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![Dexuan Cui](/assets/img/avatar_default.png)
For hibernation the hypercall page must be disabled before the hibernation image is created so that subsequent hypercall operations fail safely. On resume the hypercall page has to be restored and reenabled to ensure proper operation of the resumed kernel. Implement the necessary suspend/resume callbacks. [ tglx: Decrypted changelog ] Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/1578350559-130275-1-git-send-email-decui@microsoft.com
504 lines
13 KiB
C
504 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* X86 specific Hyper-V initialization code.
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*
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* Copyright (C) 2016, Microsoft, Inc.
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*
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* Author : K. Y. Srinivasan <kys@microsoft.com>
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*/
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#include <linux/acpi.h>
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#include <linux/efi.h>
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#include <linux/types.h>
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#include <asm/apic.h>
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#include <asm/desc.h>
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#include <asm/hypervisor.h>
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#include <asm/hyperv-tlfs.h>
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#include <asm/mshyperv.h>
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#include <linux/version.h>
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#include <linux/vmalloc.h>
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#include <linux/mm.h>
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#include <linux/hyperv.h>
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#include <linux/slab.h>
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#include <linux/cpuhotplug.h>
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#include <linux/syscore_ops.h>
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#include <clocksource/hyperv_timer.h>
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void *hv_hypercall_pg;
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EXPORT_SYMBOL_GPL(hv_hypercall_pg);
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/* Storage to save the hypercall page temporarily for hibernation */
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static void *hv_hypercall_pg_saved;
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u32 *hv_vp_index;
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EXPORT_SYMBOL_GPL(hv_vp_index);
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struct hv_vp_assist_page **hv_vp_assist_page;
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EXPORT_SYMBOL_GPL(hv_vp_assist_page);
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void __percpu **hyperv_pcpu_input_arg;
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EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
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u32 hv_max_vp_index;
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EXPORT_SYMBOL_GPL(hv_max_vp_index);
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void *hv_alloc_hyperv_page(void)
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{
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BUILD_BUG_ON(PAGE_SIZE != HV_HYP_PAGE_SIZE);
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return (void *)__get_free_page(GFP_KERNEL);
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}
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EXPORT_SYMBOL_GPL(hv_alloc_hyperv_page);
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void *hv_alloc_hyperv_zeroed_page(void)
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{
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BUILD_BUG_ON(PAGE_SIZE != HV_HYP_PAGE_SIZE);
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return (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
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}
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EXPORT_SYMBOL_GPL(hv_alloc_hyperv_zeroed_page);
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void hv_free_hyperv_page(unsigned long addr)
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{
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free_page(addr);
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}
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EXPORT_SYMBOL_GPL(hv_free_hyperv_page);
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static int hv_cpu_init(unsigned int cpu)
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{
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u64 msr_vp_index;
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struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
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void **input_arg;
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struct page *pg;
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input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
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pg = alloc_page(GFP_KERNEL);
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if (unlikely(!pg))
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return -ENOMEM;
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*input_arg = page_address(pg);
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hv_get_vp_index(msr_vp_index);
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hv_vp_index[smp_processor_id()] = msr_vp_index;
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if (msr_vp_index > hv_max_vp_index)
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hv_max_vp_index = msr_vp_index;
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if (!hv_vp_assist_page)
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return 0;
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/*
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* The VP ASSIST PAGE is an "overlay" page (see Hyper-V TLFS's Section
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* 5.2.1 "GPA Overlay Pages"). Here it must be zeroed out to make sure
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* we always write the EOI MSR in hv_apic_eoi_write() *after* the
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* EOI optimization is disabled in hv_cpu_die(), otherwise a CPU may
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* not be stopped in the case of CPU offlining and the VM will hang.
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*/
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if (!*hvp) {
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*hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO,
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PAGE_KERNEL);
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}
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if (*hvp) {
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u64 val;
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val = vmalloc_to_pfn(*hvp);
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val = (val << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT) |
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HV_X64_MSR_VP_ASSIST_PAGE_ENABLE;
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wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, val);
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}
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return 0;
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}
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static void (*hv_reenlightenment_cb)(void);
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static void hv_reenlightenment_notify(struct work_struct *dummy)
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{
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struct hv_tsc_emulation_status emu_status;
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rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
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/* Don't issue the callback if TSC accesses are not emulated */
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if (hv_reenlightenment_cb && emu_status.inprogress)
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hv_reenlightenment_cb();
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}
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static DECLARE_DELAYED_WORK(hv_reenlightenment_work, hv_reenlightenment_notify);
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void hyperv_stop_tsc_emulation(void)
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{
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u64 freq;
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struct hv_tsc_emulation_status emu_status;
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rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
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emu_status.inprogress = 0;
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wrmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
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rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
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tsc_khz = div64_u64(freq, 1000);
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}
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EXPORT_SYMBOL_GPL(hyperv_stop_tsc_emulation);
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static inline bool hv_reenlightenment_available(void)
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{
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/*
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* Check for required features and priviliges to make TSC frequency
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* change notifications work.
