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};