()) we need
+	 * to report it on 'panic'.
+	 */
+	if (panic_reported)
+		return;
+	panic_reported = true;
+
+	rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
+
+	wrmsrl(HV_X64_MSR_CRASH_P0, err);
+	wrmsrl(HV_X64_MSR_CRASH_P1, guest_id);
+	wrmsrl(HV_X64_MSR_CRASH_P2, regs->ip);
+	wrmsrl(HV_X64_MSR_CRASH_P3, regs->ax);
+	wrmsrl(HV_X64_MSR_CRASH_P4, regs->sp);
+
+	/*
+	 * Let Hyper-V know there is crash data available
+	 */
+	wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
+}
+EXPORT_SYMBOL_GPL(hyperv_report_panic);
+
+/**
+ * hyperv_report_panic_msg - report panic message to Hyper-V
+ * @pa: physical address of the panic page containing the message
+ * @size: size of the message in the page
+ */
+void hyperv_report_panic_msg(phys_addr_t pa, size_t size)
+{
+	/*
+	 * P3 to contain the physical address of the panic page & P4 to
+	 * contain the size of the panic data in that page. Rest of the
+	 * registers are no-op when the NOTIFY_MSG flag is set.
+	 */
+	wrmsrl(HV_X64_MSR_CRASH_P0, 0);
+	wrmsrl(HV_X64_MSR_CRASH_P1, 0);
+	wrmsrl(HV_X64_MSR_CRASH_P2, 0);
+	wrmsrl(HV_X64_MSR_CRASH_P3, pa);
+	wrmsrl(HV_X64_MSR_CRASH_P4, size);
+
+	/*
+	 * Let Hyper-V know there is crash data available along with
+	 * the panic message.
+	 */
+	wrmsrl(HV_X64_MSR_CRASH_CTL,
+	       (HV_CRASH_CTL_CRASH_NOTIFY | HV_CRASH_CTL_CRASH_NOTIFY_MSG));
+}
+EXPORT_SYMBOL_GPL(hyperv_report_panic_msg);
+
+bool hv_is_hyperv_initialized(void)
+{
+	union hv_x64_msr_hypercall_contents hypercall_msr;
+
+	/*
+	 * Ensure that we're really on Hyper-V, and not a KVM or Xen
+	 * emulation of Hyper-V
+	 */
+	if (x86_hyper_type != X86_HYPER_MS_HYPERV)
+		return false;
+
+	/*
+	 * Verify that earlier initialization succeeded by checking
+	 * that the hypercall page is setup
+	 */
+	hypercall_msr.as_uint64 = 0;
+	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+
+	return hypercall_msr.enable;
+}
+EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);