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*/
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return ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
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ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE &&
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ms_hyperv.features & HV_X64_ACCESS_REENLIGHTENMENT;
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}
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__visible void __irq_entry hyperv_reenlightenment_intr(struct pt_regs *regs)
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{
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entering_ack_irq();
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inc_irq_stat(irq_hv_reenlightenment_count);
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schedule_delayed_work(&hv_reenlightenment_work, HZ/10);
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exiting_irq();
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}
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void set_hv_tscchange_cb(void (*cb)(void))
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{
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struct hv_reenlightenment_control re_ctrl = {
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.vector = HYPERV_REENLIGHTENMENT_VECTOR,
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.enabled = 1,
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.target_vp = hv_vp_index[smp_processor_id()]
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};
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struct hv_tsc_emulation_control emu_ctrl = {.enabled = 1};
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if (!hv_reenlightenment_available()) {
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pr_warn("Hyper-V: reenlightenment support is unavailable\n");
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return;
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}
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hv_reenlightenment_cb = cb;
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/* Make sure callback is registered before we write to MSRs */
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wmb();
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wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
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wrmsrl(HV_X64_MSR_TSC_EMULATION_CONTROL, *((u64 *)&emu_ctrl));
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}
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EXPORT_SYMBOL_GPL(set_hv_tscchange_cb);
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void clear_hv_tscchange_cb(void)
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{
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struct hv_reenlightenment_control re_ctrl;
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if (!hv_reenlightenment_available())
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return;
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rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
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re_ctrl.enabled = 0;
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wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
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hv_reenlightenment_cb = NULL;
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}
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EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb);
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static int hv_cpu_die(unsigned int cpu)
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{
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struct hv_reenlightenment_control re_ctrl;
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unsigned int new_cpu;
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unsigned long flags;
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void **input_arg;
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void *input_pg = NULL;
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local_irq_save(flags);
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input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
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input_pg = *input_arg;
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*input_arg = NULL;
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local_irq_restore(flags);
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free_page((unsigned long)input_pg);
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if (hv_vp_assist_page && hv_vp_assist_page[cpu])
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wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0);
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if (hv_reenlightenment_cb == NULL)
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return 0;
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rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
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if (re_ctrl.target_vp == hv_vp_index[cpu]) {
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/* Reassign to some other online CPU */
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new_cpu = cpumask_any_but(cpu_online_mask, cpu);
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re_ctrl.target_vp = hv_vp_index[new_cpu];
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wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
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}
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return 0;
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}
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static int __init hv_pci_init(void)
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{
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int gen2vm = efi_enabled(EFI_BOOT);
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/*
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* For Generation-2 VM, we exit from pci_arch_init() by returning 0.
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* The purpose is to suppress the harmless warning:
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* "PCI: Fatal: No config space access function found"
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*/
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if (gen2vm)
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return 0;
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/* For Generation-1 VM, we'll proceed in pci_arch_init(). */
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return 1;
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}
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static int hv_suspend(void)
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{
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union hv_x64_msr_hypercall_contents hypercall_msr;
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/*
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* Reset the hypercall page as it is going to be invalidated
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* accross hibernation. Setting hv_hypercall_pg to NULL ensures
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* that any subsequent hypercall operation fails safely instead of
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* crashing due to an access of an invalid page. The hypercall page
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* pointer is restored on resume.
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*/
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hv_hypercall_pg_saved = hv_hypercall_pg;
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hv_hypercall_pg = NULL;
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/* Disable the hypercall page in the hypervisor */
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rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
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hypercall_msr.enable = 0;
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wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
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return 0;
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}
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static void hv_resume(void)
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{
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union hv_x64_msr_hypercall_contents hypercall_msr;
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/* Re-enable the hypercall page */
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rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
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hypercall_msr.enable = 1;
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hypercall_msr.guest_physical_address =
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vmalloc_to_pfn(hv_hypercall_pg_saved);
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wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
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hv_hypercall_pg = hv_hypercall_pg_saved;
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hv_hypercall_pg_saved = NULL;
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}
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static struct syscore_ops hv_syscore_ops = {
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.suspend = hv_suspend,
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.resume = hv_resume,
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};
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/*
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* This function is to be invoked early in the boot sequence after the
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* hypervisor has been detected.
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*
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* 1. Setup the hypercall page.
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* 2. Register Hyper-V specific clocksource.
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* 3. Setup Hyper-V specific APIC entry points.
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*/
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void __init hyperv_init(void)
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{
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u64 guest_id, required_msrs;
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union hv_x64_msr_hypercall_contents hypercall_msr;
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int cpuhp, i;
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if (x86_hyper_type != X86_HYPER_MS_HYPERV)
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return;
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/* Absolutely required MSRs */
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required_msrs = HV_X64_MSR_HYPERCALL_AVAILABLE |
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HV_X64_MSR_VP_INDEX_AVAILABLE;
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if ((ms_hyperv.features & required_msrs) != required_msrs)
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return;
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/*
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* Allocate the per-CPU state for the hypercall input arg.
