LXR linux/arch/x86/kernel/cpu/acrn.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * ACRN detection support
   4 *
   5 * Copyright (C) 2019 Intel Corporation. All rights reserved.
   6 *
   7 * Jason Chen CJ <jason.cj.chen@intel.com>
   8 * Zhao Yakui <yakui.zhao@intel.com>
   9 *
  10 */
  11
  12#include <linux/interrupt.h>
  13#include <asm/apic.h>
  14#include <asm/cpufeatures.h>
  15#include <asm/desc.h>
  16#include <asm/hypervisor.h>
  17#include <asm/idtentry.h>
  18#include <asm/irq_regs.h>
  19
  20static u32 __init acrn_detect(void)
  21{
  22        return hypervisor_cpuid_base("ACRNACRNACRN", 0);
  23}
  24
  25static void __init acrn_init_platform(void)
  26{
  27        /* Setup the IDT for ACRN hypervisor callback */
  28        alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_acrn_hv_callback);
  29}
  30
  31static bool acrn_x2apic_available(void)
  32{
  33        return boot_cpu_has(X86_FEATURE_X2APIC);
  34}
  35
  36static void (*acrn_intr_handler)(void);
  37
  38DEFINE_IDTENTRY_SYSVEC(sysvec_acrn_hv_callback)
  39{
  40        struct pt_regs *old_regs = set_irq_regs(regs);
  41
  42        /*
  43         * The hypervisor requires that the APIC EOI should be acked.
  44         * If the APIC EOI is not acked, the APIC ISR bit for the
  45         * HYPERVISOR_CALLBACK_VECTOR will not be cleared and then it
  46         * will block the interrupt whose vector is lower than
  47         * HYPERVISOR_CALLBACK_VECTOR.
  48         */
  49        ack_APIC_irq();
  50        inc_irq_stat(irq_hv_callback_count);
  51
  52        if (acrn_intr_handler)
  53                acrn_intr_handler();
  54
  55        set_irq_regs(old_regs);
  56}
  57
  58const __initconst struct hypervisor_x86 x86_hyper_acrn = {
  59        .name                   = "ACRN",
  60        .detect                 = acrn_detect,
  61        .type                   = X86_HYPER_ACRN,
  62        .init.init_platform     = acrn_init_platform,
  63        .init.x2apic_available  = acrn_x2apic_available,
  64};
  65