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/acrn.h>
  14 #include <asm/apic.h>
  15 #include <asm/desc.h>
  16 #include <asm/hypervisor.h>
  17 #include <asm/irq_regs.h>
  18
  19 static uint32_t __init acrn_detect(void)
  20 {
  21         return hypervisor_cpuid_base("ACRNACRNACRN\0\0", 0);
  22 }
  23
  24 static void __init acrn_init_platform(void)
  25 {
  26         /* Setup the IDT for ACRN hypervisor callback */
  27         alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, acrn_hv_callback_vector);
  28 }
  29
  30 static bool acrn_x2apic_available(void)
  31 {
  32         /*
  33          * x2apic is not supported for now. Future enablement will have to check
  34          * X86_FEATURE_X2APIC to determine whether x2apic is supported in the
  35          * guest.
  36          */
  37         return false;
  38 }
  39
  40 static void (*acrn_intr_handler)(void);
  41
  42 __visible void __irq_entry acrn_hv_vector_handler(struct pt_regs *regs)
  43 {
  44         struct pt_regs *old_regs = set_irq_regs(regs);
  45
  46         /*
  47          * The hypervisor requires that the APIC EOI should be acked.
  48          * If the APIC EOI is not acked, the APIC ISR bit for the
  49          * HYPERVISOR_CALLBACK_VECTOR will not be cleared and then it
  50          * will block the interrupt whose vector is lower than
  51          * HYPERVISOR_CALLBACK_VECTOR.
  52          */
  53         entering_ack_irq();
  54         inc_irq_stat(irq_hv_callback_count);
  55
  56         if (acrn_intr_handler)
  57                 acrn_intr_handler();
  58
  59         exiting_irq();
  60         set_irq_regs(old_regs);
  61 }
  62
  63 const __initconst struct hypervisor_x86 x86_hyper_acrn = {
  64         .name                   = "ACRN",
  65         .detect                 = acrn_detect,
  66         .type                   = X86_HYPER_ACRN,
  67         .init.init_platform     = acrn_init_platform,
  68         .init.x2apic_available  = acrn_x2apic_available,
  69 };