// SPDX-License-Identifier: GPL-2.0
/*
 * ACRN detection support
 *
 * Copyright (C) 2019 Intel Corporation. All rights reserved.
 *
 * Jason Chen CJ <jason.cj.chen@intel.com>
 * Zhao Yakui <yakui.zhao@intel.com>
 *
 */

#include <linux/interrupt.h>

#include <asm/acrn.h>
#include <asm/apic.h>
#include <asm/cpufeatures.h>
#include <asm/desc.h>
#include <asm/hypervisor.h>
#include <asm/idtentry.h>
#include <asm/irq_regs.h>

static u32 __init acrn_detect(void)
{
        return acrn_cpuid_base();
}

static void __init acrn_init_platform(void)
{
        /* Install system interrupt handler for ACRN hypervisor callback */
        sysvec_install(HYPERVISOR_CALLBACK_VECTOR, sysvec_acrn_hv_callback);

        x86_platform.calibrate_tsc = acrn_get_tsc_khz;
        x86_platform.calibrate_cpu = acrn_get_tsc_khz;
}

static bool acrn_x2apic_available(void)
{
        return boot_cpu_has(X86_FEATURE_X2APIC);
}

static void (*acrn_intr_handler)(void);

DEFINE_IDTENTRY_SYSVEC(sysvec_acrn_hv_callback)
{
        struct pt_regs *old_regs = set_irq_regs(regs);

        /*
         * The hypervisor requires that the APIC EOI should be acked.
         * If the APIC EOI is not acked, the APIC ISR bit for the
         * HYPERVISOR_CALLBACK_VECTOR will not be cleared and then it
         * will block the interrupt whose vector is lower than
         * HYPERVISOR_CALLBACK_VECTOR.
         */
        apic_eoi();
        inc_irq_stat(irq_hv_callback_count);

        if (acrn_intr_handler)
                acrn_intr_handler();

        set_irq_regs(old_regs);
}

void acrn_setup_intr_handler(void (*handler)(void))
{
        acrn_intr_handler = handler;
}
EXPORT_SYMBOL_GPL(acrn_setup_intr_handler);

void acrn_remove_intr_handler(void)
{
        acrn_intr_handler = NULL;
}
EXPORT_SYMBOL_GPL(acrn_remove_intr_handler);

const __initconst struct hypervisor_x86 x86_hyper_acrn = {
        .name                   = "ACRN",
        .detect                 = acrn_detect,
        .type                   = X86_HYPER_ACRN,
        .init.init_platform     = acrn_init_platform,
        .init.x2apic_available  = acrn_x2apic_available,
};