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* If this allocation fails, we will not be able to setup
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* (per-CPU) hypercall input page and thus this failure is
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* fatal on Hyper-V.
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*/
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hyperv_pcpu_input_arg = alloc_percpu(void *);
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BUG_ON(hyperv_pcpu_input_arg == NULL);
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/* Allocate percpu VP index */
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hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
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GFP_KERNEL);
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if (!hv_vp_index)
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return;
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for (i = 0; i < num_possible_cpus(); i++)
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hv_vp_index[i] = VP_INVAL;
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hv_vp_assist_page = kcalloc(num_possible_cpus(),
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sizeof(*hv_vp_assist_page), GFP_KERNEL);
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if (!hv_vp_assist_page) {
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ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
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goto free_vp_index;
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}
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cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
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hv_cpu_init, hv_cpu_die);
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if (cpuhp < 0)
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goto free_vp_assist_page;
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/*
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* Setup the hypercall page and enable hypercalls.
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* 1. Register the guest ID
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* 2. Enable the hypercall and register the hypercall page
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*/
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guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
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wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
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hv_hypercall_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
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if (hv_hypercall_pg == NULL) {
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wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
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goto remove_cpuhp_state;
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}
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rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
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hypercall_msr.enable = 1;
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hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
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wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
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/*
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* Ignore any errors in setting up stimer clockevents
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* as we can run with the LAPIC timer as a fallback.
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*/
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(void)hv_stimer_alloc();
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hv_apic_init();
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x86_init.pci.arch_init = hv_pci_init;
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register_syscore_ops(&hv_syscore_ops);
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return;
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remove_cpuhp_state:
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cpuhp_remove_state(cpuhp);
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free_vp_assist_page:
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kfree(hv_vp_assist_page);
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hv_vp_assist_page = NULL;
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free_vp_index:
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kfree(hv_vp_index);
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hv_vp_index = NULL;
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}
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/*
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* This routine is called before kexec/kdump, it does the required cleanup.
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*/
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void hyperv_cleanup(void)
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{
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union hv_x64_msr_hypercall_contents hypercall_msr;
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unregister_syscore_ops(&hv_syscore_ops);
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/* Reset our OS id */
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wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
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/*
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* Reset hypercall page reference before reset the page,
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* let hypercall operations fail safely rather than
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* panic the kernel for using invalid hypercall page
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*/
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hv_hypercall_pg = NULL;
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/* Reset the hypercall page */
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hypercall_msr.as_uint64 = 0;
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wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
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/* Reset the TSC page */
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hypercall_msr.as_uint64 = 0;
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wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
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}
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EXPORT_SYMBOL_GPL(hyperv_cleanup);
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void hyperv_report_panic(struct pt_regs *regs, long err)
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{
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static bool panic_reported;
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u64 guest_id;
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/*
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* We prefer to report panic on 'die' chain as we have proper
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* registers to report, but if we miss it (e.g. on BUG()) we need
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* to report it on 'panic'.
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*/
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if (panic_reported)
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return;
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panic_reported = true;
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rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
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wrmsrl(HV_X64_MSR_CRASH_P0, err);
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wrmsrl(HV_X64_MSR_CRASH_P1, guest_id);
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wrmsrl(HV_X64_MSR_CRASH_P2, regs->ip);
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wrmsrl(HV_X64_MSR_CRASH_P3, regs->ax);
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wrmsrl(HV_X64_MSR_CRASH_P4, regs->sp);
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/*
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* Let Hyper-V know there is crash data available
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*/
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wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
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}
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EXPORT_SYMBOL_GPL(hyperv_report_panic);
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/**
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* hyperv_report_panic_msg - report panic message to Hyper-V
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* @pa: physical address of the panic page containing the message
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* @size: size of the message in the page
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*/
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void hyperv_report_panic_msg(phys_addr_t pa, size_t size)
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{
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/*
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* P3 to contain the physical address of the panic page & P4 to
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* contain the size of the panic data in that page. Rest of the
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* registers are no-op when the NOTIFY_MSG flag is set.
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*/
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wrmsrl(HV_X64_MSR_CRASH_P0, 0);
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wrmsrl(HV_X64_MSR_CRASH_P1, 0);
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wrmsrl(HV_X64_MSR_CRASH_P2, 0);
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wrmsrl(HV_X64_MSR_CRASH_P3, pa);
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wrmsrl(HV_X64_MSR_CRASH_P4, size);
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/*
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* 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);
|
|
|
|
bool hv_is_hibernation_supported(void)
|
|
{
|
|
return acpi_sleep_state_supported(ACPI_STATE_S4);
|
|
}
|
|
EXPORT_SYMBOL_GPL(hv_is_hibernation_supported);
|